JP2019049483A - Method for measuring thickness of water repellent layer - Google Patents

Abstract

To enable the measurement of the thickness of a water repellent layer without being affected by change, if any, in resistance value and dielectric constant in relation to water content.SOLUTION: A high frequency output is applied to an equal ratio coplanar electrode in which an equal ratio coplanar electrode constant S/t of a ratio of a horizontal surface distance t to a center position of mutual electrode plates is constant, with two electrode plate of an area S forming a pair. Characteristics of a linear function are acquired between the horizontal surface distance t to the center position of the mutual electrode plates and an indicated value Cd dependent on electrostatic capacitance C, and an output is acquired with (an inverse number 1/a) of the inclination of the characteristics of the linear function as inclination information related to water repellent layer thickness, and also with an intercept b of the indicated value Cd dependent on the electrostatic capacitance C as initial information related to a water content near a surface layer. Thus, the penetration depth or the like of an applied silane-based surface impregnation material is measured, and the water repellent layer thickness of the silane-based surface impregnation material is measured.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a measurement electrode for measuring the difference in moisture content between the inside of a sample and the surface layer portion of a thickness of a water repellent layer coated on a concrete surface, and a method for measuring the same. Belongs to a measurement electrode for measuring the difference in water content between the inside of the sample and the surface layer and the measurement method using the measurement electrode. It is a thing.

For example, in the case of blending concrete aggregate, it is assumed that the surface is in a “surface dry state (surface dry saturated state)”, the density of the aggregate is determined, and blending is performed according to various blending designs. Here, the "surface dry state" is based on the premise that the internal space of the compacted aggregate is filled with moisture, and the surface of the aggregate is free of moisture. .
Generally, the flow cone method standardized in JIS A1109 is employed to determine the surface dry state of aggregate. According to this, the aggregate is filled into a frustoconical flow cone, and the end is pressed to a predetermined hardness by pushing with a push rod, and then the flow cone is gradually pulled upward and the pressed bone is compacted. The condition near the boundary whether the material collapses or does not collapse is judged as the surface dry condition.

However, these determinations of surface dryness require accurate data in which the aggregate is broken. In particular, heuristics are needed to make accurate decisions. Therefore, an unaccustomed measurer may not be able to make an accurate judgment.
In particular, the flow cone method described above is mainly applied to sand, gravel, etc. called “natural aggregate”, but in recent years, the supply amount of this “natural aggregate” has decreased, and Alternatives are used as aggregate. For example, so-called "low grade" aggregates such as crushed sand, blast furnace slag, refuse melting slag, recycled aggregate and the like are widely used. These low-grade aggregates may exhibit vitreous or porous properties on their surfaces, and may have surface-drying characteristics which are clearly different from those of natural aggregates. Therefore, in the flow cone method, it is particularly difficult to determine an accurate surface dry state for aggregates such as crushed sand.
For example, a method of using a new standard surface dry judgment cone formed by a size such as a self-supporting angle or a wide diameter different from the shape of a flow cone standardized by JIS, the moisture content is measured using infrared reflectance The thing (refer nonpatent literature 1), the thing using change of electric resistance in a wet and dry state (refer nonpatent literature 2), the thing using centrifugal dehydration method (refer nonpatent literature 3), etc. are known.

Takeuchi, Kazuma, 3 others "Basic research on surface dry judgment test method of fine aggregate", Annual Proceedings of Concrete Engineering, Vol. 25, No. 1, 2003, p77-p82 Daisuke Yamamoto, 4 others "Consideration on the method for determining the surface dryness of crushed sand as sand and sand substitute aggregate", 59th Annual Conference of the Japan Society of Civil Engineers, September 2004, p 491- 492 Kazuo Suzuki, 1 other person “A study on simple method for determination of fine aggregate by surface dry”, Proceedings of the 48th Cement Technology Conference, 1994, p156-p159 JP, 2006-329801, A

Non-Patent Document 1 uses flow cones formed by different self-supporting angles and sizes, and a certain degree of empirical rule is required for the determination of the surface dry state as in the prior art, and accurate repeatability is sought. It was difficult. Moreover, it was necessary to select the optimal flow cone suitably according to the kind and property of aggregate, and it was necessary to prepare multiple types of flow cone in advance.
In particular, those utilizing the infrared reflectance of Non-Patent Document 1 generally use two types of wavelengths: an infrared wavelength (1.46 μm) that is easily absorbed by water and an infrared wavelength (1.6 μm) that is not easily absorbed by water. And since it was calculated by the data which measured "Shirasu" as an aggregate mainly, it was not disclosed about the action to other low grade aggregate.
In Non-Patent Document 2, various measurements are carried out using crushed sand as a sample to be measured, and by combining various results, the result that the flow cone method has the most appropriate result can be obtained, and the other methods are not. The measurement results of Patent Document 2 did not show particularly excellent characteristics.
And in Non-Patent Document 3, although it becomes possible to judge the surface dry state with high accuracy, the target aggregate is set in the centrifugal separator, and the centrifugal force of several G to several G according to the sample In some cases, the apparatus for determining the surface dry state is bulky and is not suitable for simple determination of the surface dry state.

On the other hand, for the improvement of the durability of the present concrete structure, a method of applying a silane-based surface impregnating material to the surface and permeating the surface, and forming a water repellent layer inside the concrete has attracted attention.
By applying the water repellent layer, the penetration of water can be suppressed, and the penetration of deterioration factors of the concrete such as salt and water can be suppressed, whereby the durability of the concrete can be enhanced. For example, “Hokkaido Development Bureau Road Design Guidelines” stipulates that the penetration depth is 6 mm or more in the measures against frost damage as a standard of product selection of silane-based surface impregnation material.
However, in order to confirm the thickness of the applied water repellent layer, there is a method of drilling in concrete and observing. This method of drilling in concrete would damage the construction product and was not necessarily the preferred method. Then, although it is managed by application amount from the relationship between the application amount to the test object produced beforehand, and the water-repellent layer thickness, the construction actual condition is unknown.
The water repellent layer thickness formed by the surface impregnating material is reported to be affected by the moisture content of concrete. The higher the moisture content, the smaller the penetration depth. At the construction site, the moisture content may be different depending on the location due to the influence of rainfall or solar radiation. For this reason, it is also conceivable that the water repellent layer thickness at the site may cause an error from the estimated value by the amount applied to the sample. Moreover, when apply | coating to the existing concrete structure, the test body produced separately does not remain in many cases, and it can not obtain | require the relationship between the application quantity to a test object, and the water-repellent layer thickness.
From such a thing, when applying a surface impregnation method, the quality of construction can be enhanced by managing with the formed water repellent layer. Therefore, the present inventors have investigated a method of estimating the water repellent layer thickness of concrete using electrical changes due to the water content ratio.

  Therefore, the present inventors have provided a method of determining the surface dry state of aggregate with a relatively simple configuration in Patent Document 1 That is, this is mixing and stirring water in the aggregate in the bone-drying state, and mixing and stirring the water in the aggregate in the bone-drying state and the reference sample preparation step of preparing each to a predetermined moisture content respectively The ionized sample preparation step of preparing an ionized substance having conductivity and adding the ionized material having conductivity and stirring the mixture, and a plurality of reference samples having different water contents prepared by the reference sample preparation step and the ionized sample preparation step And filling the plurality of ionized samples having different moisture contents prepared in the above into the measurement container having a predetermined shape and smoothing the sample surface, and the reference sample filled in the measurement container. And a measurement step of measuring a high frequency capacity by bringing a measurement portion of the high frequency capacity moisture meter into contact with the surface of the sample of the ionized sample, and the high frequency capacity moisture meter A reference sample indicating the relationship between the indicated value and the moisture content of the reference sample or the ionized sample, and the addition sample are prepared, and a surface dry point at which the inclination of the addition sample changes with respect to the reference sample It comprises the table dry judging process which specifies and judges the surface dry state.

Thereby, the moisture meter which measures the moisture content of concrete is improved, and the electric field generated from the electrode plate reaches the concrete by changing the distance between the pair of electrode plates by measuring the capacitance. When the electric field is in the water repellent layer, the capacitance decreases at a constant rate, and when the electric field reaches the high water content simulated non-water repellent layer, the rate of decrease in capacitance changes. The inflection point is defined as the boundary between the water repellent layer and the ordinary layer, and a value relatively close to the measured value is obtained.
However, in the water containing concrete of Patent Document 1, pure H ₂ O is a good insulator, and when the pure H ₂ O is measured, the resistance decreases during the measurement. Also, along with that, the dielectric constant also changes depending on the metal ion, and changes as the frequency characteristic of conductivity and dielectric constant depending on the water content. Also, if the measurement target is a large volume, the electric field spreads and the electric field density changes depending on the position of the electrode plate, the area of the electrode plate, and the height of the applied voltage that determines the electric field. Calculation will be needed.

  Therefore, according to the present invention, even if the resistance value and the dielectric constant change depending on the water content, the effect is unlikely to appear even if the result does not change depending on the water content, and the inside and surface layer of the specimen from which the thickness of the water repellent layer can be measured An object of the present invention is to provide a measurement electrode for measuring a difference in moisture content with a part and a measurement method using the measurement electrode.

  The measurement electrode for measuring the difference in the moisture content between the inside of the sample of the invention of the present invention and the surface layer portion is a pair of electrode plates having the same area of the electrode plate area S, and the electrode plate area S and the electrode The equal ratio coplanar electrode constant S / t, which is the ratio of the horizontal distance t to the center position between the plates, is constant, and except for the different areas of the pair of equal ratio coplanar electrodes An output is applied, and a characteristic of a specific linear function is obtained between a horizontal distance t to the center position of the electrode plates and a display value Cd depending on the capacitance C, and a slope a of the characteristic of the linear function Is the inclination information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is output as initial information related to the moisture content near the surface layer.

Here, the ratio of the horizontal surface distance t of each of the test pieces to the central position between the electrode plates and the area S of each electrode plate may be constant. In particular, it is the isometric coplanar electrode constant S / t that satisfies it. However, even if the geometrical ratio coplanar electrode constant S / t is the same, those having a different pair of electrode plate areas are excluded.
Further, the horizontal distance t of the above-mentioned equal ratio coplanar electrode constant S / t can be made equal to the facing average distance d between the facing electrode plates on the linear distance. However, since the form of the electric field is determined for the horizontal distance t and the facing average distance d, it is desirable that the both be the same and be offset by the calculation formula.
The slope of the characteristic of the linear function can be the slope of the characteristic or the reciprocal 1 / a of the inclination of the characteristic. In any case, a high frequency output is applied to the equal ratio coplanar electrodes on both sides of a fixed equal ratio coplanar electrode, and the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C The characteristics of the linear function may be drawn between the two.

The horizontal distance t of the equal ratio coplanar electrode constant S / t of the measurement electrode for measuring the difference in the moisture content between the inside of the specimen of the invention of the present invention and the surface layer portion is the facing average distance between the opposing electrode plates It is identical to d.
Here, if the horizontal distance t of the uniform coplanar electrode constant S / t and the value obtained by multiplying the horizontal distance t by the circular ratio π is equal to the inter-plate distance d, the electric field draws an arc, and It can be assumed that there is a distance d between the electrode plates at the center position.

The slope of the characteristic of the linear function of the measurement electrode for measuring the difference in the moisture content between the inside of the specimen of the invention according to the third aspect of the present invention and the surface portion is the reciprocal 1 / a of the inclination of the characteristic.
Here, the slope a of the characteristic may be used as its reciprocal 1 / a.

  The measurement method using a measurement electrode for measuring the difference in moisture content between the inside of the specimen of the invention according to the invention and the surface layer portion uses two electrode plates having an electrode plate area S as a pair. The ratio of the ratio of the horizontal plane distance t to the center position of the electrode plates to the area of each electrode plate S is constant, and the area of the pair of equal ratio coplanar electrodes is different. The high-frequency output is applied to the uniform ratio coplanar electrodes except for the above, and the characteristic of the linear function is obtained between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the electrostatic capacitance C. (Reciprocal number 1 / a) of the slope of the characteristic of the property is the slope a information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is an initial stage related to the moisture content near the surface layer An output is obtained as information.

Here, except that the electrode plate areas of the pair of equal ratio coplanar electrodes are different from each other, the high ratio is applied to both sides of the equal ratio coplanar electrodes to reach the center positions of the electrode plates. The ratio of the horizontal distance t of the specimen to the electrode plate area S may be constant. In particular, it is the isometric coplanar electrode constant S / t that satisfies it.
Further, the horizontal distance t of the above-mentioned equal ratio coplanar electrode constant S / t can be made equal to the facing average distance d between the facing electrode plates on the linear distance. However, it is preferable that the horizontal distance t and the facing average distance d be the same because they are determined by the electrostatic field and the electric field, and they should be offset by a calculation formula.
The slope of the characteristic of the linear function can be the slope of the characteristic or the reciprocal 1 / a of the inclination of the characteristic. In any case, a high frequency output is applied to the equal ratio coplanar electrodes on both sides of a fixed equal ratio coplanar electrode, and the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C The characteristics of the linear function may be drawn between the two.

  The invention of the measurement electrode for measuring the difference in the moisture content between the inside of the test piece and the surface layer portion according to claim 1 comprises two electrode plates having an electrode plate area S as a pair, and the electrode plate area S and the electrode plate mutually The high ratio output is added to the equi-coplanar electrode except for the cases where the ratio of the ratio to the horizontal distance t to the center position of the is constant S / t is constant and the area of the pair of non-coplanar electrodes is different. The characteristic between the horizontal surface distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C is obtained, and the slope a (reciprocal number 1 / a) of the characteristic of the linear function is a water repellent layer Inclination information related to the thickness is obtained, and the intercept b of the display value Cd dependent on the capacitance C is output as initial information related to the moisture content near the surface layer.

Therefore, when the water repellent layer formed with a small coating amount is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the water repellent layer formed with a small amount of application is thin, the slope a is large, and when it is thick, it decreases. Therefore, the reciprocal 1 / a of the slope of the regression line of each specimen is expressed as the water repellent layer You can also Regarding the relationship between the reciprocal 1 / a of the slope of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.
Therefore, between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, a high frequency output is applied to the equal ratio coplanar electrode of which the equal ratio coplanar electrode constant S / t is constant. The characteristic of the linear function equation is obtained, and (reciprocal number 1 / a) of the inclination of the linear function equation is used as the inclination information related to the water repellent layer thickness, and the display value Cd depending on the capacitance C The segment b obtains an output as initial information related to the moisture content near the surface layer. Thereby, for example, the penetration depth and the like of the silane-based surface impregnated material are measured, and the water-repellent layer thickness of the silane-based surface impregnated material is measured as a regression line.

  The horizontal distance t of the equal ratio coplanar electrode constant S / t of the invention of the measurement electrode for measuring the difference in the moisture content between the inside of the specimen according to claim 2 and the surface layer portion is the facing average between the facing electrode plates In addition to the effects described in claim 1, since the same position as the distance d, the horizontal distance t and the horizontal distance t at which the equal ratio coplanar electrode constant S / t satisfies a constant value Since the value obtained by multiplying is the same as the inter-plate distance d, the electric field draws an arc, and the inter-plate distance d can be calculated as a regression line at the center of the arc.

  The slope of the characteristic of the linear function equation of the invention of the measuring electrode for measuring the difference in the moisture content between the inside of the specimen according to claim 3 and the surface portion is the reciprocal 1 / a of the inclination of the characteristic. From the above, in addition to the effect described in claim 1 or claim 2, the reciprocal 1 / a of the slope of the characteristic of the linear function equation is the slope information related to the water repellent layer thickness, and The intercept b of the dependent display value Cd obtains an output as initial information related to the moisture content near the surface layer.

  The invention of the measurement method using a measurement electrode for measuring the difference in moisture content between the inside of the specimen and the surface layer portion according to claim 4 makes two electrode plates of the electrode plate area S a pair, and the electrode plate area S Isometric ratio coplanar electrode constant S / t of the ratio of the ratio to the horizontal distance t to the center position of the electrode plates and the area of the pair of equal ratio coplanar electrodes is constant. A high frequency output is added to obtain a characteristic between the horizontal distance t to the center position of the electrode plates and a display value Cd depending on the capacitance C, and a slope a (reciprocal 1 / reciprocal of the characteristic of the linear function equation is obtained. Let a) be inclination information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C obtain an output as initial information related to the moisture content near the surface layer.

Therefore, when the water repellent layer formed with a small coating amount is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the water repellent layer formed with a small amount of application is thin, the slope a is large, and when it is thick, it decreases. Therefore, the reciprocal 1 / a of the slope of the regression line of each specimen is expressed as the water repellent layer You can also Regarding the relationship between the reciprocal 1 / a of the slope of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.
Therefore, between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, a high frequency output is applied to the equal ratio coplanar electrode of which the equal ratio coplanar electrode constant S / t is constant. The characteristic of the linear function equation is obtained, and (reciprocal number 1 / a) of the inclination of the characteristic of the linear function equation is the inclination information related to the water repellent layer thickness, and the display value Cd depending on the capacitance C The intercept b of b provides an output as initial information related to the moisture content near the surface layer. Thereby, for example, the penetration depth and the like of the silane-based surface impregnated material are measured, and the water-repellent layer thickness of the silane-based surface impregnated material is measured as a regression line.

FIG. 1 is a basic explanatory view illustrating a measurement electrode for measuring the difference in moisture content between the inside of the test piece and the surface layer according to the embodiment of the present invention and a measurement method using the measurement electrode. FIG. 2 is a basic block diagram of the embodiment of the present invention. FIG. 3 is an explanatory view showing the relationship between the water content used in the embodiment of the present invention and the display value in the case where the simulated non-water repellent layer is constant. FIG. 4 is a characteristic diagram showing the relationship between the horizontal distance and the display value according to the simulated specimen used in the embodiment of the present invention. FIG. 5 is an explanatory view showing the relationship between the slope and the intercept of the regression line used in the embodiment of the present invention. FIG. 6 is a characteristic diagram showing the relationship of the intercept at each moisture content used in the embodiment of the present invention. FIG. 7 is a characteristic diagram showing the relationship of the reciprocal of the slope in each moisture content used in the embodiment of the present invention. FIG. 8 is an explanatory view showing the composition of the concrete sample to be measured in the embodiment of the present invention. FIG. 9 is an explanatory view showing the physical properties of the aggregate of the concrete sample to be measured in the embodiment of the present invention. FIG. 10 is a characteristic diagram showing the change of the capacitance of the concrete sample to be measured in the embodiment of the present invention. FIG. 11 is a characteristic diagram showing the reciprocal of the inclination and the water repellent layer thickness measured in the embodiment of the present invention. FIG. 12 is a characteristic diagram of the display value of the test sample of stationary day 1 having the inclined water content distribution measured in the embodiment of the present invention. FIG. 13 is a characteristic diagram of the display value of the specimen of stationary 7 days having the inclined water content distribution measured in the embodiment of the present invention. FIG. 14 is a measurement result diagram showing measured values and estimated values measured in the embodiment of the present invention.

  Hereinafter, a measurement electrode for measuring the difference in moisture content between the inside of the specimen and the surface layer portion of the embodiment of the present invention and a measurement method using the measurement electrode will be described based on the drawings. Note that, in the embodiment, the same symbols and symbols in the drawings are the same or corresponding functional parts, and therefore the description thereof will not be repeated here.

Embodiment
First, a measurement electrode for measuring the difference in moisture content between the inside of the sample and the surface layer portion and the basic principle of the measurement method using the measurement electrode will be described.
In the present invention, a pair of electrodes is a parallel plate, and the configuration of a capacitor in which a dielectric of dielectric constant ε is sandwiched therebetween is used. The electrode plate area S of the parallel electrode plates is in the state of being disposed apart by the facing average distance d between the electrode plates opposite to each other in parallel. The capacitance C of the electrode plate of the electrode plate area S at this time is proportional to the dielectric constant ε of the dielectric between the electrode plate area S and the electrode plate, and the capacitance C of the electrode plate is S The capacitance C is expressed by the following equation.
C = ε · S / d
Where C (F) capacitance
S (m ² ) Electrode plate area between facing electrode plates
d (m) opposing average distance between opposing electrode plates
ε (F / m) is the dielectric constant of the dielectric between the electrode plates.

As the high frequency source, since the inventors are used to handling, a commercially available high-frequency capacitive moisture meter (HI-520: manufactured by Ketto Scientific Research Institute, Inc., high-frequency capacitive type (20 MHz)) electrodes 17 and 18 The high frequency output from was used.
In the experiments of the inventors, a high-frequency capacitive moisture meter is used instead of the LCR meter, but as a result, the value of the capacitance C is not measured, but the output is relayed. The capacitance C of the test material (aggregate) is not calculated based on the dielectric constant ε at a high frequency (20 MHz).
If a general LCR meter is used, it is necessary to consider the influence of stray capacitances of the electrodes 17, 18, etc. As a result, it is considered that a commercially available high frequency capacitive moisture meter is more useful.

First, when water is included in the aggregate of the test material, a phenomenon occurs in which the capacitance C increases with the increase of water. Usually, when the capacitance C is calculated from the dielectric loss tangent tan δ,
It is expressed by the current Ir of the resistance component / the current Ic of the capacitor capacitance component, and the equation is
tan δ = Ir / Ic
It becomes.
However, the dielectric constant of about 80 of water changes with the change of temperature and also changes with the frequency applied, and a chemical reaction occurs and also changes with the application time and the like. This is largely due to the action of melting by ions and the like.
Moreover, although the electrostatic capacitance C is calculated as C = (epsilon) * S / d, the area | region pinched | interposed between electrodes can also be caught as a resistor.
Therefore, as the phenomenon, when the aggregate of the test material is made to contain water, the capacitance C increases with the increase of water, so it was decided to capture only that event.
The amount of increase in capacitance C as the water content increases is converted in accordance with a conversion formula previously obtained using mortar, concrete, and various other test materials, and is displayed as the water content. Here, in the test material having no conversion formula, the mode is switched to the direct mode (D mode) of a commercially available high-frequency capacitive moisture meter, and a numerical value correlated with the capacitance C is displayed as a display value Cd. As a precaution, the display value of the direct mode used by the inventors is displayed between "0 and 2999".

  A high frequency output (AC voltage) was applied to both electrode plates, and a band-like electric field was generated therebetween, and the capacitance C of the test material on this electric field was measured. The shape of the electric field is considered to be arc-like or elliptical depending on the boundary conditions etc. However, "It is possible to evaluate the amount of dielectric physical properties to a depth proportional to the electrode spacing (S. Tetsuro:" by dielectric measurement with surface depth resolution Since it is said that “Development diagnosis technology for polymer electrical insulation materials” (FY 2004-2006 Grant-in-Aid for Scientific Research Grants), the opposing distance d between the electrode plates and the depth of the electric field It was assumed that it was a circular arc shape that was simply proportional. The electrode plates were arranged in parallel, and the electric field was transmitted through the test material, and it was assumed that the depth to which the electric field reached changes by changing the center distance d of the electrode plates.

