JP6011919B2 - Method for evaluating the quality of porous materials - Google Patents

Description

  The present invention relates to a quality evaluation method and a quality evaluation apparatus for non-destructive porous materials such as concrete and mortar.

  Conventionally, concrete, which is a main structural material in the civil engineering / architecture field, has been considered to have a compressive strength obtained by a compressive fracture test as an index representing quality, and quality evaluation or quality control based on compressive strength has been made. In addition, the quality of concrete in terms of durability has been qualitatively estimated from information such as blending at the time of concrete production, for example, a water cement ratio which is a mixing ratio of water and cement. However, in structural concrete that has been actually constructed and hardened, although there is no problem in compressive strength, blending, etc., deterioration factors such as carbon dioxide and salinity are higher than expected due to insufficient compactness. There are many cases that cause durability problems such as early invasion and early deterioration. Thus, although the compressive strength of concrete is an important design index as a structural material, it does not necessarily match an evaluation index for considering the durability of concrete, such as resistance to material deterioration. Therefore, not only information such as compressive strength and blending, but also quality evaluation regarding the durability of concrete is required.

JP 2012-26883 A

  What is considered as an index having a great influence on the durability of concrete is resistance to movement of various substances such as carbon dioxide, chloride ions, and water. In general, evaluation is performed based on concepts such as air permeability, water permeability / water absorption, chloride ion diffusion and neutralization rate. However, when these evaluations are performed on concrete in the actual structure, the method of damaging the actual structure, that is, sampling the core specimen, is limited in terms of cost, appearance, and structural reasons. There are many cases. Various methods for nondestructively evaluating the quality of air permeability, water permeability and water absorption have also been proposed. However, in any method, power supply equipment is required.For example, preparation and execution of the inspection require labor, and the interpretation of the evaluation values obtained by each method requires expertise because of non-destructiveness. . Therefore, it is difficult to say that these nondestructive inspection methods have been widely put into practical use. At present, the quality evaluation and management of concrete in an actual structure is limited to the compressive strength obtained by the destructive test of the cylindrical specimen prepared at the same time as the construction.

  Moreover, the nondestructive inspection of the above concrete has the following problems.

  The air permeability test evaluates the density of the concrete structure by forcibly moving the air in the concrete. This test has been developed and proposed outside the country, where a sample is taken in a laboratory and an actual structure is measured by an apparatus / method called the torrent method. In these methods, a suction cup or the like is installed on the concrete measurement surface, and the air in the concrete is forcibly moved by reducing the pressure in the cup. Since the substance to be moved is air, it is theoretically difficult to control the moving range of air. In addition, since the influence range is invisible, there are many error factors. Moreover, since this measurement has expertise, it lacks versatility. Furthermore, there are variations due to the presence of cracks on the concrete surface and the effect of the moisture state inside. Moreover, since it takes time to prepare for warm-up operation or the like due to the device configuration, there are many practical problems because it takes several tens of minutes for a single measurement. In addition, although the device is commercially available, it is very expensive at several million yen and cannot be easily introduced as an inspection device.

  The water permeability / water absorption test involves passing water through concrete, and a method of collecting a sample in the laboratory and a simple water absorption test method applicable to the field have been devised. Since these tests are affected by cracks and internal moisture in the same manner as the air permeability test, there is a problem in measurement accuracy. In addition, a simple water absorption test method that is applicable to the field requires power supply equipment to fix the device, and it takes time to install a measuring instrument, so the time required for one measurement needs to be several tens of minutes. There are many practical issues such as. As with the air permeability test, the device is expensive and cannot be easily introduced as an inspection device.

  There is also a method in which an identification material is applied to the surface of the porous material, and the denseness is evaluated by the color of the surface (see Patent Document 1). While this method can distinguish between porous materials having a large quality difference, it is not sufficient to distinguish porous materials having a small quality difference.

  Therefore, an object of the present invention is to provide a quality evaluation method and a quality evaluation apparatus for a porous material that can easily perform quality evaluation of the porous material on site.

  Another object of the present invention is to provide a porous material quality evaluation method and a porous material quality evaluation apparatus that accurately measure the quality of the porous material.

  Hereinafter, the features of the present invention will be described with reference numerals. Note that the reference numerals are for reference, and the present invention is not limited to the embodiments.