Further, the dielectric constant ε of the dielectric changes in accordance with the water content. Further, the distance d between the electrode plate centers is the facing average distance of the arc-like electric field. When the facing average distance d between the electrode plates is small, the electric field exists only in the simulated water repellent layer 41, and the capacitance C decreases with the increase in the facing average distance d between the electrode plates. When the electric field reaches the simulated non-water repellent layer 42 having a high water content, the dielectric constant ε also changes, and the reduction rate of the display value Cd changes.
Therefore, logically, this inflection point is the boundary between the simulated water repellent layer 41 and the simulated non-water repellent layer 42. The estimated value of the water repellent layer thickness at this time was close to the confirmed value confirmed by the measurement. However, if the simulated water repellent layer 41 is thin, an inflection point appears immediately, which makes it difficult to determine the inflection point. In addition, when the width of the electrode plate is narrowed for thin water-repellent layer thickness measurement, there is a disadvantage that the accuracy is lowered. That is, it is estimated that the electric field affects the side of the non-water repellent layer 42 from the beginning.

Next, the electrode plates 21, 22, 21A, 22A shown in FIG. 1 used in the embodiment of the present invention will be examined.
An electrode was manufactured such that the ratio S / t of the horizontal plate distance t from the center position of one electrode plate to the center position of the other electrode plate and the electrode plate area S was constant. An electrode in which the ratio S / t of the horizontal plane distance t to the electrode plate area S is constant is referred to as a "equal ratio coplanar electrode". Further, although the horizontal distance t is defined for the electrode plates 21, 22, 21A, 22A, it may be a vertical surface or may have a predetermined inclination. Here, in order to clarify the difference with the facing average distance d between electrode plates, it is called horizontal surface distance t. Here, S / t = const is referred to as "equal ratio coplanar electrode constant".

Here, a value obtained by multiplying the horizontal distance t by the circle ratio π is set as the inter-plate distance d.
π · t = d
t = d / π
It becomes.
Therefore,
S / t = S · π / d
It becomes. The circle ratio π is constant, and the uniform coplanar electrode constant S / d is always constant.
In addition, the capacitance C is constant, if the dielectric constant ε, that is, the water content does not change in the depth direction, according to C = ε · S / d.
Then, when the horizontal distance t is sequentially increased, when the electric field reaches a portion with high water content, the capacitance C changes for the first time, and the value of the changed position becomes the depth of the simulated water repellent layer 41 .

The inventors further investigate iso-coplanar electrodes 21, 22, 21A and 22A (hereinafter, these will be collectively referred to as “e-coplanar electrode 20”).
Five types of equal ratio coplanar electrodes 20 having horizontal surface distances t of 4, 8, 12, 16, and 20 mm were produced. The electrode plate length of the equal ratio coplanar electrode 20 was constant at 100 mm, and the electrode plate width was changed to set the equal ratio coplanar electrode constant S / t = 100. In this case, since the width of the electrode plate offsets the horizontal distance t, the facing average distance d between the electrode plates and the horizontal distance t of the equal ratio coplanar electrode 20 are the same (the facing average distance d between the electrode plates d = horizontal distance t) And Here, electrode plates having different areas of the pair of equal ratio coplanar electrodes 20 were excluded.

As a material of an electrode plate, as shown in FIG. 2, the copper foil tape 10 was stuck on the plastic film 11, and also the plastic film 11 was stuck on the polystyrene foam 12 of 25 mm. Vinyl coated copper wires 15 and 16 were attached to the copper foil tape 10 as an electrode plate and extended, and brought into contact with the electrodes 17 and 18 of a commercially available high-frequency capacitive moisture meter. Although the lengths of the vinyl-coated copper wires 15 and 16 as lead wires are different in FIG. 2, they are uniform in length in the test circuit. The circuit has symmetry and is drawn out on the opposite side.
In particular, when both vinyl coated copper wires 15 and 16 are brought close to each other, they are influenced by the electrostatic stray capacitance and affect the displayed value Cd of the output, so they are separated from each other so that the influence becomes the minimum value. In order to electrically connect only the upper surface of the electrode 21A (21) and the electrode 22A (22) to the upper surface of the simulated sample, a wrap film 14 is applied to electrically insulate the other upper surface of the simulated sample.
Also, a 2 kg weight 13 was placed on the polystyrene foam 12 in order to bring the copper foil tape 10 into close contact with the test piece.

Using the equal ratio coplanar electrode 20 manufactured in this manner, a simulated specimen with a constant water content was manufactured, and the characteristics of the display value Cd of the carbon plate and the concrete were measured. A caikale plate is easily processed at a thickness of 5 mm, has a high water absorption rate, and has a high water absorption rate, and was adopted as a simulated specimen.
A sample of 5 mm in thickness x 100 mm in length x 100 mm in width is subjected to oven drying at 105 ° C. for 24 hours to obtain a water content of 0%. The sample was placed in a plastic bag with water of such a mass as to cause water absorption, and was then absorbed to make a sealed test sample. Then, as shown in FIG. 3, a caical plate having a moisture content of 0, 6, 12% when the whole of the simulated specimen was 100% was manufactured. In addition, concrete manufactured cubes with a moisture content of 0, 4 and 6.4%.

Here, since the bone dry plate has an absolute dry density of about 0.7 g / cm ³ , which is about 1/3 of that of concrete, the amount of water containing water is about 1⁄3 of that of concrete with the same water content. Eight equal carbon content plates having the same water content were stacked to prepare an equal ratio coplanar electrode 20, and the value of the display value Cd was measured.
The concrete was prepared by cutting a 100 × 100 × 400 mm concrete simulation specimen prepared with a 55% water / cement ratio into cubes of 100 mm square and saturated with water to obtain a surface dry state (water content: 6.4%) What was adjusted so that the moisture content and the moisture content of the same dimensions as that of the one were adjusted to 4.0% and 0% was put in a plastic bag and sealed, and water was uniformly adsorbed to obtain a simulated specimen of a predetermined moisture content.
Here, the relationship between the horizontal distance t of the simulated specimen and the display value Cd is shown in FIG.

As shown in FIG. 3, it can be seen that the display value Cd is substantially constant even if the horizontal surface distance t is changed, if the water content of the concrete and the carbon plate is constant. Once the indicated value Cd and the specimen such as concrete or caulcal plate are known, the moisture content of the specimen is specified. Here, it is presumed that the error of the indicated value Cd is due to the difference in the characteristic of the moisture content distribution to the caulcal board and the general relation of the concrete, and the difference in the moisture content depending on the individual.
In addition, even if the horizontal distance t to the electrode plate center position at each moisture content increases, it is confirmed that the value of the display value Cd does not change and becomes substantially constant even if the horizontal distance t decreases.
Then, if the equi-coplanar electrode constant S / t is constant, the dielectric constant ε (water content) changes even if the horizontal distance t to the electrode center position is increased and the position where the electric field reaches is deepened. If not, the display value Cd is the same value. Then, the result was obtained that the value of the display value Cd becomes larger as the moisture content becomes higher. From this, it can be seen that the indicated value Cd depends on the water content.

Next, measurement of the simulated specimen of the simulated water repellent layer 41 is performed using this equal ratio coplanar electrode 20.
1 or 2 or 3 sheets of 0, 6 and 12% silicon plates are placed on the concrete cubes with water content of 6.4% and 4.0% shown in FIG. 2 and FIG. 3, and lamination of each electrode plate The display value Cd was measured in the state. The carbon plate is a two-layer simulated specimen model in which the simulated water repellent layer 41 having a low water content is simulated, and the concrete non-water repellent layer 42 having a high water content is simulated.

As shown in FIG. 4, one, two, three, or four pieces of silicon boards with a moisture content of 0% are stacked on concrete having a dielectric constant ε and a moisture content of 6.4%, and the horizontal distance t to the electrode plate center position and each display The relationship of the value Cd is illustrated.
As shown in FIG. 4, the inclination of the straight line is large when the thickness of 5 mm of the silicon plate is as thin as one, and the inclination is small when the thickness of three laminated sheets is 15 mm.
Further, the intersection point of the y-axis intersecting the y-axis at x = 0 which does not depend on the thickness of the caiscal plate, that is, the intercept b of the display value Cd is substantially the same value. The value showed a value close to the indicated value Cd = 1270 in the case of overlapping the silica plates having a water content of 0% shown in FIG. A linear relationship, ie, a linear function equation of the display value Cd, is also used in the case of using a calcium carbonate of other moisture content
Display value Cd = ax + b = ax + 1270
The display value Cd is the vertical axis (y), and x is the horizontal axis.
was gotten. The intercept b of the indicated value Cd is shown in FIG.
The slope of each straight line obtained by linear regression of the relationship between the display value Cd and the horizontal distance t obtained by changing the moisture content of concrete and caycal board and the number of stacked caical boards and changing it. An intersection point of a and x = 0 y axis (display value Cd) is a display value Cd.

The larger the difference between the moisture content of the cical plate regarded as the simulated water repellent layer 41 and the moisture content of concrete regarded as the simulated non-water repellent layer 42, the larger the inclination of the regression line. It is considered that if the impedance of the capacitance Ca of the caical plate and the impedance of the capacitance Cb of concrete are considered to be connected in series, when Ca 接 続 Cb by the comparison of impedances, the capacitors are connected in series The amount of work is dependent on Ca, which has a large capacitance impedance.
In particular, when the moisture content of concrete is 4% and the moisture content of the cical plate placed above is 12%, the difference between the moisture content of the two is not so large, the inclination becomes negative when the number of cical plates is increased. , The correlation coefficient of the regression line also decreases.
In addition, when the thickness of the simulated water repellent layer 41 was large, that is, as the number of the silica plates was increased, the inclination was reduced. In the case where the moisture content of the caycal plate is the same, as shown by the relationship between the moisture content and the segment shown in FIG. 6, the values of the segment b become substantially the same even if the number of overlapping sheets is changed. In particular, since the water content is constant and there is no change in the water content, it is estimated that the same can be obtained regardless of how many sheets are used.
Also, it is considered that the simulated water repellent layer 41 is a desirable measurement method because the moisture content is very small.

In addition, in the case of three caical plates (15 mm thick), the display value Cd does not change with electrodes having a horizontal distance t of 4 mm and 8 mm, so the electric field has a large effect on the simulated non-water repellent layer 42 with high moisture content It is presumed that there is no
Although it was estimated that the display value Cd would increase rapidly at 12 mm and 16 mm or more starting to reach the simulated non-water repellent layer 42, the display value Cd would increase continuously and a linear relationship was obtained between the horizontal distance t and the display value Cd. No continuous points occurred. The electric field shape is also presumed to be an arc when the electrode plates face each other in the opposite state, but the electric field in the sample is the same as the sum of the capacitances as impedances connected in series between equal ratio coplanar electrodes 20. Detailed analysis, such as investigation of the influence of the difference in the shape of the water content and the moisture content, will be the subject for future study.

The moisture content of the caking plate piled up at 6% and 4% of the concrete content, the reciprocal of the slope 1 / a of the regression line obtained by changing the thickness of the caking plate with 0% and 12%, respectively The relationship with the thickness of the caycal plate is shown in FIG. The linear relationship which can be shown by a linear function equation was obtained for the reciprocal 1 / a of the slope and the thickness of the caycal plate, respectively.
From this, if the relationship between the reciprocal 1 / a of the slope and the thickness of the water repellent layer is determined in advance for each sample, the regression line of the horizontal distance t and the display value Cd obtained by measuring with the equal ratio coplanar electrode 20 The water repellent layer thickness can be estimated from the slope a or the reciprocal 1 / a of the slope.

Next, it examines using the day of these obtained mock specimens.
First, a concrete simulation sample on which a simulation water repellent layer 41 was formed was measured with a uniform ratio coplanar electrode 20, and the reciprocal 1 / a of the slope of the regression line as obtained for the simulation sample and the water repelling layer thickness Examine the relationship.
The concrete used three types of compounding. The composition of the concrete and the 28-day compressive strength are shown in FIG.
The water to cement ratio (referred to as W / C in FIG. 8) was 40, 55, 70%. Relatively low quality such as ordinary concrete with 55% water / cement ratio and 5% air content, which are used in general structures, and 40% water / cement ratio assuming relatively high strength The amount of air can be reduced without using an AE agent (a type of surfactant, an additive that improves the efficiency of concrete placement and the freeze resistance) at a low water-cement ratio of 70% assuming concrete. It was decided to be. The cement used was early-strength cement.
The physical properties of the used aggregate are shown in FIG. The coarse aggregate used grated stone from Nagara River, and the fine aggregate was a mixture of coarse sand and fine sand from Nagara River at a ratio of 7: 3.
Here, s / a is a fine aggregate rate (the ratio of the volume of the fine aggregate to the volume of the total aggregate), and in this case, s / a = 40%. Moreover, S1 is a coarse thing among fine aggregates, S2 is a fine thing among fine aggregates, G is a coarse aggregate.

As shown in FIG. 8, two types of curing were used: curing in water and curing in air for 28 days after demolding.
A specimen of a square column of 100 mm × 100 mm × 400 mm was prepared, and after curing, it was cut using a concrete cutter to make 50 mm × 100 mm × 130 mm. After making a bank on a 100 mm × 130 mm cut surface so that the surface impregnating material does not drip on the side surface of the sample, it was dried in an oven to be completely dried, and further, the surface impregnating material was applied.
The surface impregnating material is manufactured by TOOKEN CHEMICAL CO., LTD. (Product name S-7; hereinafter simply referred to as "made by T company") and Daido Paint Co., Ltd. (product name aqua seal 1400; hereinafter referred to simply as "made by company D") Was used. The product of company T is liquid, and the product of company D is gel.
Both of the components were silanes, and the standard amount used was 200 g / m ² . The coating amount was set to ^{100g / m 2 ~500g / m 2} , a portion of the specimen number was applied 50 and 800 g / m ^2. The number of specimens was 68 in all.

After leaving for 4 days or more after application so as to form the simulated water repellent layer 41, the sample was placed in a container and immersed in water. The depth of water was set to the height of the specimen, and water was allowed to absorb from the bottom and the side of the specimen for 4 days. The simulated water repellent layer 41 has a very low water absorption rate, and the simulated non-water repellent layer 42 has a high water absorption rate, so the simulated water repellent layer 41 has a small water content like the simulated sample and the simulated non water repellent layer has a high water content. Forty-two two-layer specimen models were constructed.
Fig. 10 shows that 100, 300, 500 g / m ² of surface impregnated material from T Co. is applied to those cured in water at a cement ratio of 55% with water, but the horizontal distance t to the electrode plate center position and the indicated value Cd Show the relationship between It shows that a linear relationship (linear characteristic) can be obtained in the display value Cd depending on the horizontal distance t to the electrode plate center position and the capacitance C as in the case of the simulated specimen.
After the measurement, each sample was split and the actually formed water repellent layer thickness was measured. The measurement averaged the value in the center part and the part of the position of 25 mm on both sides. When the simulated water repellent layer 41 formed with a small coating amount is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b has substantially the same value, and the water content of the water repellent layer portion is considered to be the same.
The coating amount of the surface impregnating material is 100, 300 and 500 g / m ² , but the inclination a is large when the water repellent layer formed with a small coating amount is thin, and is small when it is thick.
In this way, the slope a is obtained as a linear function of the relationship between the display value Cd measured by the electrode shown in FIG. 10 and the distance t to the center of the electrode. As in the case of 4.8 mm, 10.2 mm and 14.0 mm in FIG. 10, the sample is divided to obtain the actual water repellent layer thickness.

Furthermore, FIG. 11 shows the relationship between the reciprocal 1 / a of the slope of the regression line of each simulated specimen and the measured value of the water repellent layer thickness.
The Y axis in Figure 11 uses the water repellent layer thickness actually measured by dividing the sample, and the X axis uses the reciprocal 1 / a of the slope a to obtain a linear function.
As a formula,
The water repellent layer thickness is 164.5 × (1 / a) + 1.302.
If the sample whose water repellent layer is unknown is measured with an electrode and the inclination a is obtained, the water repellent layer can be determined from this equation.
In FIG. 11, the number of test specimens is 68, which is the sum of simulated test specimens coated with T company and D company. The reciprocal 1 / a of the slope is confirmed from the water repellent layer thickness X measured by making the reciprocal 1 / a of the slope of each simulated specimen and the intercept b of the measured value of the water repellent layer common to the indicated value Cd. Be done.
Therefore, the reciprocal 1 / a of the slope is determined from the straight line of the linear function equation expressed by the 68 data, and if the reciprocal 1 / a of the slope is identified, the water repellent layer thickness is identified.
A linear relationship was obtained for the reciprocal of the slope and the water repellent layer thickness as in the case of the simulated specimen. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.

Next, a measurement method using a measurement electrode will be described, in which a test body assuming an actual structure is prepared and a difference in moisture content between the inside of the actual test body and the surface layer portion is measured.
In the sample described above, the simulated water repellent layer 41 has a low moisture content, and the simulated non-water repellent layer 42 has a two-layer sample model with a high moisture content close to the surface dry state.
However, in an actual structure, the water content is not a two-layer sample model, but is estimated to be a slope distribution in which the vicinity of the surface is low and the height gradually increases toward the center. Assuming a slope distribution, the prismatic specimen cured in water at a cement ratio of 55% with water is divided into two equal parts, and those sealed with a rubber-based paint to prevent entry and exit of water except for the cut surface are immersed for 3 days, It stood still in the laboratory for 7 days and 1 day. Two of them were allowed to stand.
The seven-day Gifu Meteorological Observatory records that this test was conducted showed an average temperature of 6.3 ° C and an average humidity of 62%. After standing, 200 g / m ^{2 of a} surface impregnating material manufactured by D was applied to the cut surface. The indicated value Cd was measured with the electrode before application and 4 days after application.
After the measurement, it was split to measure the simulated aqueous layer depth. The relationship between the horizontal distance t to the electrode center before application and after application and the display value Cd is illustrated.

As for what was dried for 1 day, as shown in FIG. 12, the display value Cd before application becomes a value close to the display value Cd = 1900 of the surface dry state (water content 5.2%) even when the horizontal distance t is 4 mm. Most of the water is not evaporated, and it is presumed to be in a saturated state. Although the indicated value Cd decreased even after the application, it was an almost constant value and a clear slope was not obtained, and the water repellent layer thickness could not be estimated.
The estimation of the water repellent layer thickness in a moisture content distribution with a slope assuming an actual structure may have few experimental examples and may need to be corrected in the future. In the future, it is necessary to further study, such as changing the moisture content.

In addition, as shown in FIG. 13, the display value Cd before application is as low as 1900 at a horizontal distance t of 4 mm, the display value Cd is as low as 1900, and is substantially the same for 8 mm or more. It has become. The indicated value Cd at 8 mm or more is a value close to the indicated value of the concrete in the surface dry state (water content: 6.4%) shown in FIG. 3, and it is considered that the inside is saturated.
After application, the display value Cd decreased at 4, 8 and 12 mm, and became a value close to the value before application at 16 mm or more. Linear regression was performed using the value up to 16 mm at which the increase in the display value Cd after application almost disappeared, and the slope a was determined. An estimated value and an actual measurement value obtained by estimating the water repellent layer thickness from the relationship between the inverse 1 / a of the slope and the water repellent layer thickness using the slope a are shown in FIG. The estimated value and the measured value show relatively close values.

The measurement electrodes for measuring the difference in moisture content between the inside of the test piece of the above embodiment and the surface layer portion are a pair of two of the same electrode plate area S, and the horizontal distance t to the center position between the electrode plates Apply high frequency to the equal ratio coplanar electrode 20 and the equal ratio coplanar electrode 20 on both sides except that the ratio equal ratio coplanar electrode constant S / t is constant and the areas of the pair equal ratio coplanar electrodes are different from each other And a linear function equation Y = aX + Cd characteristic is obtained between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C based on the high frequency, and the inclination a of the characteristic of the linear function Or the reciprocal 1 / a is the inclination information related to the water repellent layer thickness, and the intercept b of the display value Cd dependent on the capacitance C is an output that is obtained as initial information related to the moisture content near the surface layer is there.
Here, by measuring gypsum board, concrete, ALA concrete (artificial lightweight aggregate concrete), ALC, mortar, calcium silicate board, D mode, S mode characteristics, as initial information related to the moisture content near the surface layer An intercept b of the display value Cd is calculated.
Further, if the reciprocal 1 / a of the slope in the characteristic of the linear function equation is the inclination information related to the water repellent layer thickness, and if the reciprocal 1 / a of the inclination of the characteristic of the known linear function equation is set as a standard In addition, if the point at which the display value Cd dependent on the capacitance C matches is determined, the water repellent layer thickness can be calculated.

The measurement electrode for measuring the difference in moisture content between the inside of the test piece of the above embodiment and the surface layer portion is a pair of two electrode plate areas S, and the electrode plate area S and the center position between the electrode plates For example, a 20 MHz high frequency output is applied to a constant ratio coplanar electrode having a constant ratio of constant ratio co-planar electrode constant S / t, and a horizontal distance t to the central position between the electrode plates and electrostatic The characteristic between the capacitance C and the display value Cd is obtained, and the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the inclination information related to the water repellent layer thickness. The intercept b of the display value Cd depending on C obtains an output as initial information related to the moisture content near the surface layer.
At this time, the 20 MHz of the high frequency is not limited to the 20 MHz, and may be an alternating current. However, if the frequency is low, a chemical reaction such as electrolysis of water occurs, and if the frequency is high, a magnetic field can not be generated inside the dielectric, and the magnetic field on the outer surface becomes high. )
Also, although the characteristics of the linear functional equation are preferably linear, they can not be used non-linearly. Therefore, when the simulated water repellent layer 41 formed with a small coating amount is thin, the inclination a may be large, and when it is thick, the inclination a may be small.

Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the simulated water repellent layer 41 formed with a small amount of application is thin, the slope a is large, and when it is thick, it decreases. Therefore, the reciprocal 1 / a of the slope of the regression line of each sample is It can also be expressed as Regarding the relationship between the reciprocal 1 / a of the slope of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.
Therefore, between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, high frequency power is applied to the equal ratio coplanar electrode having a constant equal ratio coplanar electrode constant S / t. The characteristic a of the linear function equation is obtained, and the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the inclination information related to the water repellent layer thickness. The intercept b of b provides an output as initial information related to the moisture content near the surface layer. Thereby, for example, the penetration depth and the like of the silane-based surface impregnated material are measured, and the water-repellent layer thickness of the silane-based surface impregnated material is measured as a regression line.

The horizontal distance t of the equal ratio coplanar electrode constant S / t of the measurement electrode for measuring the difference in the moisture content between the inside of the specimen of the above embodiment and the surface layer portion is the facing average distance d between the opposing electrode plates Since it is made identical, the horizontal distance t where the equal ratio coplanar electrode constant S / t satisfies a constant, and the value obtained by multiplying the horizontal distance t by the circular ratio π are the same as the inter-plate distance d Thus, the electric field draws a circular arc, and the inter-electrode plate distance d can be calculated as a regression line at the center position of the circular arc.
Further, since the inclination of the characteristic of the linear function equation of the above embodiment is the inverse 1 / a of the inclination of the characteristic, the inverse 1 / a of the inclination of the characteristic of the linear function equation is a water repellent layer The inclination information is related to the thickness, and the intercept b of the display value Cd depending on the capacitance C is an output as initial information related to the moisture content near the surface layer.

In the measurement method using a measurement electrode that measures the difference in moisture content between the inside of the test piece of the above embodiment and the surface layer portion, two electrodes of the electrode plate area S are paired, up to the central position between the electrode plates. The equi-coplanar electrode constant S / t of the ratio of the horizontal distance t is constant, except for the case where the areas of the pair of non-coplanar coplanar electrodes are different, and the high-frequency waves on the equi-coplanar electrodes on both sides The characteristic of the linear function equation is obtained between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C by adding the output, and the slope a (reciprocal of the characteristic of the linear function equation Let 1 / a) be inclination information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C obtain an output as initial information related to the moisture content near the surface layer .
With the exception of the cases where the areas of the pair of equal ratio coplanar electrodes are different from those of the equal ratio coplanar electrodes, the electrode plates of the two equal ratio coplanar electrodes even if they satisfy the equal ratio coplanar electrode constant S / t. It means that the areas S are different from each other.

The invention of the measurement method using a measurement electrode for measuring the difference in moisture content between the inside of the specimen of the above-described embodiment and the surface layer portion makes the two electrode plate areas S a pair, and the electrode plate area S and the above The ratio of the horizontal distance t to the center position of the electrode plates The ratio of the same ratio coplanar electrode constant S / t is constant The high frequency output is applied to the equal ratio coplanar electrode, and the horizontal distance t to the center position The characteristic a between the capacitance C and the display value Cd is obtained, and the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the inclination information related to the water repellent layer thickness. The intercept b of the display value Cd depending on the capacity C obtains an output as initial information related to the moisture content near the surface layer.
The display value Cd dependent on the capacitance C is specified, and the water repellent layer thickness is calculated from the specified display value Cd.

  Therefore, when the simulated water repellent layer 41 formed with a small amount of application is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the water repellent layer formed with a small amount of application is thin, the slope a is large, and when it is thick, it is small. Therefore, the reciprocal 1 / a of the slope a of the regression line of each sample is the water repellent layer thickness. It can also be expressed. Regarding the relationship between the reciprocal 1 / a of the slope a of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.

Therefore, between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, a high frequency output is applied to the equal ratio coplanar electrode of which the equal ratio coplanar electrode constant S / t is constant. The characteristic a of the linear function equation is obtained, and the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the inclination information related to the water repellent layer thickness. The intercept b of b provides an output as initial information related to the moisture content near the surface layer. Thus, for example, the penetration depth and the like of the silane-based surface impregnated material were measured, and in the present embodiment, the water-repellent layer thickness of the silane-based surface impregnated material was measured as a regression line.
In particular, the capacitance C is inversely proportional to the facing average distance d between the electrode plates, ie,
C = ε · S / d
When the region of capacitance C is confirmed as a resistor, the measurement electrode for measuring the difference in moisture content between the inside of the sample and the surface layer portion and the measurement method using the measurement electrode are confirmed. be able to.
The display value Cd depending on the capacitance C may be a capacitance C depending on a frequency, or may be simply a capacitance C depending on a frequency.

In the present embodiment, the case of applying the silane-based surface impregnating material has been described, but in the case of carrying out the present invention, the measurement is based on the premise that the silane-based surface impregnating material is not impregnated with water, It can be generally used without being limited to the silane surface impregnation material.
In addition, when water is absorbed by a specimen having a simulated water repellent layer 41 formed in concrete and the condition is similar to that of a two-layer simulated specimen which is the same as the simulated specimen, the reciprocal of the slope of the regression line is A linear relationship was obtained between the and the water repellent layer thickness.
And, according to the experiments of the inventors, the characteristics of the test specimen as the simulated test specimen in advance are gypsum board, concrete, ALA concrete (artificial lightweight aggregate concrete), ALC, mortar, calcium silicate board, D mode, S mode It had to be used as a property. Moreover, when the water repellent layer thickness was estimated by the manufacturer of the surface impregnating material, it showed close values, but there is a possibility that it may be different. It is thought that further examination is needed by changing the

10 Copper foil tape (electrode)
11 Plastic film 12 Polystyrene foam 14 Wrap film 15, 16 Vinyl-coated copper wire 17, 18 Electrode of high-frequency capacitive moisture meter 20 Equi-planar electrode 21, 22, 21A, 22A Electrode plate 31, 32, 33 Simulated water repellent layer 41 Simulated water-repellent layer 42 Simulated non-water-repellent layer t Horizontal distance d Countering average distance S between opposing electrode plates Electrode plate area C between opposing electrode plates Capacitance ε Dielectric constant S of dielectric between electrodes t equal ratio coplanar electrode constant

The present invention relates to a measurement method for measuring the difference in moisture content between the inside of a sample and the surface layer portion of the thickness of a water repellent layer coated on a concrete surface, for example, a measurement method capable of measuring the thickness of the water repellent layer It belongs to.

For example, in the case of blending concrete aggregate, it is assumed that the surface is in a “surface dry state (surface dry saturated state)”, the density of the aggregate is determined, and blending is performed according to various blending designs. Here, the "surface dry state" is based on the premise that the internal space of the compacted aggregate is filled with moisture, and the surface of the aggregate is free of moisture. .
Generally, the flow cone method standardized in JIS A1109 is employed to determine the surface dry state of aggregate. According to this, the aggregate is filled into a frustoconical flow cone, and the end is pressed to a predetermined hardness by pushing with a push rod, and then the flow cone is gradually pulled upward and the pressed bone is compacted. The condition near the boundary whether the material collapses or does not collapse is judged as the surface dry condition.

However, these determinations of surface dryness require accurate data in which the aggregate is broken. In particular, heuristics are needed to make accurate decisions. Therefore, an unaccustomed measurer may not be able to make an accurate judgment.
In particular, the flow cone method described above is mainly applied to sand, gravel, etc. called “natural aggregate”, but in recent years, the supply amount of this “natural aggregate” has decreased, and Alternatives are used as aggregate. For example, so-called "low grade" aggregates such as crushed sand, blast furnace slag, refuse melting slag, recycled aggregate and the like are widely used. These low-grade aggregates may exhibit vitreous or porous properties on their surfaces, and may have surface-drying characteristics which are clearly different from those of natural aggregates. Therefore, in the flow cone method, it is particularly difficult to determine an accurate surface dry state for aggregates such as crushed sand.
For example, a method of using a new standard surface dry judgment cone formed by a size such as a self-supporting angle or a wide diameter different from the shape of a flow cone standardized by JIS, the moisture content is measured using infrared reflectance The thing (refer nonpatent literature 1), the thing using change of electric resistance in a wet and dry state (refer nonpatent literature 2), the thing using centrifugal dehydration method (refer nonpatent literature 3), etc. are known.

Takeuchi, Kazuma, 3 others "Basic research on surface dry judgment test method of fine aggregate", Annual Proceedings of Concrete Engineering, Vol. 25, No. 1, 2003, p77-p82 Daisuke Yamamoto, 4 others "Consideration on the method for determining the surface dryness of crushed sand as sand and sand substitute aggregate", 59th Annual Conference of the Japan Society of Civil Engineers, September, 2004, p491-p492 Kazuo Suzuki, 1 other person “A study on simple method for determination of fine aggregate by surface dry”, Proceedings of the 48th Cement Technology Conference, 1994, p156-p159 JP, 2006-329801, A

Non-Patent Document 1 uses flow cones formed by different self-supporting angles and sizes, and a certain degree of empirical rule is required for the determination of the surface dry state as in the prior art, and accurate repeatability is sought. It was difficult. Moreover, it was necessary to select the optimal flow cone suitably according to the kind and property of aggregate, and it was necessary to prepare multiple types of flow cone in advance.
In particular, those utilizing the reflectance of the infrared non-patent document 1 is generally a is absorbed into the water easily infrared wavelengths (1.46 .mu.m), the two kinds of wavelengths less likely to be absorbed in water infrared wavelengths (1.6 [mu] m) Since it was used and was calculated by the data measured mainly for "Shirasu" as aggregate, it was not disclosed about the effect | action with respect to another low grade aggregate.
In Non-Patent Document 2, various measurements are carried out using crushed sand as a sample to be measured, and by combining various results, the result that the flow cone method has the most appropriate result can be obtained, and the other methods are not. The measurement results of Patent Document 2 did not show particularly excellent characteristics.
And in Non-Patent Document 3, although it becomes possible to judge the surface dry state with high accuracy, the target aggregate is set in the centrifugal separator, and the centrifugal force of several G to several G according to the sample In some cases, the apparatus for determining the surface dry state is bulky and is not suitable for simple determination of the surface dry state.

On the other hand, for the improvement of the durability of the present concrete structure, a method of applying a silane-based surface impregnating material to the surface and permeating the surface, and forming a water repellent layer inside the concrete has attracted attention.
By applying the water repellent layer, the penetration of water can be suppressed, and the penetration of deterioration factors of the concrete such as salt and water can be suppressed, whereby the durability of the concrete can be enhanced. For example, “Hokkaido Development Bureau Road Design Guidelines” stipulates that the penetration depth is 6 mm or more in the measures against frost damage as a standard of product selection of silane-based surface impregnation material.
However, in order to confirm the thickness of the applied water repellent layer, there is a method of drilling in concrete and observing. This method of drilling in concrete would damage the construction product and was not necessarily the preferred method. Then, although it is managed by application amount from the relationship between the application amount to the test object produced beforehand, and the water-repellent layer thickness, the construction actual condition is unknown.
The water repellent layer thickness formed by the surface impregnating material is reported to be affected by the moisture content of concrete. The higher the moisture content, the smaller the penetration depth. At the construction site, the moisture content may be different depending on the location due to the influence of rainfall or solar radiation. For this reason, it is also conceivable that the water repellent layer thickness at the site may cause an error from the estimated value by the amount applied to the sample. Moreover, when apply | coating to the existing concrete structure, the test body produced separately does not remain in many cases, and it can not obtain | require the relationship between the application quantity to a test object, and the water-repellent layer thickness.
From such a thing, when applying a surface impregnation method, the quality of construction can be enhanced by managing with the formed water repellent layer. Therefore, the present inventors have investigated a method of estimating the water repellent layer thickness of concrete using electrical changes due to the water content ratio.

 Therefore, the present inventors have provided a method of determining the surface dry state of aggregate with a relatively simple configuration in Patent Document 1 That is, this is mixing and stirring water in the aggregate in the bone-drying state, and mixing and stirring the water in the aggregate in the bone-drying state and the reference sample preparation step of preparing each to a predetermined moisture content respectively The ionized sample preparation step of preparing an ionized substance having conductivity and adding the ionized material having conductivity and stirring the mixture, and a plurality of reference samples having different water contents prepared by the reference sample preparation step and the ionized sample preparation step And filling the plurality of ionized samples having different moisture contents prepared in the above into the measurement container having a predetermined shape and smoothing the sample surface, and the reference sample filled in the measurement container. And a measurement step of measuring a high frequency capacity by bringing a measurement portion of the high frequency capacity moisture meter into contact with the surface of the sample of the ionized sample, and the high frequency capacity moisture meter A reference sample indicating the relationship between the indicated value and the moisture content of the reference sample or the ionized sample, and the addition sample are prepared, and a surface dry point at which the inclination of the addition sample changes with respect to the reference sample It comprises the table dry judging process which specifies and judges the surface dry state.

Thereby, the moisture meter which measures the moisture content of concrete is improved, and the electric field generated from the electrode plate reaches the concrete by changing the distance between the pair of electrode plates by measuring the capacitance. When the electric field is in the water repellent layer, the capacitance decreases at a constant rate, and when the electric field reaches the high water content simulated non-water repellent layer, the rate of decrease in capacitance changes. The inflection point is defined as the boundary between the water repellent layer and the ordinary layer, and a value relatively close to the measured value is obtained.
However, in the water containing concrete of Patent Document 1, pure H ₂ O is a good insulator, and when the pure H ₂ O is measured, the resistance decreases during the measurement. Also, along with that, the dielectric constant also changes depending on the metal ion, and changes as the frequency characteristic of conductivity and dielectric constant depending on the water content. Also, if the measurement target is a large volume, the electric field spreads and the electric field density changes depending on the position of the electrode plate, the area of the electrode plate, and the height of the applied voltage that determines the electric field. Calculation will be needed.

Therefore, the present invention aims to provide a measurement method which can measure the thickness of the water repellent layer without the effect appearing even if the resistance value and the dielectric constant change depending on the water content without changing the result depending on the water content. It is said that.

The measurement method which can measure the thickness of the water repellent layer of the invention of claim 1 is that the electrode plate area S and the horizontal distance t to the center position between the electrode plates are a pair of two electrode plates having the electrode plate area S The equal ratio coplanar electrode constant S / t of the ratio to each electrode plate area S is constant , and it is composed of a plurality of electrodes having different electrode areas. A high frequency output is applied to both sides of a pair of equal ratio coplanar electrodes, and the capacitance C is measured. A characteristic of a specific linear function is obtained between a horizontal distance t to the center position of the electrode plates and a display value Cd measured at each electrode depending on the capacitance C, and a slope a of the characteristic of the linear function Is the inclination information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is output as initial information related to the moisture content near the surface layer.

Here, the equal ratio coplanar electrodes, the ratio of horizontal distance t and the electrode plate area S of the specimen to the center position of the electrode plates mutually may be a constant. In particular, it is the isometric coplanar electrode constant S / t that satisfies it. (However, even if the geometrical ratio coplanar electrode constant S / t is the same, except for the case where the pair of electrode plate areas are different.)
Further, the horizontal distance t of the above-mentioned equal ratio coplanar electrode constant S / t can be made equal to the facing average distance d between the facing electrode plates on the linear distance. However, it is preferable that the horizontal distance t and the facing average distance d be the same because they are determined by the electrostatic field and the electric field, and they should be offset by a calculation formula.
The slope of the characteristic of the linear function can be the slope of the characteristic or the reciprocal 1 / a of the inclination of the characteristic. In any case, a high frequency output is applied to the equal ratio coplanar electrodes on both sides of a fixed equal ratio coplanar electrode, and the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C The characteristics of the linear function may be drawn between the two.

The invention of the measuring method capable of measuring the thickness of the water repellent layer according to claim 1 makes two electrode plates of the electrode plate area S a pair and measures the horizontal distance t between the electrode plate area S and the center position of the electrode plates. High frequency output is applied to equal ratio coplanar electrodes except for the case where the ratio of the ratio to that of the constant ratio coplanar electrode constant S / t is constant and the area of the pair of equal ratio coplanar electrodes is different, and the center position between the electrode plates Obtain a characteristic between the horizontal distance t of the surface and the display value Cd depending on the electrostatic capacitance C, and let the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation be the inclination information related to the water repellent layer thickness Further, the intercept b of the display value Cd depending on the capacitance C obtains an output as initial information related to the moisture content near the surface layer.

Therefore, when the water repellent layer formed with a small coating amount is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the water repellent layer formed with a small amount of application is thin, the slope a is large, and when it is thick, it decreases. Therefore, the reciprocal 1 / a of the slope of the regression line of each specimen is expressed as the water repellent layer You can also Regarding the relationship between the reciprocal 1 / a of the slope of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.
Therefore, between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, a high frequency output is applied to the equal ratio coplanar electrode of which the equal ratio coplanar electrode constant S / t is constant. The characteristic of the linear function equation is obtained, and (reciprocal number 1 / a) of the inclination of the characteristic of the linear function equation is the inclination information related to the water repellent layer thickness, and the display value Cd depending on the capacitance C The intercept b of b provides an output as initial information related to the moisture content near the surface layer. Thereby, for example, the penetration depth and the like of the silane-based surface impregnated material are measured, and the water-repellent layer thickness of the silane-based surface impregnated material is measured as a regression line.

FIG. 1 is a basic explanatory view illustrating a measuring method capable of measuring the thickness of the water repellent layer according to the embodiment of the present invention. FIG. 2 is a basic block diagram of the embodiment of the present invention. FIG. 3 is an explanatory view showing the relationship between the water content used in the embodiment of the present invention and the display value in the case where the simulated non-water repellent layer is constant. FIG. 4 is a characteristic diagram showing the relationship between the horizontal distance and the display value according to the simulated specimen used in the embodiment of the present invention. FIG. 5 is an explanatory view showing the relationship between the slope and the intercept of the regression line used in the embodiment of the present invention. FIG. 6 is a characteristic diagram showing the relationship of the intercept at each moisture content used in the embodiment of the present invention. FIG. 7 is a characteristic diagram showing the relationship of the reciprocal of the slope in each moisture content used in the embodiment of the present invention. FIG. 8 is an explanatory view showing the composition of the concrete sample to be measured in the embodiment of the present invention. FIG. 9 is an explanatory view showing the physical properties of the aggregate of the concrete sample to be measured in the embodiment of the present invention. FIG. 10 is a characteristic diagram showing the change of the capacitance of the concrete sample to be measured in the embodiment of the present invention. FIG. 11 is a characteristic diagram showing the reciprocal of the inclination and the water repellent layer thickness measured in the embodiment of the present invention. FIG. 12 is a characteristic diagram of the display value of the test sample of stationary day 1 having the inclined water content distribution measured in the embodiment of the present invention. FIG. 13 is a characteristic diagram of the display value of the specimen of stationary 7 days having the inclined water content distribution measured in the embodiment of the present invention. FIG. 14 is a measurement result diagram showing measured values and estimated values measured in the embodiment of the present invention.

Hereinafter, the measuring method which can measure the thickness of the water repellent layer of embodiment of this invention is demonstrated based on drawing. Note that, in the embodiment, the same symbols and symbols in the drawings are the same or corresponding functional parts, and therefore the description thereof will not be repeated here.

Embodiment
First, the basic principle of the measurement method capable of measuring the thickness of the water repellent layer will be described.
In the present invention, a pair of electrodes is a parallel plate, and the configuration of a capacitor in which a dielectric of dielectric constant ε is sandwiched therebetween is used. The electrode plate area S of the parallel electrode plates is in the state of being disposed apart by the facing average distance d between the electrode plates opposite to each other in parallel. The capacitance C of the electrode plate of the electrode plate area S at this time is proportional to the dielectric constant ε of the dielectric between the electrode plate area S and the electrode plate, and the capacitance C of the electrode plate is S The capacitance C is expressed by the following equation.
C = ε · S / d
Where C (F) capacitance
S (m ² ) Electrode plate area between facing electrode plates
d (m) opposing average distance between opposing electrode plates
ε (F / m) is the dielectric constant of the dielectric between the electrode plates.

As the high frequency source, since the inventors are used to handling, a commercially available high-frequency capacitive moisture meter (HI-520: manufactured by Ketto Scientific Research Institute, Inc., high-frequency capacitive type (20 MHz)) electrodes 17 and 18 The high frequency output from was used.
In the experiments of the inventors, a high-frequency capacitive moisture meter is used instead of the LCR meter, but as a result, the value of the capacitance C is not measured, but the output is relayed. The capacitance C of the test material (aggregate) is not calculated based on the dielectric constant ε at a high frequency (20 MHz).
If a general LCR meter is used, it is necessary to consider the influence of stray capacitances of the electrodes 17, 18, etc. As a result, it is considered that a commercially available high frequency capacitive moisture meter is more useful.

First, when water is included in the aggregate of the test material, a phenomenon occurs in which the capacitance C increases with the increase of water. Usually, when the capacitance C is calculated from the dielectric loss tangent tan δ,
It is expressed by the current Ir of the resistance component / the current Ic of the capacitor capacitance component, and the equation is
tan δ = Ir / Ic
It becomes.
However, the dielectric constant of about 80 of water changes with the change of temperature and also changes with the frequency applied, and a chemical reaction occurs and also changes with the application time and the like. This is largely due to the action of melting by ions and the like.
Moreover, although the electrostatic capacitance C is calculated as C = (epsilon) * S / d, the area | region pinched | interposed between electrodes can also be caught as a resistor.
Therefore, as the phenomenon, when the aggregate of the test material is made to contain water, the capacitance C increases with the increase of water, so it was decided to capture only that event.
The amount of increase in capacitance C as the water content increases is converted in accordance with a conversion formula previously obtained using mortar, concrete, and various other test materials, and is displayed as the water content. Here, in the test material having no conversion formula, the mode is switched to the direct mode (D mode) of a commercially available high-frequency capacitive moisture meter, and a numerical value correlated with the capacitance C is displayed as a display value Cd. As a precaution, the display value of the direct mode used by the inventors is displayed between "0 and 2999".

A high frequency output (AC voltage) was applied to both electrode plates, and a band-like electric field was generated therebetween, and the capacitance C of the test material on this electric field was measured. The shape of the electric field is considered to be arc-like or elliptical depending on the boundary conditions etc. However, "It is possible to evaluate the amount of dielectric physical properties to the depth proportional to the electrode spacing ( Since it is said that “Development diagnosis technology for polymer electrical insulation materials” (FY 2004-2006 Grant-in-Aid for Scientific Research Grants Report), the opposing average distance d between the electrode It was assumed that it was a circular arc shape that was simply proportional. The electrode plates were arranged in parallel so that the electric field was transmitted through the test material, and it was assumed that the depth at which the electric field reached would be changed by changing the facing average distance d between the electrode plates .

Further, the dielectric constant ε of the dielectric changes in accordance with the water content. Further, the facing average distance d between the electrode plates is the facing average distance length of the arc-like electric field. When the facing average distance d between the electrode plates is small, the electric field exists only in the simulated water repellent layer 41, and the capacitance C decreases with the increase in the facing average distance d between the electrode plates. When the electric field reaches the simulated non-water repellent layer 42 having a high water content, the dielectric constant ε also changes, and the reduction rate of the display value Cd changes.
Therefore, logically, this inflection point is the boundary between the simulated water repellent layer 41 and the simulated non-water repellent layer 42. The estimated value of the water repellent layer thickness at this time was close to the confirmed value confirmed by the measurement. However, if the simulated water repellent layer 41 is thin, an inflection point appears immediately, which makes it difficult to determine the inflection point. In addition, when the width of the electrode plate is narrowed for thin water-repellent layer thickness measurement, there is a disadvantage that the accuracy is lowered. That is, it is estimated that the electric field affects the side of the non-water repellent layer 42 from the beginning.

Next, the electrode plates 21, 22, 21A, 22A shown in FIG. 1 used in the embodiment of the present invention will be examined.
An electrode was manufactured such that the ratio S / t of the horizontal plate distance t from the center position of one electrode plate to the center position of the other electrode plate and the electrode plate area S was constant. An electrode in which the ratio S / t of the horizontal plane distance t to the electrode plate area S is constant is referred to as a "equal ratio coplanar electrode". Further, although the horizontal distance t is defined for the electrode plates 21, 22, 21A, 22A, it may be a vertical surface or may have a predetermined inclination. Here, in order to clarify the difference with the facing average distance d between electrode plates, it is called horizontal surface distance t. Here, S / t = const is referred to as "equal ratio coplanar electrode constant".