The quality evaluation method of the porous material according to the first feature of the present invention is to apply the identification material (L) to the surface of the target portion (M) of the porous material (P) and provide the identification material (L). Maximum color difference measurement time (T _L ) or maximum color difference measurement time as the elapsed time from the time when the surface color of the porous material (P) is measured and the identification material (L) is applied until the maximum color difference is shown. (T _L ) The surface color restoration speed maximum value (V _H ) is determined as the maximum value of the surface color change amount per unit time after (T _L ), and the maximum color difference measurement time (T _L ) or the surface color restoration speed maximum value ( The quality of the porous material (P) is determined based on _VH ).

In the above first feature, the identification material (L) is repeatedly applied to the surface of the target portion (M) of the porous material (P) a plurality of times, and the maximum color difference after the identification material (L) is applied a plurality of times The quality of the porous material (P) is determined based on the measurement time (T _L ) or the surface color restoration speed maximum value (V _H ).

  The identification material (L) is a liquid, and the flow distance (X1... Xn) of the liquid (L) from the target part (M) is measured, and the porous material is based on the flow distance (X1... Xn). The quality of (P) is determined.

The quality of the porous material based on the number of repetitions until the maximum color difference measurement time (T _L ), the surface color restoration speed maximum value (V _H ), or the flow-down distance (X1... Xn) reaches a predetermined value. May be determined.

The porous material quality evaluation apparatus (10) according to the second feature of the present invention is a colorimetric apparatus (11) for measuring the temporal change of the surface color of the porous material (P) provided with the identification material (L). And the maximum color difference measurement time (T _L ) as the elapsed time from the application of the identification material (L) to the maximum color difference, or the maximum value of the color difference change per unit time after the maximum color difference measurement time Determination device (13) for determining the surface color restoration speed maximum value (V _H ) of the material and determining the quality of the porous material (P) based on the maximum color difference measurement time (T _L ) or the surface color restoration speed maximum value Have

  According to the characteristics of the present invention, it is possible to evaluate the porous material of the actual structure on the site without damage, quickly and easily without the influence of cracks and the like.

  Further, the quality of the porous material can be clearly distinguished by repeating the application of the identification material a plurality of times.

  Furthermore, the quality of the porous material can be accurately evaluated by evaluating the flow distance.

It is a schematic diagram which shows the component of the quality evaluation apparatus of the porous material which concerns on embodiment. (A), (B), (C) is a schematic diagram showing a method for quality evaluation of a porous material. It is a schematic diagram which shows the method of measuring the flow distance of the liquid of the porous material surface. It is a flowchart which shows the process sequence of the quality evaluation method of a porous material. It is a graph for demonstrating the maximum color difference measurement time used for the quality evaluation method of a porous material, and the surface color restoration speed maximum value. It is a graph which shows the relationship between the maximum color difference measurement time shown in FIG. 5, the surface color restoration speed maximum value, and the amount of water absorption. (A), (B) is a graph which shows the relationship between the curing condition of concrete, the maximum color difference measurement time, and the surface color restoration speed maximum value in one watering. (A), (B) is a graph which shows the relationship between the elapsed time after watering and the color difference of the concrete surface. It is a graph which shows the relationship between the curing condition of concrete, the maximum color difference measurement time, and the surface color restoration speed maximum value in the watering of 3 times. (A), (B) is a graph which shows the relationship between the elapsed time after watering, and a color difference in the case of repeating watering. It is a graph which shows the relationship between the frequency | count of repeating watering, and the surface color restoration speed maximum value. It is a graph which shows the relationship between the frequency | count of repeating watering, and a flow-down distance.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

  As shown in FIG. 1, a quality evaluation device 10 for a porous material includes a color measurement device 11 that measures the color of the surface of the porous material, and a length measurement device 12 that measures the flow-down distance of the liquid applied to the porous material. A quality determining device 13 for determining the quality of the porous material, a storage device 14 for storing the measurement result and the determined quality, an input device 15 for inputting information on the porous material, a surface color of the porous material, An output device 16 is provided for outputting the flow-down distance and quality.

  Here, the porous material includes an inorganic material, an organic material, and a metal material. The inorganic material is, for example, concrete, mortar, or ceramic.

The color measuring device 11 is, for example, a colorimeter or a color difference meter, and spectroscopically reflects the reflected light of the porous material to determine the surface color. Here, as the surface system, for example, the RGB color system and the XYZ color system are used in addition to the L ^* a ^* b ^* color system. The color measuring device 11 measures the temporal change of the surface color of the porous material before the identification process and the surface color of the porous material after the identification process. Here, the identification process is to apply a liquid (water, colored water, component-containing water, organic solvent) identification material to the surface of the porous material and absorb or adsorb it. Further, the colorimetric device 11 may use a photographing device such as a digital video camera.

  The length measuring device 12 uses, for example, a laser displacement sensor using a triangulation method. The length measuring device 12 measures the flow-down distance from the target site to which the liquid is applied to the location where the liquid reaches. Further, the length measuring device 12 may use a length measuring instrument such as a major, or a photographing device such as a digital video camera.

  The quality determination apparatus 13 includes a CPU (Central Processing Unit) that processes data according to a processing program, a ROM (Read Only Memory) that stores the processing program, and a RAM (Random) that temporarily stores data necessary for the processing of the CPU. (Access Memory). The CPU calls the processing program from the ROM, determines the maximum color difference measurement time and surface color restoration speed maximum value from the surface color change over time, and is porous based on the maximum color difference measurement time, surface color restoration speed maximum value, and flow-down distance. Determine the quality of the material. Here, the relationship between the quality of the porous material and the maximum color difference measurement time, the surface color restoration speed maximum value, and the flow-down distance is determined in advance.

  The storage device 14 uses, for example, a hard disk, CD, DVD, or USB memory. The storage device 14 stores the temporal change of the surface color of the measured porous material and the flow-down distance.

  The input device 15 is, for example, a keyboard, a mouse, or a touch display. The output device 16 is, for example, a liquid crystal display device, an image display device such as an organic EL (Electro-Luminescence) display device, and an ink jet printer type or laser printer type printing device.

  The principle of the quality evaluation method of the porous material using the surface color will be described.

  As shown in FIG. 2A, for example, when the liquid L is applied to the target portion M of the porous material P, a part of the liquid L is absorbed by the porous material P, and the surface color of the target portion M changes. To do. When the same amount of liquid is sprayed on the high-quality and low-quality porous materials, the low-quality porous material absorbs liquid more easily than the high-quality porous material. Therefore, the amount of change in the surface color of the low-quality porous material is larger than the amount of change in the surface color of the high-quality porous material.

Further, the high quality porous material is longer than the low quality porous material with respect to the elapsed time (maximum color difference measurement time T _L (see FIG. 5)) from application of the liquid to the maximum color difference. In addition, regarding the maximum value of the time change amount that the porous material recovers from the maximum color difference (surface color recovery speed maximum value V _H (see FIG. 5)), the low-quality porous material is larger than the high-quality porous material. Become. From the above, the quality of the porous material can be determined using the maximum color difference measurement time T _L and the surface color restoration speed maximum value V _H. Further, the quality of the porous material can be clearly distinguished by repeatedly applying the liquid to the porous material. For example, since the low-quality porous material and the high-quality porous material have greatly different tendency of change in the surface color restoration speed maximum value V _H when the liquid is repeatedly applied (see FIG. 11), The quality of the porous material can be clearly distinguished by the number of repetitions required until the surface color restoration speed maximum value V _H converges to zero.

  The principle of the porous material quality evaluation method using the flow-down distance will be described.

  As shown in FIG. 3, when the liquid L is applied to the target site M on the surface of the porous material P, the porous material P absorbs a part of the liquid L, and the remaining liquid L1 passes from the target site M to the porous material. Down the surface of the. Here, a dense and high-quality porous material with few pores hardly absorbs liquid, the amount of liquid flowing down increases, and the liquid flowing distance from the target site increases. On the other hand, a low-quality porous material with many pores absorbs liquid easily, and the amount of liquid flowing down is small, and the flowing distance of the liquid from the target site is smaller than the flowing distance of the high-quality porous material. . Therefore, the flow-down distance of the high-quality porous material is larger than the flow-down distance of the low-quality porous material. Thereby, the quality of the porous material can be determined from the flow-down distance.

  Furthermore, when liquid is repeatedly applied to the target portion M of the porous material P, the flow-down distance of the liquid from the target portion M increases. By the second application of the liquid, the liquid L2 extends from the arrival position of the first liquid L1 by the distance of the difference between X2 and X1. Similarly, by the third liquid application, the liquid L3 extends from the arrival point of the second liquid L2 by the distance of the difference between X3 and X2. The distances from these target parts P to the arrival points of the liquids L1, L2, L3... Ln by applying the liquids are the flow-down distances X1, X2, X3. Therefore, the quality of the porous material can also be determined based on the flow-down distances X1, X2, X3.