Here, a value obtained by multiplying the horizontal distance t by the circle ratio π is set as the facing average distance d between the electrode plates .
π · t = d
t = d / π
It becomes.
Therefore,
S / t = S · π / d
It becomes. The circle ratio π is constant, and the uniform coplanar electrode constant S / d is always constant.
In addition, the capacitance C is constant, if the dielectric constant ε, that is, the water content does not change in the depth direction, according to C = ε · S / d.
Then, when the horizontal distance t is sequentially increased, when the electric field reaches a portion with high water content, the capacitance C changes for the first time, and the value of the changed position becomes the depth of the simulated water repellent layer 41 .

The inventors further investigate iso-coplanar electrodes 21, 22, 21A and 22A (hereinafter, these will be collectively referred to as “e-coplanar electrode 20”).
Five types of equal ratio coplanar electrodes 20 having horizontal surface distances t of 4, 8, 12, 16, and 20 mm were produced. The electrode plate length of the equal ratio coplanar electrode 20 was constant at 100 mm, and the electrode plate width was changed to set the equal ratio coplanar electrode constant S / t = 100. In this case, since the width of the electrode plate offsets the horizontal distance t, the facing average distance d between the electrode plates and the horizontal distance t of the equal ratio coplanar electrode 20 are the same (the facing average distance d between the electrode plates d = horizontal distance t) And Here, electrode plates having different areas of the pair of equal ratio coplanar electrodes 20 were excluded.

As a material of an electrode plate, as shown in FIG. 2, the copper foil tape 10 was stuck on the plastic film 11, and also the plastic film 11 was stuck on the polystyrene foam 12 of 25 mm. Vinyl coated copper wires 15 and 16 were attached to the copper foil tape 10 as an electrode plate and extended, and brought into contact with the electrodes 17 and 18 of a commercially available high-frequency capacitive moisture meter. Although the lengths of the vinyl-coated copper wires 15 and 16 as lead wires are different in FIG. 2, they are uniform in length in the test circuit. The circuit has symmetry and is drawn out on the opposite side.
In particular, when both vinyl coated copper wires 15 and 16 are brought close to each other, they are influenced by the electrostatic stray capacitance and affect the displayed value Cd of the output, so they are separated from each other so that the influence becomes the minimum value. In order to electrically connect only the upper surface of the electrode 21A (21) and the electrode 22A (22) to the upper surface of the simulated sample, a wrap film 14 is applied to electrically insulate the other upper surface of the simulated sample.
Also, a 2 kg weight 13 was placed on the polystyrene foam 12 in order to bring the copper foil tape 10 into close contact with the test piece.

Using the equal ratio coplanar electrode 20 manufactured in this manner, a simulated specimen with a constant water content was manufactured, and the characteristics of the display value Cd of the carbon plate and the concrete were measured. A caikale plate is easily processed at a thickness of 5 mm, has a high water absorption rate, and has a high water absorption rate, and was adopted as a simulated specimen.
A sample of 5 mm in thickness x 100 mm in length x 100 mm in width is subjected to oven drying at 105 ° C. for 24 hours to obtain a water content of 0%. The sample was placed in a plastic bag with water of such a mass as to cause water absorption, and was then absorbed to make a sealed test sample. Then, as shown in FIG. 3, a caical plate having a moisture content of 0, 6, 12% when the whole of the simulated specimen was 100% was manufactured. In addition, concrete manufactured cubes with a moisture content of 0, 4 and 6.4%.

Here, since the bone dry plate has an absolute dry density of about 0.7 g / cm ³ , which is about 1/3 of that of concrete, the amount of water containing water is about 1⁄3 of that of concrete with the same water content. Eight equal carbon content plates having the same water content were stacked to prepare an equal ratio coplanar electrode 20, and the value of the display value Cd was measured.
The concrete was prepared by cutting a 100 × 100 × 400 mm concrete simulation specimen prepared with a 55% water / cement ratio into cubes of 100 mm square and saturated with water to obtain a surface dry state (water content: 6.4%) What was adjusted so that the moisture content and the moisture content of the same dimensions as that of the one were adjusted to 4.0% and 0% was put in a plastic bag and sealed, and water was uniformly adsorbed to obtain a simulated specimen of a predetermined moisture content.
Here, the relationship between the horizontal distance t of the simulated specimen and the display value Cd is shown in FIG.

As shown in FIG. 3, it can be seen that the display value Cd is substantially constant even if the horizontal surface distance t is changed, if the water content of the concrete and the carbon plate is constant. Once the indicated value Cd and the specimen such as concrete or caulcal plate are known, the moisture content of the specimen is specified. Here, it is presumed that the error of the indicated value Cd is due to the difference in the characteristic of the moisture content distribution to the caulcal board and the general relation of the concrete, and the difference in the moisture content depending on the individual.
In addition, even if the horizontal distance t to the electrode plate center position at each moisture content increases, it is confirmed that the value of the display value Cd does not change and becomes substantially constant even if the horizontal distance t decreases.
Then, if the equi-coplanar electrode constant S / t is constant, the dielectric constant ε (water content) changes even if the horizontal distance t to the electrode center position is increased and the position where the electric field reaches is deepened. If not, the display value Cd is the same value. Then, the result was obtained that the value of the display value Cd becomes larger as the moisture content becomes higher. From this, it can be seen that the indicated value Cd depends on the water content.

Next, measurement of the simulated specimen of the simulated water repellent layer 41 is performed using this equal ratio coplanar electrode 20.
1 or 2 or 3 sheets of 0, 6 and 12% silicon plates are placed on the concrete cubes with water content of 6.4% and 4.0% shown in FIG. 2 and FIG. 3, and lamination of each electrode plate The display value Cd was measured in the state. The carbon plate is a two-layer simulated specimen model in which the simulated water repellent layer 41 having a low water content is simulated, and the concrete non-water repellent layer 42 having a high water content is simulated.

As shown in FIG. 4, one, two, three, or four pieces of silicon boards with a moisture content of 0% are stacked on concrete having a dielectric constant ε and a moisture content of 6.4%, and the horizontal distance t to the electrode plate center position and each display The relationship of the value Cd is illustrated.
As shown in FIG. 4, the inclination of the straight line is large when the thickness of 5 mm of the silicon plate is as thin as one, and the inclination is small when the thickness of three laminated sheets is 15 mm.
Further, the intersection point of the y-axis intersecting the y-axis at x = 0 which does not depend on the thickness of the caiscal plate, that is, the intercept b of the display value Cd is substantially the same value. The value showed a value close to the indicated value Cd = 1270 in the case of overlapping the silica plates having a water content of 0% shown in FIG. A linear relationship, ie, a linear function equation of the display value Cd, is also used in the case of using a calcium carbonate of other moisture content
Display value Cd = ax + b = ax + 1270
The display value Cd is the vertical axis (y), and x is the horizontal axis.
was gotten. The intercept b of the indicated value Cd is shown in FIG.
The slope of each straight line obtained by linear regression of the relationship between the display value Cd and the horizontal distance t obtained by changing the moisture content of concrete and caycal board and the number of stacked caical boards and changing it. An intersection point of a and x = 0 y axis (display value Cd) is a display value Cd.

The larger the difference between the moisture content of the cical plate regarded as the simulated water repellent layer 41 and the moisture content of concrete regarded as the simulated non-water repellent layer 42, the larger the inclination of the regression line. It is considered that if the impedance of the capacitance Ca of the caical plate and the impedance of the capacitance Cb of concrete are considered to be connected in series, when Ca 接 続 Cb by the comparison of impedances, the capacitors are connected in series The amount of work is dependent on Ca, which has a large capacitance impedance.
In particular, when the moisture content of concrete is 4% and the moisture content of the cical plate placed above is 12%, the difference between the moisture content of the two is not so large, the inclination becomes negative when the number of cical plates is increased. , The correlation coefficient of the regression line also decreases.
In addition, when the thickness of the simulated water repellent layer 41 was large, that is, as the number of the silica plates was increased, the inclination was reduced. In the case where the moisture content of the caycal plate is the same, as shown by the relationship between the moisture content and the segment shown in FIG. 6, the values of the segment b become substantially the same even if the number of overlapping sheets is changed. In particular, since the water content is constant and there is no change in the water content, it is estimated that the same can be obtained regardless of how many sheets are used.
Also, it is considered that the simulated water repellent layer 41 is a desirable measurement method because the moisture content is very small.

In addition, in the case of three caical plates (15 mm thick), the display value Cd does not change with electrodes having a horizontal distance t of 4 mm and 8 mm, so the electric field has a large effect on the simulated non-water repellent layer 42 with high moisture content It is presumed that there is no
Although it was estimated that the display value Cd would increase rapidly at 12 mm and 16 mm or more starting to reach the simulated non-water repellent layer 42, the display value Cd would increase continuously and a linear relationship was obtained between the horizontal distance t and the display value Cd. No continuous points occurred. The electric field shape is also presumed to be an arc when the electrode plates face each other in the opposite state, but the electric field in the sample is the same as the sum of the capacitances as impedances connected in series between equal ratio coplanar electrodes 20. Detailed analysis, such as investigation of the influence of the difference in the shape of the water content and the moisture content, will be the subject for future study.

The moisture content of the caking plate piled up at 6% and 4% of the concrete content, the reciprocal of the slope 1 / a of the regression line obtained by changing the thickness of the caking plate with 0% and 12%, respectively The relationship with the thickness of the caycal plate is shown in FIG. The linear relationship which can be shown by a linear function equation was obtained for the reciprocal 1 / a of the slope and the thickness of the caycal plate, respectively.
From this, if the relationship between the reciprocal 1 / a of the slope and the thickness of the water repellent layer is determined in advance for each sample, the regression line of the horizontal distance t and the display value Cd obtained by measuring with the equal ratio coplanar electrode 20 The water repellent layer thickness can be estimated from the slope a or the reciprocal 1 / a of the slope.

Next, it examines using the day of these obtained mock specimens.
First, a concrete simulation sample on which a simulation water repellent layer 41 was formed was measured with a uniform ratio coplanar electrode 20, and the reciprocal 1 / a of the slope of the regression line as obtained for the simulation sample and the water repelling layer thickness Examine the relationship.
The concrete used three types of compounding. The composition of the concrete and the 28-day compressive strength are shown in FIG.
The water to cement ratio (referred to as W / C in FIG. 8) was 40, 55, 70%. Relatively low quality such as ordinary concrete with 55% water / cement ratio and 5% air content, which are used in general structures, and 40% water / cement ratio assuming relatively high strength The amount of air can be reduced without using an AE agent (a type of surfactant, an additive that improves the efficiency of concrete placement and the freeze resistance) at a low water-cement ratio of 70% assuming concrete. It was decided to be. The cement used was early-strength cement.
The physical properties of the used aggregate are shown in FIG. The coarse aggregate used grated stone from Nagara River, and the fine aggregate was a mixture of coarse sand and fine sand from Nagara River at a ratio of 7: 3.
Here, s / a is a fine aggregate rate (the ratio of the volume of the fine aggregate to the volume of the total aggregate), and in this case, s / a = 40%. Moreover, S1 is a coarse thing among fine aggregates, S2 is a fine thing among fine aggregates, G is a coarse aggregate.

As shown in FIG. 8, two types of curing were used: curing in water and curing in air for 28 days after demolding.
A specimen of a square column of 100 mm × 100 mm × 400 mm was prepared, and after curing, it was cut using a concrete cutter to make 50 mm × 100 mm × 130 mm. After making a bank on a 100 mm × 130 mm cut surface so that the surface impregnating material does not drip on the side surface of the sample, it was dried in an oven to be completely dried, and further, the surface impregnating material was applied.
The surface impregnating material is manufactured by TOOKEN CHEMICAL CO., LTD. (Product name S-7; hereinafter simply referred to as "made by T company") and Daido Paint Co., Ltd. (product name aqua seal 1400; hereinafter referred to simply as "made by company D") Was used. The product of company T is liquid, and the product of company D is gel.
Both of the components were silanes, and the standard amount used was 200 g / m ² . The coating amount was set to ^{100g / m 2 ~500g / m 2} , a portion of the specimen number was applied 50 and 800 g / m ^2. The number of specimens was 68 in all.

After leaving for 4 days or more after application so as to form the simulated water repellent layer 41, the sample was placed in a container and immersed in water. The depth of water was set to the height of the specimen, and water was allowed to absorb from the bottom and the side of the specimen for 4 days. The simulated water repellent layer 41 has a very low water absorption rate, and the simulated non-water repellent layer 42 has a high water absorption rate, so the simulated water repellent layer 41 has a small water content like the simulated sample and the simulated non water repellent layer has a high water content. Forty-two two-layer specimen models were constructed.
Fig. 10 shows that 100, 300, 500 g / m ² of surface impregnated material from T Co. is applied to those cured in water at a cement ratio of 55% with water, but the horizontal distance t to the electrode plate center position and the indicated value Cd Show the relationship between It shows that a linear relationship (linear characteristic) can be obtained in the display value Cd depending on the horizontal distance t to the electrode plate center position and the capacitance C as in the case of the simulated specimen.
After the measurement, each sample was split and the actually formed water repellent layer thickness was measured. The measurement averaged the value in the center part and the part of the position of 25 mm on both sides. When the simulated water repellent layer 41 formed with a small coating amount is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b has substantially the same value, and the water content of the water repellent layer portion is considered to be the same.
The coating amount of the surface impregnating material is 100, 300 and 500 g / m ² , but the inclination a is large when the water repellent layer formed with a small coating amount is thin, and is small when it is thick.
In this way, the slope a is obtained as a linear function of the relationship between the display value Cd measured by the electrode shown in FIG. 10 and the distance t to the center of the electrode. As in the case of 4.8 mm, 10.2 mm and 14.0 mm in FIG. 10, the sample is divided to obtain the actual water repellent layer thickness.

Furthermore, FIG. 11 shows the relationship between the reciprocal 1 / a of the slope of the regression line of each simulated specimen and the measured value of the water repellent layer thickness.
The Y axis in Figure 11 uses the water repellent layer thickness actually measured by dividing the sample, and the X axis uses the reciprocal 1 / a of the slope a to obtain a linear function.
As a formula,
The water repellent layer thickness is 164.5 × (1 / a) + 1.302.
If the sample whose water repellent layer is unknown is measured with an electrode and the inclination a is obtained, the water repellent layer can be determined from this equation.
In FIG. 11, the number of test specimens is 68, which is the sum of simulated test specimens coated with T company and D company. The reciprocal 1 / a of the slope is confirmed from the water repellent layer thickness X measured by making the reciprocal 1 / a of the slope of each simulated specimen and the intercept b of the measured value of the water repellent layer common to the indicated value Cd. Be done.
Therefore, the reciprocal 1 / a of the slope is determined from the straight line of the linear function equation expressed by the 68 data, and if the reciprocal 1 / a of the slope is identified, the water repellent layer thickness is identified.
A linear relationship was obtained for the reciprocal of the slope and the water repellent layer thickness as in the case of the simulated specimen. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.

Next, a measurement method capable of measuring the thickness of the water repellent layer assuming an actual structure will be described.
In the sample described above, the simulated water repellent layer 41 has a low moisture content, and the simulated non-water repellent layer 42 has a two-layer sample model with a high moisture content close to the surface dry state.
However, in an actual structure, the water content is not a two-layer sample model, but is estimated to be a slope distribution in which the vicinity of the surface is low and the height gradually increases toward the center. Assuming a slope distribution, the prismatic specimen cured in water at a cement ratio of 55% with water is divided into two equal parts, and those sealed with a rubber-based paint to prevent entry and exit of water except for the cut surface are immersed for 3 days, It stood still in the laboratory for 7 days and 1 day. Two of them were allowed to stand.
The seven-day Gifu Meteorological Observatory records that this test was conducted showed an average temperature of 6.3 ° C and an average humidity of 62%. After standing, 200 g / m ^{2 of a} surface impregnating material manufactured by D was applied to the cut surface. The indicated value Cd was measured with the electrode before application and 4 days after application.
After the measurement, it was split to measure the simulated aqueous layer depth. The relationship between the horizontal distance t to the electrode center before application and after application and the display value Cd is illustrated.

As for what was dried for 1 day, as shown in FIG. 12, the display value Cd before application becomes a value close to the display value Cd = 1900 of the surface dry state (water content 5.2%) even when the horizontal distance t is 4 mm. Most of the water is not evaporated, and it is presumed to be in a saturated state. Although the indicated value Cd decreased even after the application, it was an almost constant value and a clear slope was not obtained, and the water repellent layer thickness could not be estimated.
The estimation of the water repellent layer thickness in a moisture content distribution with a slope assuming an actual structure may have few experimental examples and may need to be corrected in the future. In the future, it is necessary to further study, such as changing the moisture content.

In addition, as shown in FIG. 13, the display value Cd before application is as low as 1900 at a horizontal distance t of 4 mm, the display value Cd is as low as 1900, and is substantially the same for 8 mm or more. It has become. The indicated value Cd at 8 mm or more is a value close to the indicated value of the concrete in the surface dry state (water content: 6.4%) shown in FIG. 3, and it is considered that the inside is saturated.
After application, the display value Cd decreased at 4, 8 and 12 mm, and became a value close to the value before application at 16 mm or more. Linear regression was performed using the value up to 16 mm at which the increase in the display value Cd after application almost disappeared, and the slope a was determined. An estimated value and an actual measurement value obtained by estimating the water repellent layer thickness from the relationship between the inverse 1 / a of the slope and the water repellent layer thickness using the slope a are shown in FIG. The estimated value and the measured value show relatively close values.

The measurement method which can measure the thickness of the water repellent layer of the above embodiment is the same ratio coplanar electrode constant of the ratio of the horizontal distance t to the center position of the electrode plates with two sheets of the same electrode plate area S as a pair. A high frequency is applied to the equal ratio coplanar electrodes 20 and the equal ratio coplanar electrodes 20 on both sides except that the S / t is constant and the areas of the pair equal ratio coplanar electrodes are different from each other, and the central positions of the electrode plates A linear function equation Y = aX + Cd characteristic is obtained between a horizontal surface distance t up to and a display value Cd depending on a capacitance C based on high frequency, and a slope a of the characteristic of the linear function or a reciprocal 1 / a An output is obtained as inclination information related to the layer thickness.
Here, by measuring gypsum board, concrete, ALA concrete (artificial lightweight aggregate concrete), ALC, mortar, calcium silicate board, D mode, S mode characteristics, as initial information related to the moisture content near the surface layer An intercept b of the display value Cd is calculated.
Further, if the reciprocal 1 / a of the slope in the characteristic of the linear function equation is the inclination information related to the water repellent layer thickness, and if the reciprocal 1 / a of the inclination of the characteristic of the known linear function equation is set as a standard In addition, if the point at which the display value Cd dependent on the capacitance C matches is determined, the water repellent layer thickness can be calculated.

In the measurement method which can measure the thickness of the water repellent layer of the above embodiment, the two electrode plate areas S are a pair, and the ratio of the electrode plate area S to the horizontal distance t to the center position between the electrode plates is For example, a high frequency output of 20 MHz is added to the equal ratio coplanar electrode having a fixed equal ratio coplanar electrode constant S / t, and the display value Cd depending on the horizontal distance t to the center position between the electrode plates and the capacitance C And the slope a (reciprocal number 1 / a) of the characteristic of the linear function equation as the slope information related to the water repellent layer thickness, and the intercept of the display value Cd depending on the capacitance C b obtains an output for obtaining an output as initial information related to the moisture content near the surface layer.
At this time, the 20 MHz of the high frequency is not limited to the 20 MHz, and may be an alternating current. However, if the frequency is low, a chemical reaction such as electrolysis of water occurs, and if the frequency is high, a magnetic field can not be generated inside the dielectric, and the magnetic field on the outer surface becomes high .
Also, although the characteristics of the linear functional equation are preferably linear, they can not be used non-linearly. Therefore, when the simulated water repellent layer 41 formed with a small coating amount is thin, the inclination a may be large, and when it is thick, the inclination a may be small.

Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the simulated water repellent layer 41 formed with a small amount of application is thin, the slope a is large, and when it is thick, it decreases. Therefore, the reciprocal 1 / a of the slope of the regression line of each sample is It can also be expressed as Regarding the relationship between the reciprocal 1 / a of the slope of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.
Therefore, between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, high frequency power is applied to the equal ratio coplanar electrode having a constant equal ratio coplanar electrode constant S / t. The characteristic a of the linear function equation is obtained, and the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the inclination information related to the water repellent layer thickness. The intercept b of b provides an output as initial information related to the moisture content near the surface layer. Thereby, for example, the penetration depth and the like of the silane-based surface impregnated material are measured, and the water-repellent layer thickness of the silane-based surface impregnated material is measured as a regression line.

The horizontal distance t of the equal ratio coplanar electrode constant S / t of the measurement method capable of measuring the thickness of the water repellent layer of the above embodiment is the same as the facing average distance d between the facing electrode plates, Since the horizontal distance t at which the equal ratio coplanar electrode constant S / t satisfies the constant, and the value obtained by multiplying the horizontal distance t by the circling factor π are the same as the facing average distance d between the electrode plates , the electric field is An arc can be drawn, and the facing average distance d between the electrode plates can be calculated as a regression line at the center position of the arc.
Further, since the inclination of the characteristic of the linear function equation of the above embodiment is the inverse 1 / a of the inclination of the characteristic, the inverse 1 / a of the inclination of the characteristic of the linear function equation is a water repellent layer The inclination information is related to the thickness, and the intercept b of the display value Cd depending on the capacitance C is an output as initial information related to the moisture content near the surface layer.

In the measurement method which can measure the thickness of the water repellent layer of the above embodiment, two sheets of the electrode plate area S are paired, and the equal ratio coplanar electrode constant S of the ratio of the horizontal distance t to the center position between the electrode plates High-frequency output is applied to the equal ratio coplanar electrodes on both sides except for the cases where the area ratio of the pair of equal ratio coplanar electrodes is constant and / t is constant, and the horizontal plane to the center position between the electrode plates The characteristic of a linear function equation is obtained between the distance t and the display value Cd depending on the capacitance C, and the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation relates to the water repelling layer thickness An output is obtained as information .
With the exception of the cases where the areas of the pair of equal ratio coplanar electrodes are different from those of the equal ratio coplanar electrodes, the electrode plates of the two equal ratio coplanar electrodes even if they satisfy the equal ratio coplanar electrode constant S / t. It means that the areas S are different from each other.

The invention of the measurement method capable of measuring the thickness of the water repellent layer according to the above embodiment is a ratio of the electrode plate area S to the horizontal distance t to the center position of the electrode plates, using two electrode plate areas S as a pair. The high frequency output is applied to the equal ratio coplanar electrode of which the equal ratio coplanar electrode constant S / t is constant, and the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C Characteristics are obtained, and the gradient a (reciprocal number 1 / a) of the characteristics of the linear function equation is used as the gradient information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is a surface layer The output is obtained as initial information related to the moisture content in the vicinity.
The display value Cd dependent on the capacitance C is specified, and the water repellent layer thickness is calculated from the specified display value Cd.