  Next, the quality evaluation method for the porous material will be described with reference to the flowchart shown in FIG.

  For example, imaging of the target portion M on the surface of the porous material P is started using an imaging device such as a digital video camera. The surface of the porous material P is processed (step S11). That is, the surface of the porous material P is removed, and simple polishing, moisture adjustment, and marking are performed on the surface so as to be smooth as necessary. Subsequently, the target part M is measured for the surface color, and the initial (time zero) surface color is acquired (step S12).

  Next, as shown in FIG. 2A, the liquid is sprayed onto the measurement site M using the spraying device 21 (step S13). As shown in FIG. 5B, a part of the liquid is absorbed by the surface of the porous material P, and the remaining liquid flows down from the target portion M.

  Next, as shown in FIG. 3C, the color of the surface of the target portion M is measured using the color measuring device 11, and the measurement of the change with time is started (step S14). Furthermore, the flow-down distance from the target part M of the liquid L1 is measured using the length measuring instrument 12 (step S15).

  It is determined whether or not to repeat the color measurement and the flow-down distance measurement (step S16). When the measurement is repeated (YES in step S16), the process proceeds to step S13. When the measurement is repeated, a liquid is applied to the target part M (step S13). The surface color of the target region M is measured using a colorimeter (step S14), and the flow distances X2... Xn of the liquids L2.

  On the other hand, when the measurement is not repeated (NO in step S16), the process proceeds to step S17.

In step S17, the quality determination device 13 determines the maximum color difference measurement time T _L , the surface color restoration speed maximum value V _H , and the flow-down distance X1. Here, as shown in FIG. 5, the “maximum color difference measurement time T _L ” is the elapsed time from the application of the liquid to the maximum color difference. The “surface color restoration speed maximum value V _H ” is the maximum value of the color difference restoration amount per unit time in the process of restoring the surface color from the maximum color difference. The “flow distance” is the distances X1... Xn that the liquids L1... Ln flow down from the target site M to which the porous material P is applied as shown in FIG.

The quality determination device 13 determines the quality of the porous material P based on the maximum color difference measurement time T _L , the surface color restoration speed maximum value V _H , the flow-down distance X1... Xn, and the output device 16 outputs these results. Is displayed.

  According to the above embodiment, since no sample collection is required, the inspection method is “by non-destructive” or “can be performed on the actual structure in the field”.

  In any case, by using a battery-powered device, a power supply device or the like is unnecessary, and no special consideration is required for performing the inspection. There is no need for a power supply or a large work space, such as air permeability test, water permeability / water absorption test, etc.

  The time required for the measurement including the preparation of the equipment is a “simple in a short time” method of several minutes to several tens of minutes, and does not require a long time like an air permeability test, a water permeability / water absorption test and the like.

  Since it does not use measuring equipment that requires specialized knowledge for handling, it is possible to carry out "anyone" and "easy" work.

  The effect of cracks that are always present in the structure is excessive in the measurement by air permeability test and water permeability / water absorption test, but this method also visualizes the effect of cracks. It becomes possible and is hardly affected by cracks.

  There are advantages as described above, and according to the present invention, it is possible to evaluate the concrete of the actual structure quickly, easily, without being affected by cracks and the like without causing damage.

  In particular, there is a feature that “it can be repeatedly performed”, and the fact that information such as characteristic values reflecting the quality difference of concrete can be further obtained is an advantage that other methods do not have. Further, the quality of the porous material can be clearly distinguished by repeating the application of the identification material a plurality of times.

  Furthermore, the quality of the porous material can be accurately evaluated by evaluating the flow distance.

  In addition, this invention is not limited to this embodiment, Moreover, each embodiment can be changed and corrected in the range which does not change the meaning of invention.

  Experiments were conducted to evaluate the quality of porous materials using changes in surface color over time. The surface color change characteristics when pure water was sprayed on the surface of various quality concrete were investigated.