 Therefore, when the simulated water repellent layer 41 formed with a small amount of application is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the water repellent layer formed with a small amount of application is thin, the slope a is large, and when it is thick, it is small. Therefore, the reciprocal 1 / a of the slope a of the regression line of each sample is the water repellent layer thickness. It can also be expressed. Regarding the relationship between the reciprocal 1 / a of the slope a of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.

Therefore, between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, a high frequency output is applied to the equal ratio coplanar electrode of which the equal ratio coplanar electrode constant S / t is constant. The characteristic of the linear function equation is obtained by the above, and the output is obtained as the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation as inclination information related to the water repellent layer thickness. Thus, for example, the penetration depth and the like of the silane-based surface impregnated material were measured, and in the present embodiment, the water-repellent layer thickness of the silane-based surface impregnated material was measured as a regression line.
In particular, the capacitance C is inversely proportional to the facing average distance d between the electrode plates, ie,
C = ε · S / d
When the region of capacitance C is confirmed as a resistor, the measurement electrode for measuring the difference in moisture content between the inside of the sample and the surface layer portion and the measurement method using the measurement electrode are confirmed. be able to.
The display value Cd depending on the capacitance C may be a capacitance C depending on a frequency, or may be simply a capacitance C depending on a frequency.

In the present embodiment, the case of applying the silane-based surface impregnating material has been described, but in the case of carrying out the present invention, the measurement is based on the premise that the silane-based surface impregnating material is not impregnated with water, It can be generally used without being limited to the silane surface impregnation material.
In addition, when the sample is made to absorb the simulated water repellent layer 41 in concrete and the condition is similar to the two-layer simulated sample model same as the simulated sample, the slope of the regression line is the same as the simulated non-water repellent layer 42 A linear relationship was obtained between the reciprocal of and the water repellent layer thickness.
And, according to the experiments of the inventors, the characteristics of the test specimen as the simulated test specimen in advance are gypsum board, concrete, ALA concrete (artificial lightweight aggregate concrete), ALC, mortar, calcium silicate board, D mode, S mode It had to be used as a property. Moreover, when the water repellent layer thickness was estimated by the manufacturer of the surface impregnating material, it showed close values, but there is a possibility that it may be different. It is thought that further examination is needed by changing the

10 Copper foil tape (electrode)
11 Plastic film 12 Polystyrene foam 14 Wrap film 15, 16 Vinyl-coated copper wire 17, 18 Electrode of high-frequency capacitive moisture meter 20 Equi-planar electrode 21, 22, 21A, 22A Electrode plate 31, 32, 33 Simulated water repellent layer 41 Simulated water-repellent layer 42 Simulated non-water-repellent layer t Horizontal distance d Countering average distance S between opposing electrode plates Electrode plate area C between opposing electrode plates Capacitance ε Dielectric constant S of dielectric between electrodes t equal ratio coplanar electrode constant

The present invention relates to a measurement method for measuring the difference in moisture content between the inside of a sample and the surface layer portion of the thickness of a water repellent layer coated on a concrete surface, and belongs to, for example, the thickness measurement method of water repellent layer is there.

For example, in the case of blending concrete aggregate, it is assumed that the surface is in a “surface dry state (surface dry saturated state)”, the density of the aggregate is determined, and blending is performed according to various blending designs. Here, the "surface dry state" is based on the premise that the internal space of the compacted aggregate is filled with moisture, and the surface of the aggregate is free of moisture. .
Generally, the flow cone method standardized in JIS A1109 is employed to determine the surface dry state of aggregate. According to this, the aggregate is filled into a frustoconical flow cone, and the end is pressed to a predetermined hardness by pushing with a push rod, and then the flow cone is gradually pulled upward and the pressed bone is compacted. The condition near the boundary whether the material collapses or does not collapse is judged as the surface dry condition.

However, these determinations of surface dryness require accurate data in which the aggregate is broken. In particular, heuristics are needed to make accurate decisions. Therefore, an unaccustomed measurer may not be able to make an accurate judgment.
In particular, the flow cone method described above is mainly applied to sand, gravel, etc. called “natural aggregate”, but in recent years, the supply amount of this “natural aggregate” has decreased, and Alternatives are used as aggregate. For example, so-called "low grade" aggregates such as crushed sand, blast furnace slag, refuse melting slag, recycled aggregate and the like are widely used. These low-grade aggregates may exhibit vitreous or porous properties on their surfaces, and may have surface-drying characteristics which are clearly different from those of natural aggregates. Therefore, in the flow cone method, it is particularly difficult to determine an accurate surface dry state for aggregates such as crushed sand.
For example, a method of using a new standard surface dry judgment cone formed by a size such as a self-supporting angle or a wide diameter different from the shape of a flow cone standardized by JIS, the moisture content is measured using infrared reflectance The thing (refer nonpatent literature 1), the thing using change of electric resistance in a wet and dry state (refer nonpatent literature 2), the thing using centrifugal dehydration method (refer nonpatent literature 3), etc. are known.

Takeuchi, Kazuma, 3 others "Basic research on surface dry judgment test method of fine aggregate", Annual Proceedings of Concrete Engineering, Vol. 25, No. 1, 2003, p77-p82 Daisuke Yamamoto, 4 others "Consideration on the method for determining the surface dryness of crushed sand as sand and sand substitute aggregate", 59th Annual Conference of the Japan Society of Civil Engineers, September, 2004, p491-p492 Kazuo Suzuki, 1 other person “A study on simple method for determination of fine aggregate by surface dry”, Proceedings of the 48th Cement Technology Conference, 1994, p156-p159 JP, 2006-329801, A

Non-Patent Document 1 uses flow cones formed by different self-supporting angles and sizes, and a certain degree of empirical rule is required for the determination of the surface dry state as in the prior art, and accurate repeatability is sought. It was difficult. Moreover, it was necessary to select the optimal flow cone suitably according to the kind and property of aggregate, and it was necessary to prepare multiple types of flow cone in advance.
In particular, those utilizing infrared reflectance in Non-Patent Document 1 generally have two types of wavelengths: an infrared wavelength (1.46 μm) that is easily absorbed by water and an infrared wavelength (1.6 μm) that is not easily absorbed by water. Since it was used and was calculated by the data measured mainly for "Shirasu" as aggregate, it was not disclosed about the effect | action with respect to another low grade aggregate.
In Non-Patent Document 2, various measurements are carried out using crushed sand as a sample to be measured, and by combining various results, the result that the flow cone method has the most appropriate result can be obtained, and the other methods are not. The measurement results of Patent Document 2 did not show particularly excellent characteristics.
And in Non-Patent Document 3, although it becomes possible to judge the surface dry state with high accuracy, the target aggregate is set in the centrifugal separator, and the centrifugal force of several G to several G according to the sample In some cases, the apparatus for determining the surface dry state is bulky and is not suitable for simple determination of the surface dry state.

On the other hand, for the improvement of the durability of the present concrete structure, a method of applying a silane-based surface impregnating material to the surface and permeating the surface, and forming a water repellent layer inside the concrete has attracted attention.
By applying the water repellent layer, the penetration of water can be suppressed, and the penetration of deterioration factors of the concrete such as salt and water can be suppressed, whereby the durability of the concrete can be enhanced. For example, “Hokkaido Development Bureau Road Design Guidelines” stipulates that the penetration depth is 6 mm or more in the measures against frost damage as a standard of product selection of silane-based surface impregnation material.
However, in order to confirm the thickness of the applied water repellent layer, there is a method of drilling in concrete and observing. This method of drilling in concrete would damage the construction product and was not necessarily the preferred method. Then, although it is managed by application amount from the relationship between the application amount to the test object produced beforehand, and the water-repellent layer thickness, the construction actual condition is unknown.
The water repellent layer thickness formed by the surface impregnating material is reported to be affected by the moisture content of concrete. The higher the moisture content, the smaller the penetration depth. At the construction site, the moisture content may be different depending on the location due to the influence of rainfall or solar radiation. For this reason, it is also conceivable that the water repellent layer thickness at the site may cause an error from the estimated value by the amount applied to the sample. Moreover, when apply | coating to the existing concrete structure, the test body produced separately does not remain in many cases, and it can not obtain | require the relationship between the application quantity to a test object, and the water-repellent layer thickness.
From such a thing, when applying a surface impregnation method, the quality of construction can be enhanced by managing with the formed water repellent layer. Therefore, the present inventors have investigated a method of estimating the water repellent layer thickness of concrete using electrical changes due to the water content ratio.

 Therefore, the present inventors have provided a method of determining the surface dry state of aggregate with a relatively simple configuration in Patent Document 1 That is, this is mixing and stirring water in the aggregate in the bone-drying state, and mixing and stirring the water in the aggregate in the bone-drying state and the reference sample preparation step of preparing each to a predetermined moisture content respectively The ionized sample preparation step of preparing an ionized substance having conductivity and adding the ionized material having conductivity and stirring the mixture, and a plurality of reference samples having different water contents prepared by the reference sample preparation step and the ionized sample preparation step And filling the plurality of ionized samples having different moisture contents prepared in the above into the measurement container having a predetermined shape and smoothing the sample surface, and the reference sample filled in the measurement container. And a measurement step of measuring a high frequency capacity by bringing a measurement portion of the high frequency capacity moisture meter into contact with the surface of the sample of the ionized sample, and the high frequency capacity moisture meter A reference sample indicating the relationship between the indicated value and the moisture content of the reference sample or the ionized sample, and the addition sample are prepared, and a surface dry point at which the inclination of the addition sample changes with respect to the reference sample It comprises the table dry judging process which specifies and judges the surface dry state.

Thereby, the moisture meter which measures the moisture content of concrete is improved, and the electric field generated from the electrode plate reaches the concrete by changing the distance between the pair of electrode plates by measuring the capacitance. When the electric field is in the water repellent layer, the capacitance decreases at a constant rate, and when the electric field reaches the high water content simulated non-water repellent layer, the rate of decrease in capacitance changes. The inflection point is defined as the boundary between the water repellent layer and the ordinary layer, and a value relatively close to the measured value is obtained.
However, in the water containing concrete of Patent Document 1, pure H ₂ O is a good insulator, and when the pure H ₂ O is measured, the resistance decreases during the measurement. Also, along with that, the dielectric constant also changes depending on the metal ion, and changes as the frequency characteristic of conductivity and dielectric constant depending on the water content. Also, if the measurement target is a large volume, the electric field spreads and the electric field density changes depending on the position of the electrode plate, the area of the electrode plate, and the height of the applied voltage that determines the electric field. Calculation will be needed.

Therefore, the present invention is intended to provide a method for measuring the thickness of a water repellent layer , even if the resistance value and the dielectric constant change depending on the water content without changing the result depending on the water content. It is.

In the method of measuring the thickness of the water repellent layer according to the invention of claim 1, the two electrode plates having the electrode plate area S are paired, and the electrode plate area S and the horizontal distance t to the center position between the electrode plates and each electrode plate It is comprised of an electrode having a isometric coplanar electrode constant S / t in ratio to the area S. A high frequency output is applied to both sides of a pair of equal ratio coplanar electrodes, and the capacitance C is measured. A characteristic of a specific linear function is obtained between a horizontal distance t to the center position of the electrode plates and a display value Cd measured at each electrode depending on the capacitance C, and a slope a of the characteristic of the linear function Is the inclination information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is output as initial information related to the moisture content near the surface layer.

Here, the ratio of the horizontal plane distance t of the test piece to the central position between the electrode plates and the electrode plate area S may be constant. In particular, it is the isometric coplanar electrode constant S / t that satisfies it. (However, even if the geometrical ratio coplanar electrode constant S / t is the same, except for the case where the pair of electrode plate areas are different.)
Further, the horizontal distance t of the above-mentioned equal ratio coplanar electrode constant S / t can be made equal to the facing average distance d between the facing electrode plates on the linear distance. However, it is preferable that the horizontal distance t and the facing average distance d be the same because they are determined by the electrostatic field and the electric field, and they should be offset by a calculation formula.
The slope of the characteristic of the linear function can be the slope of the characteristic or the reciprocal 1 / a of the inclination of the characteristic. In any case, high frequency output is applied to the equal ratio coplanar electrodes on both sides of the equal ratio coplanar electrode, and between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C It is sufficient to draw the characteristics of the linear function.

The invention of the method for measuring the thickness of a water repellent layer according to claim 1 is that the ratio of the electrode plate area S to the horizontal distance t to the center position of the electrode plates is as a pair of two electrode plates having an electrode plate area S. A high frequency output is applied to the equal ratio coplanar electrode of the equal ratio coplanar electrode constant S / t , and the characteristic between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C The slope a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the slope information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is near the surface layer Output as initial information related to the moisture content of

Therefore, when the water repellent layer formed with a small coating amount is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the water repellent layer formed with a small amount of application is thin, the slope a is large, and when it is thick, it decreases. Therefore, the reciprocal 1 / a of the slope of the regression line of each specimen is expressed as the water repellent layer You can also Regarding the relationship between the reciprocal 1 / a of the slope of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.
Therefore, a high frequency output is applied to the equal ratio coplanar electrode of the equal ratio coplanar electrode constant S / t, and a primary value is generated between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C. Taking the characteristic of the functional equation, (reciprocal number 1 / a) of the inclination of the characteristic of the linear functional equation is the inclination information related to the water repellent layer thickness, and the intercept of the display value Cd depending on the capacitance C b obtains an output as initial information related to the moisture content near the surface layer. Thereby, for example, the penetration depth and the like of the silane-based surface impregnated material are measured, and the water-repellent layer thickness of the silane-based surface impregnated material is measured as a regression line.

FIG. 1 is a basic explanatory view illustrating the method of measuring the thickness of the water repellent layer according to the embodiment of the present invention. FIG. 2 is a basic block diagram of the embodiment of the present invention. FIG. 3 is an explanatory view showing the relationship between the water content used in the embodiment of the present invention and the display value in the case where the simulated non-water repellent layer is constant. FIG. 4 is a characteristic diagram showing the relationship between the horizontal distance and the display value according to the simulated specimen used in the embodiment of the present invention. FIG. 5 is an explanatory view showing the relationship between the slope and the intercept of the regression line used in the embodiment of the present invention. FIG. 6 is a characteristic diagram showing the relationship of the intercept at each moisture content used in the embodiment of the present invention. FIG. 7 is a characteristic diagram showing the relationship of the reciprocal of the slope in each moisture content used in the embodiment of the present invention. FIG. 8 is an explanatory view showing the composition of the concrete sample to be measured in the embodiment of the present invention. FIG. 9 is an explanatory view showing the physical properties of the aggregate of the concrete sample to be measured in the embodiment of the present invention. FIG. 10 is a characteristic diagram showing the change of the capacitance of the concrete sample to be measured in the embodiment of the present invention. FIG. 11 is a characteristic diagram showing the reciprocal of the inclination and the water repellent layer thickness measured in the embodiment of the present invention. FIG. 12 is a characteristic diagram of the display value of the test sample of stationary day 1 having the inclined water content distribution measured in the embodiment of the present invention. FIG. 13 is a characteristic diagram of the display value of the specimen of stationary 7 days having the inclined water content distribution measured in the embodiment of the present invention. FIG. 14 is a measurement result diagram showing measured values and estimated values measured in the embodiment of the present invention.

Hereinafter, the method of measuring the thickness of the water repellent layer according to the embodiment of the present invention will be described based on the drawings. Note that, in the embodiment, the same symbols and symbols in the drawings are the same or corresponding functional parts, and therefore the description thereof will not be repeated here.

Embodiment
First, the basic principle of the method of measuring the thickness of the water repellent layer will be described.
In the present invention, a pair of electrodes is a parallel plate, and the configuration of a capacitor in which a dielectric of dielectric constant ε is sandwiched therebetween is used. The electrode plate area S of the parallel electrode plates is in the state of being disposed apart by the facing average distance d between the electrode plates opposite to each other in parallel. The capacitance C of the electrode plate of the electrode plate area S at this time is proportional to the dielectric constant ε of the dielectric between the electrode plate area S and the electrode plate, and the capacitance C of the electrode plate is S The capacitance C is expressed by the following equation.
C = ε · S / d
Where C (F) capacitance
S (m ² ) Electrode plate area between facing electrode plates
d (m) opposing average distance between opposing electrode plates
ε (F / m) is the dielectric constant of the dielectric between the electrode plates.

As the high frequency source, since the inventors are used to handling, a commercially available high-frequency capacitive moisture meter (HI-520: manufactured by Ketto Scientific Research Institute, Inc., high-frequency capacitive type (20 MHz)) electrodes 17 and 18 The high frequency output from was used.
In the experiments of the inventors, a high-frequency capacitive moisture meter is used instead of the LCR meter, but as a result, the value of the capacitance C is not measured, but the output is relayed. The capacitance C of the test material (aggregate) is not calculated based on the dielectric constant ε at a high frequency (20 MHz).
If a general LCR meter is used, it is necessary to consider the influence of stray capacitances of the electrodes 17, 18, etc. As a result, it is considered that a commercially available high frequency capacitive moisture meter is more useful.

First, when water is included in the aggregate of the test material, a phenomenon occurs in which the capacitance C increases with the increase of water. Usually, when the capacitance C is calculated from the dielectric loss tangent tan δ,
It is expressed by the current Ir of the resistance component / the current Ic of the capacitor capacitance component, and the equation is
tan δ = Ir / Ic
It becomes.
However, the dielectric constant of about 80 of water changes with the change of temperature and also changes with the frequency applied, and a chemical reaction occurs and also changes with the application time and the like. This is largely due to the action of melting by ions and the like.
Moreover, although the electrostatic capacitance C is calculated as C = (epsilon) * S / d, the area | region pinched | interposed between electrodes can also be caught as a resistor.
Therefore, as the phenomenon, when the aggregate of the test material is made to contain water, the capacitance C increases with the increase of water, so it was decided to capture only that event.
The amount of increase in capacitance C as the water content increases is converted in accordance with a conversion formula previously obtained using mortar, concrete, and various other test materials, and is displayed as the water content. Here, in the test material having no conversion formula, the mode is switched to the direct mode (D mode) of a commercially available high-frequency capacitive moisture meter, and a numerical value correlated with the capacitance C is displayed as a display value Cd. As a precaution, the display value of the direct mode used by the inventors is displayed between "0 and 2999".

 A high frequency output (AC voltage) was applied to both electrode plates, and a band-like electric field was generated therebetween, and the capacitance C of the test material on this electric field was measured. The shape of the electric field is considered to be arc-like or elliptical depending on the boundary conditions etc. However, "It is possible to evaluate the amount of dielectric physical properties to a depth proportional to the electrode spacing (S. Tetsuro:" by dielectric measurement with surface depth resolution Since it is said that “Development diagnosis technology for polymer electrical insulation materials” (FY 2004-2006 Grant-in-Aid for Scientific Research Grants), the opposing distance d between the electrode plates and the depth of the electric field It was assumed that it was a circular arc shape that was simply proportional. The electrode plates were arranged in parallel so that the electric field was transmitted through the test material, and it was assumed that the depth at which the electric field reached would be changed by changing the facing average distance d between the electrode plates.

 Further, the dielectric constant ε of the dielectric changes in accordance with the water content. Further, the facing average distance d between the electrode plates is the facing average distance length of the arc-like electric field. When the facing average distance d between the electrode plates is small, the electric field exists only in the simulated water repellent layer 41, and the capacitance C decreases with the increase in the facing average distance d between the electrode plates. When the electric field reaches the simulated non-water repellent layer 42 having a high water content, the dielectric constant ε also changes, and the reduction rate of the display value Cd changes.

 Therefore, logically, this inflection point is the boundary between the simulated water repellent layer 41 and the simulated non-water repellent layer 42. The estimated value of the water repellent layer thickness at this time was close to the confirmed value confirmed by the measurement. However, if the simulated water repellent layer 41 is thin, an inflection point appears immediately, which makes it difficult to determine the inflection point. In addition, when the width of the electrode plate is narrowed for thin water-repellent layer thickness measurement, there is a disadvantage that the accuracy is lowered. That is, it is estimated that the electric field affects the side of the non-water repellent layer 42 from the beginning.

Next, the electrode plates 21, 22, 21A, 22A shown in FIG. 1 used in the embodiment of the present invention will be examined.
An electrode was manufactured such that the ratio S / t of the horizontal plate distance t from the center position of one electrode plate to the center position of the other electrode plate and the electrode plate area S was constant. An electrode in which the ratio S / t of the horizontal plane distance t to the electrode plate area S is constant is referred to as a "equal ratio coplanar electrode". Further, although the horizontal distance t is defined for the electrode plates 21, 22, 21A, 22A, it may be a vertical surface or may have a predetermined inclination. Here, in order to clarify the difference with the facing average distance d between electrode plates, it is called horizontal surface distance t. Here, S / t = const is referred to as "equal ratio coplanar electrode constant".

Here, a value obtained by multiplying the horizontal distance t by the circle ratio π is set as the facing average distance d between the electrode plates.
π · t = d
t = d / π
It becomes.
Therefore,
S / t = S · π / d
It becomes. The circle ratio π is constant, and the uniform coplanar electrode constant S / d is always constant.
In addition, the capacitance C is constant, if the dielectric constant ε, that is, the water content does not change in the depth direction, according to C = ε · S / d.
Then, when the horizontal distance t is sequentially increased, when the electric field reaches a portion with high water content, the capacitance C changes for the first time, and the value of the changed position becomes the depth of the simulated water repellent layer 41 .

The inventors further investigate iso-coplanar electrodes 21, 22, 21A and 22A (hereinafter, these will be collectively referred to as “e-coplanar electrode 20”).
Five types of equal ratio coplanar electrodes 20 having horizontal surface distances t of 4, 8, 12, 16, and 20 mm were produced. The electrode plate length of the equal ratio coplanar electrode 20 was constant at 100 mm, and the electrode plate width was changed to set the equal ratio coplanar electrode constant S / t = 100. In this case, since the width of the electrode plate offsets the horizontal distance t, the facing average distance d between the electrode plates and the horizontal distance t of the equal ratio coplanar electrode 20 are the same (the facing average distance d between the electrode plates d = horizontal distance t) And Here, electrode plates having different areas of the pair of equal ratio coplanar electrodes 20 were excluded.

As a material of an electrode plate, as shown in FIG. 2, the copper foil tape 10 was stuck on the plastic film 11, and also the plastic film 11 was stuck on the polystyrene foam 12 of 25 mm. Vinyl coated copper wires 15 and 16 were attached to the copper foil tape 10 as an electrode plate and extended, and brought into contact with the electrodes 17 and 18 of a commercially available high-frequency capacitive moisture meter. Although the lengths of the vinyl-coated copper wires 15 and 16 as lead wires are different in FIG. 2, they are uniform in length in the test circuit. The circuit has symmetry and is drawn out on the opposite side.
In particular, when both vinyl coated copper wires 15 and 16 are brought close to each other, they are influenced by the electrostatic stray capacitance and affect the displayed value Cd of the output, so they are separated from each other so that the influence becomes the minimum value. In order to electrically connect only the upper surface of the electrode 21A (21) and the electrode 22A (22) to the upper surface of the simulated sample, a wrap film 14 is applied to electrically insulate the other upper surface of the simulated sample.
Also, a 2 kg weight 13 was placed on the polystyrene foam 12 in order to bring the copper foil tape 10 into close contact with the test piece.

Using the equal ratio coplanar electrode 20 manufactured in this manner, a simulated specimen with a constant water content was manufactured, and the characteristics of the display value Cd of the carbon plate and the concrete were measured. A caikale plate is easily processed at a thickness of 5 mm, has a high water absorption rate, and has a high water absorption rate, and was adopted as a simulated specimen.
A sample of 5 mm in thickness x 100 mm in length x 100 mm in width is subjected to oven drying at 105 ° C. for 24 hours to obtain a water content of 0%. The sample was placed in a plastic bag with water of such a mass as to cause water absorption, and was then absorbed to make a sealed test sample. Then, as shown in FIG. 3, a caical plate having a moisture content of 0, 6, 12% when the whole of the simulated specimen was 100% was manufactured. In addition, concrete manufactured cubes with a moisture content of 0, 4 and 6.4%.

Here, since the bone dry plate has an absolute dry density of about 0.7 g / cm ³ , which is about 1/3 of that of concrete, the amount of water containing water is about 1⁄3 of that of concrete with the same water content. Eight equal carbon content plates having the same water content were stacked to prepare an equal ratio coplanar electrode 20, and the value of the display value Cd was measured.
The concrete was prepared by cutting a 100 × 100 × 400 mm concrete simulation specimen prepared with a 55% water / cement ratio into cubes of 100 mm square and saturated with water to obtain a surface dry state (water content: 6.4%) What was adjusted so that the moisture content and the moisture content of the same dimensions as that of the one were adjusted to 4.0% and 0% was put in a plastic bag and sealed, and water was uniformly adsorbed to obtain a simulated specimen of a predetermined moisture content.
Here, the relationship between the horizontal distance t of the simulated specimen and the display value Cd is shown in FIG.

As shown in FIG. 3, it can be seen that the display value Cd is substantially constant even if the horizontal surface distance t is changed, if the water content of the concrete and the carbon plate is constant. Once the indicated value Cd and the specimen such as concrete or caulcal plate are known, the moisture content of the specimen is specified. Here, it is presumed that the error of the indicated value Cd is due to the difference in the characteristic of the moisture content distribution to the caulcal board and the general relation of the concrete, and the difference in the moisture content depending on the individual.
In addition, even if the horizontal distance t to the electrode plate center position at each moisture content increases, it is confirmed that the value of the display value Cd does not change and becomes substantially constant even if the horizontal distance t decreases.
Then, if the equi-coplanar electrode constant S / t is constant, the dielectric constant ε (water content) changes even if the horizontal distance t to the electrode center position is increased and the position where the electric field reaches is deepened. If not, the display value Cd is the same value. Then, the result was obtained that the value of the display value Cd becomes larger as the moisture content becomes higher. From this, it can be seen that the indicated value Cd depends on the water content.

Next, measurement of the simulated specimen of the simulated water repellent layer 41 is performed using this equal ratio coplanar electrode 20.
1 or 2 or 3 sheets of 0, 6 and 12% silicon plates are placed on the concrete cubes with water content of 6.4% and 4.0% shown in FIG. 2 and FIG. 3, and lamination of each electrode plate The display value Cd was measured in the state. The carbon plate is a two-layer simulated specimen model in which the simulated water repellent layer 41 having a low water content is simulated, and the concrete non-water repellent layer 42 having a high water content is simulated.

As shown in FIG. 4, one, two, three, or four pieces of silicon boards with a moisture content of 0% are stacked on concrete having a dielectric constant ε and a moisture content of 6.4%, and the horizontal distance t to the electrode plate center position and each display The relationship of the value Cd is illustrated.
As shown in FIG. 4, the inclination of the straight line is large when the thickness of 5 mm of the silicon plate is as thin as one, and the inclination is small when the thickness of three laminated sheets is 15 mm.
Further, the intersection point of the y-axis intersecting the y-axis at x = 0 which does not depend on the thickness of the caiscal plate, that is, the intercept b of the display value Cd is substantially the same value. The value showed a value close to the indicated value Cd = 1270 in the case of overlapping the silica plates having a water content of 0% shown in FIG. A linear relationship, ie, a linear function equation of the display value Cd, is also used in the case of using a calcium carbonate of other moisture content
Display value Cd = ax + b = ax + 1270
The display value Cd is the vertical axis (y), and x is the horizontal axis.
was gotten. The intercept b of the indicated value Cd is shown in FIG.
The slope of each straight line obtained by linear regression of the relationship between the display value Cd and the horizontal distance t obtained by changing the moisture content of concrete and caycal board and the number of stacked caical boards and changing it. An intersection point of a and x = 0 y axis (display value Cd) is a display value Cd.

The larger the difference between the moisture content of the cical plate regarded as the simulated water repellent layer 41 and the moisture content of concrete regarded as the simulated non-water repellent layer 42, the larger the inclination of the regression line. It is considered that if the impedance of the capacitance Ca of the caical plate and the impedance of the capacitance Cb of concrete are considered to be connected in series, when Ca 接 続 Cb by the comparison of impedances, the capacitors are connected in series The amount of work is dependent on Ca, which has a large capacitance impedance.
In particular, when the moisture content of concrete is 4% and the moisture content of the cical plate placed above is 12%, the difference between the moisture content of the two is not so large, the inclination becomes negative when the number of cical plates is increased. , The correlation coefficient of the regression line also decreases.
In addition, when the thickness of the simulated water repellent layer 41 was large, that is, as the number of the silica plates was increased, the inclination was reduced. In the case where the moisture content of the caycal plate is the same, as shown by the relationship between the moisture content and the segment shown in FIG. 6, the values of the segment b become substantially the same even if the number of overlapping sheets is changed. In particular, since the water content is constant and there is no change in the water content, it is estimated that the same can be obtained regardless of how many sheets are used.
Also, it is considered that the simulated water repellent layer 41 is a desirable measurement method because the moisture content is very small.

In addition, in the case of three caical plates (15 mm thick), the display value Cd does not change with electrodes having a horizontal distance t of 4 mm and 8 mm, so the electric field has a large effect on the simulated non-water repellent layer 42 with high moisture content It is presumed that there is no
Although it was estimated that the display value Cd would increase rapidly at 12 mm and 16 mm or more starting to reach the simulated non-water repellent layer 42, the display value Cd would increase continuously and a linear relationship was obtained between the horizontal distance t and the display value Cd. No continuous points occurred. The electric field shape is also presumed to be an arc when the electrode plates face each other in the opposite state, but the electric field in the sample is the same as the sum of the capacitances as impedances connected in series between equal ratio coplanar electrodes 20. Detailed analysis, such as investigation of the influence of the difference in the shape of the water content and the moisture content, will be the subject for future study.

The moisture content of the caking plate piled up at 6% and 4% of the concrete content, the reciprocal of the slope 1 / a of the regression line obtained by changing the thickness of the caking plate with 0% and 12%, respectively The relationship with the thickness of the caycal plate is shown in FIG. The linear relationship which can be shown by a linear function equation was obtained for the reciprocal 1 / a of the slope and the thickness of the caycal plate, respectively.
From this, if the relationship between the reciprocal 1 / a of the slope and the thickness of the water repellent layer is determined in advance for each sample, the regression line of the horizontal distance t and the display value Cd obtained by measuring with the equal ratio coplanar electrode 20 The water repellent layer thickness can be estimated from the slope a or the reciprocal 1 / a of the slope.

Next, it examines using the example of these obtained simulated specimens.
First, a concrete simulation sample on which a simulation water repellent layer 41 was formed was measured with a uniform ratio coplanar electrode 20, and the reciprocal 1 / a of the slope of the regression line as obtained for the simulation sample and the water repelling layer thickness Examine the relationship.
The concrete used three types of compounding. The composition of the concrete and the 28-day compressive strength are shown in FIG.
The water to cement ratio (referred to as W / C in FIG. 8) was 40, 55, 70%. Relatively low quality such as ordinary concrete with 55% water / cement ratio and 5% air content, which are used in general structures, and 40% water / cement ratio assuming relatively high strength The amount of air can be reduced without using an AE agent (a type of surfactant, an additive that improves the efficiency of concrete placement and the freeze resistance) at a low water-cement ratio of 70% assuming concrete. It was decided to be. The cement used was early-strength cement.
The physical properties of the used aggregate are shown in FIG. The coarse aggregate used grated stone from Nagara River, and the fine aggregate was a mixture of coarse sand and fine sand from Nagara River at a ratio of 7: 3.
Here, s / a is a fine aggregate rate (the ratio of the volume of the fine aggregate to the volume of the total aggregate), and in this case, s / a = 40%. Moreover, S1 is a coarse thing among fine aggregates, S2 is a fine thing among fine aggregates, G is a coarse aggregate.

As shown in FIG. 8, two types of curing were used: curing in water and curing in air for 28 days after demolding.
A specimen of a square column of 100 mm × 100 mm × 400 mm was prepared, and after curing, it was cut using a concrete cutter to make 50 mm × 100 mm × 130 mm. After making a bank on a 100 mm × 130 mm cut surface so that the surface impregnating material does not drip on the side surface of the sample, it was dried in an oven to be completely dried, and further, the surface impregnating material was applied.
The surface impregnating material is manufactured by TOOKEN CHEMICAL CO., LTD. (Product name S-7; hereinafter simply referred to as "made by T company") and Daido Paint Co., Ltd. (product name aqua seal 1400; hereinafter referred to simply as "made by company D") Was used. The product of company T is liquid, and the product of company D is gel.
Both of the components were silanes, and the standard amount used was 200 g / m ² . The coating amount was set to ^{100g / m 2 ~500g / m 2} , a portion of the specimen number was applied 50 and 800 g / m ^2. The number of specimens was 68 in all.

After leaving for 4 days or more after application so as to form the simulated water repellent layer 41, the sample was placed in a container and immersed in water. The depth of water was set to the height of the specimen, and water was allowed to absorb from the bottom and the side of the specimen for 4 days. The simulated water repellent layer 41 has a very low water absorption rate, and the simulated non-water repellent layer 42 has a high water absorption rate, so the simulated water repellent layer 41 has a small water content like the simulated sample and the simulated non water repellent layer has a high water content. Forty-two two-layer specimen models were constructed.
Fig. 10 shows that 100, 300, 500 g / m ² of surface impregnated material from T Co. is applied to those cured in water at a cement ratio of 55% with water, but the horizontal distance t to the electrode plate center position and the indicated value Cd Show the relationship between It shows that a linear relationship (linear characteristic) can be obtained in the display value Cd depending on the horizontal distance t to the electrode plate center position and the capacitance C as in the case of the simulated specimen.
After the measurement, each sample was split and the actually formed water repellent layer thickness was measured. The measurement averaged the value in the center part and the part of the position of 25 mm on both sides. When the simulated water repellent layer 41 formed with a small coating amount is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b has substantially the same value, and the water content of the water repellent layer portion is considered to be the same.
The coating amount of the surface impregnating material is 100, 300 and 500 g / m ² , but the inclination a is large when the water repellent layer formed with a small coating amount is thin, and is small when it is thick.
In this way, the slope a is obtained as a linear function of the relationship between the display value Cd measured by the electrode shown in FIG. 10 and the distance t to the center of the electrode. As in the case of 4.8 mm, 10.2 mm and 14.0 mm in FIG. 10, the sample is divided to obtain the actual water repellent layer thickness.

Furthermore, FIG. 11 shows the relationship between the reciprocal 1 / a of the slope of the regression line of each simulated specimen and the measured value of the water repellent layer thickness.
The Y axis in Figure 11 uses the water repellent layer thickness actually measured by dividing the sample, and the X axis uses the reciprocal 1 / a of the slope a to obtain a linear function.
As a formula,
The water repellent layer thickness is 164.5 × (1 / a) + 1.302.
If the sample whose water repellent layer is unknown is measured with an electrode and the inclination a is obtained, the water repellent layer can be determined from this equation.
In FIG. 11, the number of test specimens is 68, which is the sum of simulated test specimens coated with T company and D company. The reciprocal 1 / a of the slope is confirmed from the water repellent layer thickness X measured by making the reciprocal 1 / a of the slope of each simulated specimen and the intercept b of the measured value of the water repellent layer common to the indicated value Cd. Be done.
Therefore, the reciprocal 1 / a of the slope is determined from the straight line of the linear function equation expressed by the 68 data, and if the reciprocal 1 / a of the slope is identified, the water repellent layer thickness is identified.
A linear relationship was obtained for the reciprocal of the slope and the water repellent layer thickness as in the case of the simulated specimen. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.

Next, a method of measuring the thickness of the water repellent layer assuming an actual structure will be described.
In the sample described above, the simulated water repellent layer 41 has a low moisture content, and the simulated non-water repellent layer 42 has a two-layer sample model with a high moisture content close to the surface dry state.
However, in an actual structure, the water content is not a two-layer sample model, but is estimated to be a slope distribution in which the vicinity of the surface is low and the height gradually increases toward the center. Assuming a slope distribution, the prismatic specimen cured in water at a cement ratio of 55% with water is divided into two equal parts, and those sealed with a rubber-based paint to prevent entry and exit of water except for the cut surface are immersed for 3 days, It stood still in the laboratory for 7 days and 1 day. Two of them were allowed to stand.
The seven-day Gifu Meteorological Observatory records that this test was conducted showed an average temperature of 6.3 ° C and an average humidity of 62%. After standing, 200 g / m ^{2 of a} surface impregnating material manufactured by D was applied to the cut surface. The indicated value Cd was measured with the electrode before application and 4 days after application.
After the measurement, it was split to measure the simulated aqueous layer depth. The relationship between the horizontal distance t to the electrode center before application and after application and the display value Cd is illustrated.

As for what was dried for 1 day, as shown in FIG. 12, the display value Cd before application becomes a value close to the display value Cd = 1900 of the surface dry state (water content 5.2%) even when the horizontal distance t is 4 mm. Most of the water is not evaporated, and it is presumed to be in a saturated state. Although the indicated value Cd decreased even after the application, it was an almost constant value and a clear slope was not obtained, and the water repellent layer thickness could not be estimated.
The estimation of the water repellent layer thickness in a moisture content distribution with a slope assuming an actual structure may have few experimental examples and may need to be corrected in the future. In the future, it is necessary to further study, such as changing the moisture content.

In addition, as shown in FIG. 13, the display value Cd before application is as low as 1900 at a horizontal distance t of 4 mm, the display value Cd is as low as 1900, and is substantially the same for 8 mm or more. It has become. The indicated value Cd at 8 mm or more is a value close to the indicated value of the concrete in the surface dry state (water content: 6.4%) shown in FIG. 3, and it is considered that the inside is saturated.
After application, the display value Cd decreased at 4, 8 and 12 mm, and became a value close to the value before application at 16 mm or more. Linear regression was performed using the value up to 16 mm at which the increase in the display value Cd after application almost disappeared, and the slope a was determined. An estimated value and an actual measurement value obtained by estimating the water repellent layer thickness from the relationship between the inverse 1 / a of the slope and the water repellent layer thickness using the slope a are shown in FIG. The estimated value and the measured value show relatively close values.

In the method of measuring the thickness of the water repellent layer according to the above-mentioned embodiment, two sheets of the same electrode plate area S are paired, and the ratio of the horizontal distance t to the center position between the electrode plates is equal ratio coplanar electrode constant S / t A high frequency is applied to the equal ratio coplanar electrode 20 and the equal ratio coplanar electrode 20 on both sides, and the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C based on the high frequency The linear function equation Y = aX + Cd characteristic is obtained between them, and the output is obtained as the inclination a or the inverse 1 / a of the characteristic of the linear function as inclination information related to the water repellent layer thickness.
Here, by measuring gypsum board, concrete, ALA concrete (artificial lightweight aggregate concrete), ALC, mortar, calcium silicate board, D mode, S mode characteristics, as initial information related to the moisture content near the surface layer An intercept b of the display value Cd is calculated.
Further, if the reciprocal 1 / a of the slope in the characteristic of the linear function equation is the inclination information related to the water repellent layer thickness, and if the reciprocal 1 / a of the inclination of the characteristic of the known linear function equation is set as a standard In addition, if the point at which the display value Cd dependent on the capacitance C matches is determined, the water repellent layer thickness can be calculated.

In the method of measuring the thickness of the water repellent layer according to the above embodiment, two sheets of the electrode plate area S are a pair, and the ratio of the ratio of the horizontal plate distance S to the electrode plate area S to the center position between the electrode plates is equal ratio A characteristic between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, for example, adding a high frequency output of 20 MHz to the equal ratio coplanar electrode of the plane electrode constant S / t. The slope a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the slope information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is near the surface layer The output is obtained as the initial information related to the moisture content of
At this time, the 20 MHz of the high frequency is not limited to the 20 MHz, and may be an alternating current. However, if the frequency is low, a chemical reaction such as electrolysis of water occurs, and if the frequency is high, a magnetic field can not be generated inside the dielectric, and the magnetic field on the outer surface becomes high.
Also, although the characteristics of the linear functional equation are preferably linear, they can not be used non-linearly. Therefore, when the simulated water repellent layer 41 formed with a small coating amount is thin, the inclination a may be large, and when it is thick, the inclination a may be small.

Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the simulated water repellent layer 41 formed with a small amount of application is thin, the slope a is large, and when it is thick, it decreases. Therefore, the reciprocal 1 / a of the slope of the regression line of each sample is It can also be expressed as Regarding the relationship between the reciprocal 1 / a of the slope of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.
Therefore, between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, high frequency power is applied to the equal ratio coplanar electrode having a constant equal ratio coplanar electrode constant S / t. The characteristic a of the linear function equation is obtained, and the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the inclination information related to the water repellent layer thickness. The intercept b of b provides an output as initial information related to the moisture content near the surface layer. Thereby, for example, the penetration depth and the like of the silane-based surface impregnated material are measured, and the water-repellent layer thickness of the silane-based surface impregnated material is measured as a regression line.

Horizontal distance t geometric coplanar electrodes constant S / t of the thickness measuring method of the water-repellent layer of the above-described embodiment, since those were the same as opposed average distance d of the opposing electrode plates, geometric co Since the horizontal distance t satisfying the surface electrode constant S / t and the value obtained by multiplying the horizontal distance t by the circular ratio π are the same as the opposing average distance d between the electrode plates, the electric field draws an arc. The opposing average distance d between the electrode plates can be calculated as a regression line at the center position of the arc.
Further, since the inclination of the characteristic of the linear function equation of the above embodiment is the inverse 1 / a of the inclination of the characteristic, the inverse 1 / a of the inclination of the characteristic of the linear function equation is a water repellent layer The inclination information is related to the thickness, and the intercept b of the display value Cd depending on the capacitance C is an output as initial information related to the moisture content near the surface layer.

In the method of measuring the thickness of the water repellent layer according to the above embodiment, two sheets of the electrode plate area S are paired, and the ratio of the horizontal distance t to the center position between the electrode plates is equal ratio coplanar electrode constant S / t. A high frequency output is applied to the equal ratio coplanar electrodes and the equal ratio coplanar electrodes on both sides except that the area of a pair of equal ratio coplanar electrodes is different, and the horizontal distance t to the center position between the electrode plates Obtain a characteristic of a linear function equation with a display value Cd depending on the capacitance C, and output the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation as the inclination information related to the water repellent layer thickness To get
With the exception of the cases where the areas of the pair of equal ratio coplanar electrodes are different from those of the equal ratio coplanar electrodes, the electrode plates of the two equal ratio coplanar electrodes even if they satisfy the equal ratio coplanar electrode constant S / t. It means that the areas S are different from each other.

The invention of the method of measuring the thickness of the water repellent layer according to the above embodiment is characterized in that the two electrode plate areas S are paired and the ratio of the ratio of the electrode plate area S to the horizontal distance t to the center position of the electrode plates is equal. By applying a high frequency output to the equal ratio coplanar electrode of the coplanar electrode constant S / t, and obtaining the characteristic between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, The slope a (reciprocal number 1 / a) of the characteristic of the linear function equation is the slope information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is the moisture content near the surface layer Get the output as the relevant initial information.
The display value Cd dependent on the capacitance C is specified, and the water repellent layer thickness is calculated from the specified display value Cd.

 Therefore, when the simulated water repellent layer 41 formed with a small amount of application is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the water repellent layer formed with a small amount of application is thin, the slope a is large, and when it is thick, it is small. Therefore, the reciprocal 1 / a of the slope a of the regression line of each sample is the water repellent layer thickness. It can also be expressed. Regarding the relationship between the reciprocal 1 / a of the slope a of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.

Therefore, a high frequency output is applied to the equal ratio coplanar electrode of the equal ratio coplanar electrode constant S / t, and a primary value is generated between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C. The characteristic of the functional equation is obtained, and an output is obtained as the inclination a (reciprocal number 1 / a) of the characteristic of the linear functional equation as inclination information related to the water repellent layer thickness. Thus, for example, the penetration depth and the like of the silane-based surface impregnated material were measured, and in the present embodiment, the water-repellent layer thickness of the silane-based surface impregnated material was measured as a regression line.
In particular, the capacitance C is inversely proportional to the facing average distance d between the electrode plates, ie,
C = ε · S / d
When the region of capacitance C is confirmed as a resistor, the measurement electrode for measuring the difference in moisture content between the inside of the sample and the surface layer portion and the measurement method using the measurement electrode are confirmed. be able to.
The display value Cd depending on the capacitance C may be a capacitance C depending on a frequency, or may be simply a capacitance C depending on a frequency.

In the present embodiment, the case of applying the silane-based surface impregnating material has been described, but in the case of carrying out the present invention, the measurement is based on the premise that the silane-based surface impregnating material is not impregnated with water, It can be generally used without being limited to the silane surface impregnation material.
In addition, when the sample is made to absorb the simulated water repellent layer 41 in concrete and the condition is similar to the two-layer simulated sample model same as the simulated sample, the slope of the regression line is the same as the simulated non-water repellent layer 42 A linear relationship was obtained between the reciprocal of and the water repellent layer thickness.
And, according to the experiments of the inventors, the characteristics of the test specimen as the simulated test specimen in advance are gypsum board, concrete, ALA concrete (artificial lightweight aggregate concrete), ALC, mortar, calcium silicate board, D mode, S mode It had to be used as a property. Moreover, when the water repellent layer thickness was estimated by the manufacturer of the surface impregnating material, it showed close values, but there is a possibility that it may be different. It is thought that further examination is needed by changing the

10 Copper foil tape (electrode)
11 Plastic film 12 Polystyrene foam 14 Wrap film 15, 16 Vinyl-coated copper wire 17, 18 Electrode of high-frequency capacitive moisture meter 20 Equi-planar electrode 21, 22, 21A, 22A Electrode plate 31, 32, 33 Simulated water repellent layer 41 Simulated water-repellent layer 42 Simulated non-water-repellent layer t Horizontal distance d Countering average distance S between opposing electrode plates Electrode plate area C between opposing electrode plates Capacitance ε Dielectric constant S of dielectric between electrodes t equal ratio coplanar electrode constant

The present invention relates to a measurement method for measuring the difference in moisture content between the inside of a sample and the surface layer portion of the thickness of a water repellent layer coated on a concrete surface, and belongs to, for example, the thickness measurement method of water repellent layer is there.

For example, in the case of blending concrete aggregate, it is assumed that the surface is in a “surface dry state (surface dry saturated state)”, the density of the aggregate is determined, and blending is performed according to various blending designs. Here, the "surface dry state" is based on the premise that the internal space of the compacted aggregate is filled with moisture, and the surface of the aggregate is free of moisture. .
Generally, the flow cone method standardized in JIS A1109 is employed to determine the surface dry state of aggregate. According to this, the aggregate is filled into a frustoconical flow cone, and the end is pressed to a predetermined hardness by pushing with a push rod, and then the flow cone is gradually pulled upward and the pressed bone is compacted. The condition near the boundary whether the material collapses or does not collapse is judged as the surface dry condition.

However, these determinations of surface dryness require accurate data in which the aggregate is broken. In particular, heuristics are needed to make accurate decisions. Therefore, an unaccustomed measurer may not be able to make an accurate judgment.
In particular, the flow cone method described above is mainly applied to sand, gravel, etc. called “natural aggregate”, but in recent years, the supply amount of this “natural aggregate” has decreased, and Alternatives are used as aggregate. For example, so-called "low grade" aggregates such as crushed sand, blast furnace slag, refuse melting slag, recycled aggregate and the like are widely used. These low-grade aggregates may exhibit vitreous or porous properties on their surfaces, and may have surface-drying characteristics which are clearly different from those of natural aggregates. Therefore, in the flow cone method, it is particularly difficult to determine an accurate surface dry state for aggregates such as crushed sand.
For example, a method of using a new standard surface dry judgment cone formed by a size such as a self-supporting angle or a wide diameter different from the shape of a flow cone standardized by JIS, the moisture content is measured using infrared reflectance The thing (refer nonpatent literature 1), the thing using change of electric resistance in a wet and dry state (refer nonpatent literature 2), the thing using centrifugal dehydration method (refer nonpatent literature 3), etc. are known.

Takeuchi, Kazuma, 3 others "Basic research on surface dry judgment test method of fine aggregate", Annual Proceedings of Concrete Engineering, Vol. 25, No. 1, 2003, p77-p82 Daisuke Yamamoto, 4 others "Consideration on the method for determining the surface dryness of crushed sand as sand and sand substitute aggregate", 59th Annual Conference of the Japan Society of Civil Engineers, September, 2004, p491-p492 Kazuo Suzuki, 1 other person “A study on simple method for determination of fine aggregate by surface dry”, Proceedings of the 48th Cement Technology Conference, 1994, p156-p159 JP, 2006-329801, A

Non-Patent Document 1 uses flow cones formed by different self-supporting angles and sizes, and a certain degree of empirical rule is required for the determination of the surface dry state as in the prior art, and accurate repeatability is sought. It was difficult. Moreover, it was necessary to select the optimal flow cone suitably according to the kind and property of aggregate, and it was necessary to prepare multiple types of flow cone in advance.
In particular, those utilizing infrared reflectance in Non-Patent Document 1 generally have two types of wavelengths: an infrared wavelength (1.46 μm) that is easily absorbed by water and an infrared wavelength (1.6 μm) that is not easily absorbed by water. Since it was used and was calculated by the data measured mainly for "Shirasu" as aggregate, it was not disclosed about the effect | action with respect to another low grade aggregate.
In Non-Patent Document 2, various measurements are carried out using crushed sand as a sample to be measured, and by combining various results, the result that the flow cone method has the most appropriate result can be obtained, and the other methods are not. The measurement results of Patent Document 2 did not show particularly excellent characteristics.
And in Non-Patent Document 3, although it becomes possible to judge the surface dry state with high accuracy, the target aggregate is set in the centrifugal separator, and the centrifugal force of several G to several G according to the sample In some cases, the apparatus for determining the surface dry state is bulky and is not suitable for simple determination of the surface dry state.

On the other hand, for the improvement of the durability of the present concrete structure, a method of applying a silane-based surface impregnating material to the surface and permeating the surface, and forming a water repellent layer inside the concrete has attracted attention.
By applying the water repellent layer, the penetration of water can be suppressed, and the penetration of deterioration factors of the concrete such as salt and water can be suppressed, whereby the durability of the concrete can be enhanced. For example, “Hokkaido Development Bureau Road Design Guidelines” stipulates that the penetration depth is 6 mm or more in the measures against frost damage as a standard of product selection of silane-based surface impregnation material.
However, in order to confirm the thickness of the applied water repellent layer, there is a method of drilling in concrete and observing. This method of drilling in concrete would damage the construction product and was not necessarily the preferred method. Then, although it is managed by application amount from the relationship between the application amount to the test object produced beforehand, and the water-repellent layer thickness, the construction actual condition is unknown.
The water repellent layer thickness formed by the surface impregnating material is reported to be affected by the moisture content of concrete. The higher the moisture content, the smaller the penetration depth. At the construction site, the moisture content may be different depending on the location due to the influence of rainfall or solar radiation. For this reason, it is also conceivable that the water repellent layer thickness at the site may cause an error from the estimated value by the amount applied to the sample. Moreover, when apply | coating to the existing concrete structure, the test body produced separately does not remain in many cases, and it can not obtain | require the relationship between the application quantity to a test object, and the water-repellent layer thickness.
From such a thing, when applying a surface impregnation method, the quality of construction can be enhanced by managing with the formed water repellent layer. Therefore, the present inventors have investigated a method of estimating the water repellent layer thickness of concrete using electrical changes due to the water content ratio.

  Therefore, the present inventors have provided a method of determining the surface dry state of aggregate with a relatively simple configuration in Patent Document 1 That is, this is mixing and stirring water in the aggregate in the bone-drying state, and mixing and stirring the water in the aggregate in the bone-drying state and the reference sample preparation step of preparing each to a predetermined moisture content respectively The ionized sample preparation step of preparing an ionized substance having conductivity and adding the ionized material having conductivity and stirring the mixture, and a plurality of reference samples having different water contents prepared by the reference sample preparation step and the ionized sample preparation step And filling the plurality of ionized samples having different moisture contents prepared in the above into the measurement container having a predetermined shape and smoothing the sample surface, and the reference sample filled in the measurement container. And a measurement step of measuring a high frequency capacity by bringing a measurement portion of the high frequency capacity moisture meter into contact with the surface of the sample of the ionized sample, and the high frequency capacity moisture meter A reference sample indicating the relationship between the indicated value and the moisture content of the reference sample or the ionized sample, and the addition sample are prepared, and a surface dry point at which the inclination of the addition sample changes with respect to the reference sample It comprises the table dry judging process which specifies and judges the surface dry state.

Thereby, the moisture meter which measures the moisture content of concrete is improved, and the electric field generated from the electrode plate reaches the concrete by changing the distance between the pair of electrode plates by measuring the capacitance. When the electric field is in the water repellent layer, the capacitance decreases at a constant rate, and when the electric field reaches the high water content simulated non-water repellent layer, the rate of decrease in capacitance changes. The inflection point is defined as the boundary between the water repellent layer and the ordinary layer, and a value relatively close to the measured value is obtained.
However, in the water containing concrete of Patent Document 1, pure H ₂ O is a good insulator, and when the pure H ₂ O is measured, the resistance decreases during the measurement. Also, along with that, the dielectric constant also changes depending on the metal ion, and changes as the frequency characteristic of conductivity and dielectric constant depending on the water content. Also, if the measurement target is a large volume, the electric field spreads and the electric field density changes depending on the position of the electrode plate, the area of the electrode plate, and the height of the applied voltage that determines the electric field. Calculation will be needed.

Therefore, the present invention is intended to provide a method for measuring the thickness of a water repellent layer , even if the resistance value and the dielectric constant change depending on the water content without changing the result depending on the water content. It is.

In the method of measuring the thickness of the water repellent layer according to the invention of claim 1, the two electrode plates having the electrode plate area S are paired, and the electrode plate area S and the horizontal distance t to the center position between the electrode plates and each electrode plate It is composed of an electrode having a ratio of the ratio to the area S and a isometric coplanar electrode constant S / t. A high frequency output is applied to both sides of a pair of equal ratio coplanar electrodes, and the capacitance C is measured. A characteristic of a specific linear function is obtained between a horizontal distance t to the center position of the electrode plates and a display value Cd measured at each electrode depending on the capacitance C, and a slope a of the characteristic of the linear function Is the inclination information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is output as initial information related to the moisture content near the surface layer.

Here, the ratio of the horizontal plane distance t of the test piece to the central position between the electrode plates and the electrode plate area S may be constant. In particular, it is the isometric coplanar electrode constant S / t that satisfies it. (However, even if the geometrical ratio coplanar electrode constant S / t is the same, except for the case where the pair of electrode plate areas are different.)
Further, the horizontal distance t of the above-mentioned equal ratio coplanar electrode constant S / t can be made equal to the facing average distance d between the facing electrode plates on the linear distance. However, it is preferable that the horizontal distance t and the facing average distance d be the same because they are determined by the electrostatic field and the electric field, and they should be offset by a calculation formula.
The slope of the characteristic of the linear function can be the slope of the characteristic or the reciprocal 1 / a of the inclination of the characteristic. In any case, high frequency output is applied to the equal ratio coplanar electrodes on both sides of the equal ratio coplanar electrode, and between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C It is sufficient to draw the characteristics of the linear function.

The invention of the method for measuring the thickness of a water repellent layer according to claim 1 is that the ratio of the electrode plate area S to the horizontal distance t to the center position of the electrode plates is as a pair of two electrode plates having an electrode plate area S. A high frequency output is applied to the equal ratio coplanar electrode of the equal ratio coplanar electrode constant S / t , and the characteristic between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C The slope a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the slope information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is near the surface layer Output as initial information related to the moisture content of

Therefore, when the water repellent layer formed with a small coating amount is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the water repellent layer formed with a small amount of application is thin, the slope a is large, and when it is thick, it decreases. Therefore, the reciprocal 1 / a of the slope of the regression line of each specimen is expressed as the water repellent layer You can also Regarding the relationship between the reciprocal 1 / a of the slope of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.
Therefore, a high frequency output is applied to the equal ratio coplanar electrode of the equal ratio coplanar electrode constant S / t, and a primary value is generated between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C. Taking the characteristic of the functional equation, (reciprocal number 1 / a) of the inclination of the characteristic of the linear functional equation is the inclination information related to the water repellent layer thickness, and the intercept of the display value Cd depending on the capacitance C b obtains an output as initial information related to the moisture content near the surface layer. Thereby, for example, the penetration depth and the like of the silane-based surface impregnated material are measured, and the water-repellent layer thickness of the silane-based surface impregnated material is measured as a regression line.

FIG. 1 is a basic explanatory view illustrating the method of measuring the thickness of the water repellent layer according to the embodiment of the present invention. FIG. 2 is a basic block diagram of the embodiment of the present invention. FIG. 3 is an explanatory view showing the relationship between the water content used in the embodiment of the present invention and the display value in the case where the simulated non-water repellent layer is constant. FIG. 4 is a characteristic diagram showing the relationship between the horizontal distance and the display value according to the simulated specimen used in the embodiment of the present invention. FIG. 5 is an explanatory view showing the relationship between the slope and the intercept of the regression line used in the embodiment of the present invention. FIG. 6 is a characteristic diagram showing the relationship of the intercept at each moisture content used in the embodiment of the present invention. FIG. 7 is a characteristic diagram showing the relationship of the reciprocal of the slope in each moisture content used in the embodiment of the present invention. FIG. 8 is an explanatory view showing the composition of the concrete sample to be measured in the embodiment of the present invention. FIG. 9 is an explanatory view showing the physical properties of the aggregate of the concrete sample to be measured in the embodiment of the present invention. FIG. 10 is a characteristic diagram showing the change of the capacitance of the concrete sample to be measured in the embodiment of the present invention. FIG. 11 is a characteristic diagram showing the reciprocal of the inclination and the water repellent layer thickness measured in the embodiment of the present invention. FIG. 12 is a characteristic diagram of the display value of the test sample of stationary day 1 having the inclined water content distribution measured in the embodiment of the present invention. FIG. 13 is a characteristic diagram of the display value of the specimen of stationary 7 days having the inclined water content distribution measured in the embodiment of the present invention. FIG. 14 is a measurement result diagram showing measured values and estimated values measured in the embodiment of the present invention.

Hereinafter, the method of measuring the thickness of the water repellent layer according to the embodiment of the present invention will be described based on the drawings. Note that, in the embodiment, the same symbols and symbols in the drawings are the same or corresponding functional parts, and therefore the description thereof will not be repeated here.

Embodiment
First, the basic principle of the method of measuring the thickness of the water repellent layer will be described.
In the present invention, a pair of electrodes is a parallel plate, and the configuration of a capacitor in which a dielectric of dielectric constant ε is sandwiched therebetween is used. The electrode plate area S of the parallel electrode plates is in the state of being disposed apart by the facing average distance d between the electrode plates opposite to each other in parallel. The capacitance C of the electrode plate of the electrode plate area S at this time is proportional to the dielectric constant ε of the dielectric between the electrode plate area S and the electrode plate, and the capacitance C of the electrode plate is S The capacitance C is expressed by the following equation.
C = ε · S / d
Where C (F) capacitance
S (m ² ) Electrode plate area between facing electrode plates
d (m) opposing average distance between opposing electrode plates
ε (F / m) is the dielectric constant of the dielectric between the electrode plates.

As the high frequency source, since the inventors are used to handling, a commercially available high-frequency capacitive moisture meter (HI-520: manufactured by Ketto Scientific Research Institute, Inc., high-frequency capacitive type (20 MHz)) electrodes 17 and 18 The high frequency output from was used.
In the experiments of the inventors, a high-frequency capacitive moisture meter is used instead of the LCR meter, but as a result, the value of the capacitance C is not measured, but the output is relayed. The capacitance C of the test material (aggregate) is not calculated based on the dielectric constant ε at a high frequency (20 MHz).
If a general LCR meter is used, it is necessary to consider the influence of stray capacitances of the electrodes 17, 18, etc. As a result, it is considered that a commercially available high frequency capacitive moisture meter is more useful.

First, when water is included in the aggregate of the test material, a phenomenon occurs in which the capacitance C increases with the increase of water. Usually, when the capacitance C is calculated from the dielectric loss tangent tan δ,
It is expressed by the current Ir of the resistance component / the current Ic of the capacitor capacitance component, and the equation is tan δ = Ir / Ic
It becomes.
However, the dielectric constant of about 80 of water changes with the change of temperature and also changes with the frequency applied, and a chemical reaction occurs and also changes with the application time and the like. This is largely due to the action of melting by ions and the like.
Moreover, although the electrostatic capacitance C is calculated as C = (epsilon) * S / d, the area | region pinched | interposed between electrodes can also be caught as a resistor.
Therefore, as the phenomenon, when the aggregate of the test material is made to contain water, the capacitance C increases with the increase of water, so it was decided to capture only that event.
The amount of increase in capacitance C as the water content increases is converted in accordance with a conversion formula previously obtained using mortar, concrete, and various other test materials, and is displayed as the water content. Here, in the test material having no conversion formula, the mode is switched to the direct mode (D mode) of a commercially available high-frequency capacitive moisture meter, and a numerical value correlated with the capacitance C is displayed as a display value Cd. As a precaution, the display value of the direct mode used by the inventors is displayed between "0 and 2999".

  A high frequency output (AC voltage) was applied to both electrode plates, and a band-like electric field was generated therebetween, and the capacitance C of the test material on this electric field was measured. The shape of the electric field is considered to be arc-like or elliptical depending on the boundary conditions etc. However, "It is possible to evaluate the amount of dielectric physical properties to a depth proportional to the electrode spacing (S. Tetsuro:" Since it is said that “Development diagnosis technology for polymer electrical insulation materials” (FY 2004-2006 Grant-in-Aid for Scientific Research Grants), the opposing distance d between the electrode plates and the depth of the electric field It was assumed that it was a circular arc shape that was simply proportional. The electrode plates were arranged in parallel so that the electric field was transmitted through the test material, and it was assumed that the depth at which the electric field reached would be changed by changing the facing average distance d between the electrode plates.

  Further, the dielectric constant ε of the dielectric changes in accordance with the water content. Further, the facing average distance d between the electrode plates is the facing average distance length of the arc-like electric field. When the facing average distance d between the electrode plates is small, the electric field exists only in the simulated water repellent layer 41, and the capacitance C decreases with the increase in the facing average distance d between the electrode plates. When the electric field reaches the simulated non-water repellent layer 42 having a high water content, the dielectric constant ε also changes, and the reduction rate of the display value Cd changes.

  Therefore, logically, this inflection point is the boundary between the simulated water repellent layer 41 and the simulated non-water repellent layer 42. The estimated value of the water repellent layer thickness at this time was close to the confirmed value confirmed by the measurement. However, if the simulated water repellent layer 41 is thin, an inflection point appears immediately, which makes it difficult to determine the inflection point. In addition, when the width of the electrode plate is narrowed for thin water-repellent layer thickness measurement, there is a disadvantage that the accuracy is lowered. That is, it is estimated that the electric field affects the side of the non-water repellent layer 42 from the beginning.

Next, the electrode plates 21, 22, 21A, 22A shown in FIG. 1 used in the embodiment of the present invention will be examined.
An electrode was manufactured such that the ratio S / t of the horizontal plate distance t from the center position of one electrode plate to the center position of the other electrode plate and the electrode plate area S was constant. An electrode in which the ratio S / t of the horizontal plane distance t to the electrode plate area S is constant is referred to as a "equal ratio coplanar electrode". Further, although the horizontal distance t is defined for the electrode plates 21, 22, 21A, 22A, it may be a vertical surface or may have a predetermined inclination. Here, in order to clarify the difference with the facing average distance d between electrode plates, it is called horizontal surface distance t. Here, S / t = const is referred to as "equal ratio coplanar electrode constant".

Here, a value obtained by multiplying the horizontal distance t by the circle ratio π is set as the facing average distance d between the electrode plates.
π · t = d
t = d / π
It becomes.
Therefore,
S / t = S · π / d
It becomes. The circle ratio π is constant, and the uniform coplanar electrode constant S / d is always constant.
In addition, the capacitance C is constant, if the dielectric constant ε, that is, the water content does not change in the depth direction, according to C = ε · S / d.
Then, when the horizontal distance t is sequentially increased, when the electric field reaches a portion with high water content, the capacitance C changes for the first time, and the value of the changed position becomes the depth of the simulated water repellent layer 41 .

The inventors further investigate iso-coplanar electrodes 21, 22, 21A and 22A (hereinafter, these will be collectively referred to as “e-coplanar electrode 20”).
Five types of equal ratio coplanar electrodes 20 having horizontal surface distances t of 4, 8, 12, 16, and 20 mm were produced. The electrode plate length of the equal ratio coplanar electrode 20 was constant at 100 mm, and the electrode plate width was changed to set the equal ratio coplanar electrode constant S / t = 100. In this case, since the width of the electrode plate offsets the horizontal distance t, the facing average distance d between the electrode plates and the horizontal distance t of the equal ratio coplanar electrode 20 are the same (the facing average distance d between the electrode plates d = horizontal distance t) And Here, electrode plates having different areas of the pair of equal ratio coplanar electrodes 20 were excluded.

As a material of an electrode plate, as shown in FIG. 2, the copper foil tape 10 was stuck on the plastic film 11, and also the plastic film 11 was stuck on the polystyrene foam 12 of 25 mm. Vinyl coated copper wires 15 and 16 were attached to the copper foil tape 10 as an electrode plate and extended, and brought into contact with the electrodes 17 and 18 of a commercially available high-frequency capacitive moisture meter. Although the lengths of the vinyl-coated copper wires 15 and 16 as lead wires are different in FIG. 2, they are uniform in length in the test circuit. The circuit has symmetry and is drawn out on the opposite side.
In particular, when both vinyl coated copper wires 15 and 16 are brought close to each other, they are influenced by the electrostatic stray capacitance and affect the displayed value Cd of the output, so they are separated from each other so that the influence becomes the minimum value. In order to electrically connect only the upper surface of the electrode 21A (21) and the electrode 22A (22) to the upper surface of the simulated sample, a wrap film 14 is applied to electrically insulate the other upper surface of the simulated sample.
Also, a 2 kg weight 13 was placed on the polystyrene foam 12 in order to bring the copper foil tape 10 into close contact with the test piece.

Using the equal ratio coplanar electrode 20 manufactured in this manner, a simulated specimen with a constant water content was manufactured, and the characteristics of the display value Cd of the carbon plate and the concrete were measured. A caikale plate is easily processed at a thickness of 5 mm, has a high water absorption rate, and has a high water absorption rate, and was adopted as a simulated specimen.
A sample of 5 mm in thickness x 100 mm in length x 100 mm in width is subjected to oven drying at 105 ° C. for 24 hours to obtain a water content of 0%. The sample was placed in a plastic bag with water of such a mass as to cause water absorption, and was then absorbed to make a sealed test sample. Then, as shown in FIG. 3, a caical plate having a moisture content of 0, 6, 12% when the whole of the simulated specimen was 100% was manufactured. In addition, concrete manufactured cubes with a moisture content of 0, 4 and 6.4%.

Here, since the bone dry plate has an absolute dry density of about 0.7 g / cm ³ , which is about 1/3 of that of concrete, the amount of water containing water is about 1⁄3 of that of concrete with the same water content. Eight equal carbon content plates having the same water content were stacked to prepare an equal ratio coplanar electrode 20, and the value of the display value Cd was measured.
The concrete was prepared by cutting a 100 × 100 × 400 mm concrete simulation specimen prepared with a 55% water / cement ratio into cubes of 100 mm square and saturated with water to obtain a surface dry state (water content: 6.4%) What was adjusted so that the moisture content and the moisture content of the same dimensions as that of the one were adjusted to 4.0% and 0% was put in a plastic bag and sealed, and water was uniformly adsorbed to obtain a simulated specimen of a predetermined moisture content.
Here, the relationship between the horizontal distance t of the simulated specimen and the display value Cd is shown in FIG.

As shown in FIG. 3, it can be seen that the display value Cd is substantially constant even if the horizontal surface distance t is changed, if the water content of the concrete and the carbon plate is constant. Once the indicated value Cd and the specimen such as concrete or caulcal plate are known, the moisture content of the specimen is specified. Here, it is presumed that the error of the indicated value Cd is due to the difference in the characteristic of the moisture content distribution to the caulcal board and the general relation of the concrete, and the difference in the moisture content depending on the individual.
In addition, even if the horizontal distance t to the electrode plate center position at each moisture content increases, it is confirmed that the value of the display value Cd does not change and becomes substantially constant even if the horizontal distance t decreases.
Then, if the equi-coplanar electrode constant S / t is constant, the dielectric constant ε (water content) changes even if the horizontal distance t to the electrode center position is increased and the position where the electric field reaches is deepened. If not, the display value Cd is the same value. Then, the result was obtained that the value of the display value Cd becomes larger as the moisture content becomes higher. From this, it can be seen that the indicated value Cd depends on the water content.

Next, measurement of the simulated specimen of the simulated water repellent layer 41 is performed using this equal ratio coplanar electrode 20.
1 or 2 or 3 sheets of 0, 6 and 12% silicon plates are placed on the concrete cubes with water content of 6.4% and 4.0% shown in FIG. 2 and FIG. 3, and lamination of each electrode plate The display value Cd was measured in the state. The carbon plate is a two-layer simulated specimen model in which the simulated water repellent layer 41 having a low water content is simulated, and the concrete non-water repellent layer 42 having a high water content is simulated.

As shown in FIG. 4, one, two, three, or four pieces of silicon boards with a moisture content of 0% are stacked on concrete having a dielectric constant ε and a moisture content of 6.4%, and the horizontal distance t to the electrode plate center position and each display The relationship of the value Cd is illustrated.
As shown in FIG. 4, the inclination of the straight line is large when the thickness of 5 mm of the silicon plate is as thin as one, and the inclination is small when the thickness of three laminated sheets is 15 mm.
Further, the intersection point of the y-axis intersecting the y-axis at x = 0 which does not depend on the thickness of the caiscal plate, that is, the intercept b of the display value Cd is substantially the same value. The value showed a value close to the indicated value Cd = 1270 in the case of overlapping the silica plates having a water content of 0% shown in FIG. A linear relationship with other water content scale plates, that is, a linear function equation of display value Cd Display value Cd = ax + b = ax + 1270
The display value Cd is the vertical axis (y), and x is the horizontal axis.
was gotten. The intercept b of the indicated value Cd is shown in FIG.
The slope of each straight line obtained by linear regression of the relationship between the display value Cd and the horizontal distance t obtained by changing the moisture content of concrete and caycal board and the number of stacked caical boards and changing it. An intersection point of a and x = 0 y axis (display value Cd) is a display value Cd.

The larger the difference between the moisture content of the cical plate regarded as the simulated water repellent layer 41 and the moisture content of concrete regarded as the simulated non-water repellent layer 42, the larger the inclination of the regression line. It is considered that if the impedance of the capacitance Ca of the caical plate and the impedance of the capacitance Cb of concrete are considered to be connected in series, when Ca 接 続 Cb by the comparison of impedances, the capacitors are connected in series The amount of work is dependent on Ca, which has a large capacitance impedance.
In particular, when the moisture content of concrete is 4% and the moisture content of the cical plate placed above is 12%, the difference between the moisture content of the two is not so large, the inclination becomes negative when the number of cical plates is increased. , The correlation coefficient of the regression line also decreases.
In addition, when the thickness of the simulated water repellent layer 41 was large, that is, as the number of the silica plates was increased, the inclination was reduced. In the case where the moisture content of the caycal plate is the same, as shown by the relationship between the moisture content and the segment shown in FIG. 6, the values of the segment b become substantially the same even if the number of overlapping sheets is changed. In particular, since the water content is constant and there is no change in the water content, it is estimated that the same can be obtained regardless of how many sheets are used.
Also, it is considered that the simulated water repellent layer 41 is a desirable measurement method because the moisture content is very small.

In addition, in the case of three caical plates (15 mm thick), the display value Cd does not change with electrodes having a horizontal distance t of 4 mm and 8 mm, so the electric field has a large effect on the simulated non-water repellent layer 42 with high moisture content It is presumed that there is no
Although it was estimated that the display value Cd would increase rapidly at 12 mm and 16 mm or more starting to reach the simulated non-water repellent layer 42, the display value Cd would increase continuously and a linear relationship was obtained between the horizontal distance t and the display value Cd. No continuous points occurred. The electric field shape is also presumed to be an arc when the electrode plates face each other in the opposite state, but the electric field in the sample is the same as the sum of the capacitances as impedances connected in series between equal ratio coplanar electrodes 20. Detailed analysis, such as investigation of the influence of the difference in the shape of the water content and the moisture content, will be the subject for future study.

The moisture content of the caking plate piled up at 6% and 4% of the concrete content, the reciprocal of the slope 1 / a of the regression line obtained by changing the thickness of the caking plate with 0% and 12%, respectively The relationship with the thickness of the caycal plate is shown in FIG. The linear relationship which can be shown by a linear function equation was obtained for the reciprocal 1 / a of the slope and the thickness of the caycal plate, respectively.
From this, if the relationship between the reciprocal 1 / a of the slope and the thickness of the water repellent layer is determined in advance for each sample, the regression line of the horizontal distance t and the display value Cd obtained by measuring with the equal ratio coplanar electrode 20 The water repellent layer thickness can be estimated from the slope a or the reciprocal 1 / a of the slope.

Next, it examines using the example of these obtained simulated specimens.
First, a concrete simulation sample on which a simulation water repellent layer 41 was formed was measured with a uniform ratio coplanar electrode 20, and the reciprocal 1 / a of the slope of the regression line as obtained for the simulation sample and the water repelling layer thickness Examine the relationship.
The concrete used three types of compounding. The composition of the concrete and the 28-day compressive strength are shown in FIG.
The water to cement ratio (referred to as W / C in FIG. 8) was 40, 55, 70%. Relatively low quality such as ordinary concrete with 55% water / cement ratio and 5% air content, which are used in general structures, and 40% water / cement ratio assuming relatively high strength The amount of air can be reduced without using an AE agent (a type of surfactant, an additive that improves the efficiency of concrete placement and the freeze resistance) at a low water-cement ratio of 70% assuming concrete. It was decided to be. The cement used was early-strength cement.
The physical properties of the used aggregate are shown in FIG. The coarse aggregate used grated stone from Nagara River, and the fine aggregate was a mixture of coarse sand and fine sand from Nagara River at a ratio of 7: 3.
Here, s / a is a fine aggregate rate (the ratio of the volume of the fine aggregate to the volume of the total aggregate), and in this case, s / a = 40%. Moreover, S1 is a coarse thing among fine aggregates, S2 is a fine thing among fine aggregates, G is a coarse aggregate.

As shown in FIG. 8, two types of curing were used: curing in water and curing in air for 28 days after demolding.
A specimen of a square column of 100 mm × 100 mm × 400 mm was prepared, and after curing, it was cut using a concrete cutter to make 50 mm × 100 mm × 130 mm. After making a bank on a 100 mm × 130 mm cut surface so that the surface impregnating material does not drip on the side surface of the sample, it was dried in an oven to be completely dried, and further, the surface impregnating material was applied.
The surface impregnating material is manufactured by TOOKEN CHEMICAL CO., LTD. (Product name S-7; hereinafter simply referred to as "made by T company") and Daido Paint Co., Ltd. (product name aqua seal 1400; hereinafter referred to simply as "made by company D") Was used. The product of company T is liquid, and the product of company D is gel.
Both of the components were silanes, and the standard amount used was 200 g / m ² . The coating amount was set to ^{100g / m 2 ~500g / m 2} , a portion of the specimen number was applied 50 and 800 g / ^{m 2.} The number of specimens was 68 in all.

After leaving for 4 days or more after application so as to form the simulated water repellent layer 41, the sample was placed in a container and immersed in water. The depth of water was set to the height of the specimen, and water was allowed to absorb from the bottom and the side of the specimen for 4 days. The simulated water repellent layer 41 has a very low water absorption rate, and the simulated non-water repellent layer 42 has a high water absorption rate, so the simulated water repellent layer 41 has a small water content like the simulated sample and the simulated non water repellent layer has a high water content. Forty-two two-layer specimen models were constructed.
Fig. 10 shows that 100, 300, 500 g / m ² of surface impregnated material from T Co. is applied to those cured in water at a cement ratio of 55% with water, but the horizontal distance t to the electrode plate center position and the indicated value Cd Show the relationship between It shows that a linear relationship (linear characteristic) can be obtained in the display value Cd depending on the horizontal distance t to the electrode plate center position and the capacitance C as in the case of the simulated specimen.
After the measurement, each sample was split and the actually formed water repellent layer thickness was measured. The measurement averaged the value in the center part and the part of the position of 25 mm on both sides. When the simulated water repellent layer 41 formed with a small coating amount is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b has substantially the same value, and the water content of the water repellent layer portion is considered to be the same.
The coating amount of the surface impregnating material is 100, 300 and 500 g / m ² , but the inclination a is large when the water repellent layer formed with a small coating amount is thin, and is small when it is thick.
In this way, the slope a is obtained as a linear function of the relationship between the display value Cd measured by the electrode shown in FIG. 10 and the distance t to the center of the electrode. As in the case of 4.8 mm, 10.2 mm and 14.0 mm in FIG. 10, the sample is divided to obtain the actual water repellent layer thickness.

Furthermore, FIG. 11 shows the relationship between the reciprocal 1 / a of the slope of the regression line of each simulated specimen and the measured value of the water repellent layer thickness.
The Y axis in Figure 11 uses the water repellent layer thickness actually measured by dividing the sample, and the X axis uses the reciprocal 1 / a of the slope a to obtain a linear function.
As a formula,
The water repellent layer thickness is 164.5 × (1 / a) + 1.302.
If the sample whose water repellent layer is unknown is measured with an electrode and the inclination a is obtained, the water repellent layer can be determined from this equation.
In FIG. 11, the number of test specimens is 68, which is the sum of simulated test specimens coated with T company and D company. The reciprocal 1 / a of the slope is confirmed from the water repellent layer thickness X measured by making the reciprocal 1 / a of the slope of each simulated specimen and the intercept b of the measured value of the water repellent layer common to the indicated value Cd. Be done.
Therefore, the reciprocal 1 / a of the slope is determined from the straight line of the linear function equation expressed by the 68 data, and if the reciprocal 1 / a of the slope is identified, the water repellent layer thickness is identified.
A linear relationship was obtained for the reciprocal of the slope and the water repellent layer thickness as in the case of the simulated specimen. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.

Next, a method of measuring the thickness of the water repellent layer assuming an actual structure will be described.
In the sample described above, the simulated water repellent layer 41 has a low moisture content, and the simulated non-water repellent layer 42 has a two-layer sample model with a high moisture content close to the surface dry state.
However, in an actual structure, the water content is not a two-layer sample model, but is estimated to be a slope distribution in which the vicinity of the surface is low and the height gradually increases toward the center. Assuming a slope distribution, the prismatic specimen cured in water at a cement ratio of 55% with water is divided into two equal parts, and those sealed with a rubber-based paint to prevent entry and exit of water except for the cut surface are immersed for 3 days, It stood still in the laboratory for 7 days and 1 day. Two of them were allowed to stand.
The seven-day Gifu Meteorological Observatory records that this test was conducted showed an average temperature of 6.3 ° C and an average humidity of 62%. After standing, 200 g / m ^{2 of a} surface impregnating material manufactured by D was applied to the cut surface. The indicated value Cd was measured with the electrode before application and 4 days after application.
After the measurement, it was split to measure the simulated aqueous layer depth. The relationship between the horizontal distance t to the electrode center before application and after application and the display value Cd is illustrated.

As for what was dried for 1 day, as shown in FIG. 12, the display value Cd before application becomes a value close to the display value Cd = 1900 of the surface dry state (water content 5.2%) even when the horizontal distance t is 4 mm. Most of the water is not evaporated, and it is presumed to be in a saturated state. Although the indicated value Cd decreased even after the application, it was an almost constant value and a clear slope was not obtained, and the water repellent layer thickness could not be estimated.
The estimation of the water repellent layer thickness in a moisture content distribution with a slope assuming an actual structure may have few experimental examples and may need to be corrected in the future. In the future, it is necessary to further study, such as changing the moisture content.

In addition, as shown in FIG. 13, the display value Cd before application is as low as 1900 at a horizontal distance t of 4 mm, the display value Cd is as low as 1900, and is substantially the same for 8 mm or more. It has become. The indicated value Cd at 8 mm or more is a value close to the indicated value of the concrete in the surface dry state (water content: 6.4%) shown in FIG. 3, and it is considered that the inside is saturated.
After application, the display value Cd decreased at 4, 8 and 12 mm, and became a value close to the value before application at 16 mm or more. Linear regression was performed using the value up to 16 mm at which the increase in the display value Cd after application almost disappeared, and the slope a was determined. An estimated value and an actual measurement value obtained by estimating the water repellent layer thickness from the relationship between the inverse 1 / a of the slope and the water repellent layer thickness using the slope a are shown in FIG. The estimated value and the measured value show relatively close values.

In the method of measuring the thickness of the water repellent layer according to the above-mentioned embodiment, two sheets of the same electrode plate area S are paired, and the ratio of the horizontal distance t to the center position between the electrode plates is equal ratio coplanar electrode constant S / t A high frequency is applied to the equal ratio coplanar electrode 20 and the equal ratio coplanar electrode 20 on both sides, and the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C based on the high frequency The linear function equation Y = aX + Cd characteristic is obtained between them, and the output is obtained as the inclination a or the inverse 1 / a of the characteristic of the linear function as inclination information related to the water repellent layer thickness.
Here, by measuring gypsum board, concrete, ALA concrete (artificial lightweight aggregate concrete), ALC, mortar, calcium silicate board, D mode, S mode characteristics, as initial information related to the moisture content near the surface layer An intercept b of the display value Cd is calculated.
Further, if the reciprocal 1 / a of the slope in the characteristic of the linear function equation is the inclination information related to the water repellent layer thickness, and if the reciprocal 1 / a of the inclination of the characteristic of the known linear function equation is set as a standard In addition, if the point at which the display value Cd dependent on the capacitance C matches is determined, the water repellent layer thickness can be calculated.

In the method of measuring the thickness of the water repellent layer according to the above embodiment, two sheets of the electrode plate area S are a pair, and the ratio of the ratio of the horizontal plate distance S to the electrode plate area S to the center position between the electrode plates is equal ratio A characteristic between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, for example, adding a high frequency output of 20 MHz to the equal ratio coplanar electrode of the plane electrode constant S / t. The slope a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the slope information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is near the surface layer The output is obtained as the initial information related to the moisture content of
At this time, the 20 MHz of the high frequency is not limited to the 20 MHz, and may be an alternating current. However, if the frequency is low, a chemical reaction such as electrolysis of water occurs, and if the frequency is high, a magnetic field can not be generated inside the dielectric, and the magnetic field on the outer surface becomes high.
Also, although the characteristics of the linear functional equation are preferably linear, they can not be used non-linearly. Therefore, when the simulated water repellent layer 41 formed with a small coating amount is thin, the inclination a may be large, and when it is thick, the inclination a may be small.

Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the simulated water repellent layer 41 formed with a small amount of application is thin, the slope a is large, and when it is thick, it decreases. Therefore, the reciprocal 1 / a of the slope of the regression line of each sample is It can also be expressed as Regarding the relationship between the reciprocal 1 / a of the slope of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.
Therefore, between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, high frequency power is applied to the equal ratio coplanar electrode having a constant equal ratio coplanar electrode constant S / t. The characteristic a of the linear function equation is obtained, and the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation is used as the inclination information related to the water repellent layer thickness. The intercept b of b provides an output as initial information related to the moisture content near the surface layer. Thereby, for example, the penetration depth and the like of the silane-based surface impregnated material are measured, and the water-repellent layer thickness of the silane-based surface impregnated material is measured as a regression line.

Horizontal distance t geometric coplanar electrodes constant S / t of the thickness measuring method of the water-repellent layer of the above-described embodiment, since those were the same as opposed average distance d of the opposing electrode plates, geometric co Since the horizontal distance t satisfying the surface electrode constant S / t and the value obtained by multiplying the horizontal distance t by the circular ratio π are the same as the opposing average distance d between the electrode plates, the electric field draws an arc. The opposing average distance d between the electrode plates can be calculated as a regression line at the center position of the arc.
Further, since the inclination of the characteristic of the linear function equation of the above embodiment is the inverse 1 / a of the inclination of the characteristic, the inverse 1 / a of the inclination of the characteristic of the linear function equation is a water repellent layer The inclination information is related to the thickness, and the intercept b of the display value Cd depending on the capacitance C is an output as initial information related to the moisture content near the surface layer.

In the method of measuring the thickness of the water repellent layer according to the above embodiment, two sheets of the electrode plate area S are paired, and the ratio of the horizontal distance t to the center position between the electrode plates is equal ratio coplanar electrode constant S / t. A high frequency output is applied to the equal ratio coplanar electrodes and the equal ratio coplanar electrodes on both sides except that the area of a pair of equal ratio coplanar electrodes is different, and the horizontal distance t to the center position between the electrode plates Obtain a characteristic of a linear function equation with a display value Cd depending on the capacitance C, and output the inclination a (reciprocal number 1 / a) of the characteristic of the linear function equation as the inclination information related to the water repellent layer thickness To get
With the exception of the cases where the areas of the pair of equal ratio coplanar electrodes are different from those of the equal ratio coplanar electrodes, the electrode plates of the two equal ratio coplanar electrodes even if they satisfy the equal ratio coplanar electrode constant S / t. It means that the areas S are different from each other.

The invention of the method of measuring the thickness of the water repellent layer according to the above embodiment is characterized in that the two electrode plate areas S are paired and the ratio of the ratio of the electrode plate area S to the horizontal distance t to the center position of the electrode plates is equal. By applying a high frequency output to the equal ratio coplanar electrode of the coplanar electrode constant S / t, and obtaining the characteristic between the horizontal distance t to the center position between the electrode plates and the display value Cd depending on the capacitance C, The slope a (reciprocal number 1 / a) of the characteristic of the linear function equation is the slope information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is the moisture content near the surface layer Get the output as the relevant initial information.
The display value Cd dependent on the capacitance C is specified, and the water repellent layer thickness is calculated from the specified display value Cd.

  Therefore, when the simulated water repellent layer 41 formed with a small amount of application is thin, the inclination a is large, and when it is thick, the inclination a is small. Further, the intercept b of the display value Cd depending on the capacitance C is substantially the same, and the water content of the water repellent layer portion is considered to be the same. When the water repellent layer formed with a small amount of application is thin, the slope a is large, and when it is thick, it is small. Therefore, the reciprocal 1 / a of the slope a of the regression line of each sample is the water repellent layer thickness. It can also be expressed. Regarding the relationship between the reciprocal 1 / a of the slope a of the regression line of each sample and the water repellent layer thickness, a linear relationship was obtained between the reciprocal of the slope and the water repellent layer thickness. The effect of the type of surface impregnating material, the composition of concrete, and the difference in curing conditions did not appear.

Therefore, a high frequency output is applied to the equal ratio coplanar electrode of the equal ratio coplanar electrode constant S / t, and a primary value is generated between the horizontal distance t to the center position of the electrode plates and the display value Cd depending on the capacitance C. The characteristic of the functional equation is obtained, and an output is obtained as the inclination a (reciprocal number 1 / a) of the characteristic of the linear functional equation as inclination information related to the water repellent layer thickness. Thus, for example, the penetration depth and the like of the silane-based surface impregnated material were measured, and in the present embodiment, the water-repellent layer thickness of the silane-based surface impregnated material was measured as a regression line.
In particular, the capacitance C is inversely proportional to the facing average distance d between the electrode plates, ie,
C = ε · S / d
When the region of capacitance C is confirmed as a resistor, the measurement electrode for measuring the difference in moisture content between the inside of the sample and the surface layer portion and the measurement method using the measurement electrode are confirmed. be able to.
The display value Cd depending on the capacitance C may be a capacitance C depending on a frequency, or may be simply a capacitance C depending on a frequency.

In the present embodiment, the case of applying the silane-based surface impregnating material has been described, but in the case of carrying out the present invention, the measurement is based on the premise that the silane-based surface impregnating material is not impregnated with water, It can be generally used without being limited to the silane surface impregnation material.
In addition, when the sample is made to absorb the simulated water repellent layer 41 in concrete and the condition is similar to the two-layer simulated sample model same as the simulated sample, the slope of the regression line is the same as the simulated non-water repellent layer 42 A linear relationship was obtained between the reciprocal of and the water repellent layer thickness.
And, according to the experiments of the inventors, the characteristics of the test specimen as the simulated test specimen in advance are gypsum board, concrete, ALA concrete (artificial lightweight aggregate concrete), ALC, mortar, calcium silicate board, D mode, S mode It had to be used as a property. Moreover, when the water repellent layer thickness was estimated by the manufacturer of the surface impregnating material, it showed close values, but there is a possibility that it may be different. It is thought that further examination is needed by changing the

10 Copper foil tape (electrode)
11 Plastic film 12 Polystyrene foam 14 Wrap film 15, 16 Vinyl-coated copper wire 17, 18 Electrode of high-frequency capacitive moisture meter 20 Equi-planar electrode 21, 22, 21A, 22A Electrode plate 31, 32, 33 Simulated water repellent layer 41 Simulated water-repellent layer 42 Simulated non-water-repellent layer t Horizontal distance d Countering average distance S between opposing electrode plates Electrode plate area C between opposing electrode plates Capacitance ε Dielectric constant S of dielectric between electrodes t equal ratio coplanar electrode constant

Claims (4)

The two electrode plates of the electrode plate area S are paired, and the ratio of the horizontal plane distance t to the center position of each electrode plate of the pair of electrode plate areas S and the pair of electrode plate areas S is equal A uniform ratio coplanar electrode having a constant surface electrode constant S / t;
A high frequency is applied to the pair of equal ratio coplanar electrodes, and a characteristic of a linear function equation is obtained between a horizontal distance t to the center position of the electrode plates and a display value Cd depending on the capacitance C. ,
The slope a (reciprocal number 1 / a) of the characteristic of the linear function equation is the slope information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is the moisture content near the surface layer A measurement electrode for measuring a difference in moisture content between the inside of a specimen and a surface layer portion characterized in that an output is obtained as related initial information.   The horizontal distance t between the equal ratio coplanar electrode constant S / t is the same as the facing average distance d between the facing electrode plates, and the surface and the surface of the specimen according to claim 1. Measurement electrode to measure the difference in moisture content.   The inclination of the characteristic of the linear function equation is the inverse 1 / a of the inclination of the characteristic, and the difference between the moisture content of the inside of the sample and the surface portion according to claim 1 or 2 Measurement electrode to measure. The two electrode plates of the electrode plate area S are paired, and the ratio of the horizontal plane distance t to the center position of each electrode plate of the pair of electrode plate areas S and the pair of electrode plate areas S is equal A uniform ratio coplanar electrode having a constant surface electrode constant S / t;
A high frequency is applied to the pair of equal ratio coplanar electrodes, and a characteristic of a linear function equation is obtained between a horizontal distance t to the center position of the electrode plates and a display value Cd depending on the capacitance C. ,
The slope a (reciprocal number 1 / a) of the characteristic of the linear function equation is the slope information related to the water repellent layer thickness, and the intercept b of the display value Cd depending on the capacitance C is the moisture content near the surface layer What is claimed is: 1. A measurement method using a measurement electrode for measuring a difference in moisture content between the inside of a specimen and a surface layer portion, which is output as related initial information.

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