(1) Test body The test body used the concrete of 100x100x400mm from which water-cement ratio differs. It is demolded on the 1st and 7th days from the placement of concrete, and the surface quality is differentiated according to the initial curing conditions up to the age of 28 days in the test room. Ordinary Portland cement was used as the cement. Measurement was performed about one year after the preparation of the test specimen. The test specimen was dried in the air by installing the test specimen in a test chamber where the temperature and humidity were controlled after completion of the initial curing for 28 days.

(2) Measuring method As shown in FIG. 2, pure water was sprayed on the surface of the test body using a spray device. The amount of water sprayed on the specimen was about 0.1 μl / mm ² per water spray.

  At the time of measurement, the color measuring device was installed vertically downward, and the 100 × 400 mm side surface of the test body was used as the surface to be measured. The colorimetric device 11 measured changes in surface color over time at four locations on one side at intervals of 5 seconds for a maximum of 180 seconds.

(3) Measurement result The graph of FIG. 5 shows the measurement example of the time-dependent change of the color difference of the concrete surface. As the color system, L ^* a ^* b ^* color system was used. The color difference is the amount of change in the surface color from the initial value, and the initial value here is the concrete surface color before water application. The color change with time increases rapidly immediately after the application of water, and decreases after reaching the maximum value of the color difference. In the figure, the position P2 where data is plotted on the time-dependent change curve is the maximum value of the color difference in the curve, and is the time when the maximum color difference at the relevant location is measured. That is, the plot position indicates a state where the surface color of the concrete is darkened most by watering. The elapsed time after watering corresponding to this maximum color difference is defined as the maximum color difference measurement time T _L. In this example, the maximum color difference measurement time is 100 seconds. In the process in which the change in surface color over time is restored from the maximum color difference, the largest (maximum gradient) of the surface color restoration amount per unit time is set as the surface color restoration speed maximum value V _H. From the above, in the present invention, the maximum color difference measurement time T _L and the surface color restoration speed maximum value V _H are obtained as evaluation values representing the characteristics of the surface color change.

The graph of FIG. 6 shows the relationship between the maximum color difference measurement time T _L and the surface color restoration speed maximum value V _H and the water absorption characteristics of concrete. The water absorption characteristics of the concrete were calculated by dividing the weight of water absorbed when the concrete specimen was immersed in water for 4 hours by the surface area of the specimen. According to the figure, as the amount of water absorption increases, the maximum color difference measurement time T _L tends to decrease, and the surface color restoration speed maximum value V _H tends to increase. As an index for evaluating the high resistance to water absorption, the maximum color difference measurement time T _L has a positive correlation, and the surface color restoration speed maximum value V _H has a negative correlation.

That is, it is understood that the concrete is dense and high quality as the maximum color difference measurement time _TL increases. Further, it is understood that the concrete is poor, that is, has a low quality as the surface color restoration speed maximum value V _H increases.

The graph of FIG. 7 shows the relationship between the maximum color difference measurement time T _L and the surface color restoration speed maximum value V _H and the curing conditions of the concrete.

In one measurement of water spray, various types of concrete were evaluated using the maximum color difference measurement time _TL and the maximum surface color restoration speed V _H , and in particular, it was confirmed that relatively low quality concrete could not be evaluated accurately. It was done.

That is, FIG. 3A shows the test result of concrete having a water cement ratio of 40%, which is a condition of relatively high quality. The curing conditions were three stages: excellent ○, good Δ, and good ×. As the curing conditions were improved, the maximum color difference measurement time T _L was increased, and the surface color restoration speed maximum value V _H was decreased. Therefore, the evaluation corresponding to the quality was possible by the evaluation value obtained in the present invention. On the other hand, as shown in FIG. 5B, when the water cement ratio is 60%, which is a concrete with relatively low quality, the maximum surface color restoration speed V _H was measured almost immediately after watering. There was no clear difference between good and bad. In addition, the maximum color difference measurement time _TL was large for a specimen with good curing, and did not correspond to the high surface quality assumed from the curing conditions.

Then, the effect of the measurement was verified by repeating watering on concrete. FIG. 8 shows a measurement example of the change over time of the surface color during repeated watering. As shown in FIG. 3A, the time-dependent change curve of high-quality concrete has been remarkably slowed after the second watering. On the other hand, as shown in FIG. 5B, the time-dependent change curve of low-quality concrete gradually changes greatly by repeating watering. That is, by repeating water spraying, the maximum color difference measurement time _TL decreases and the surface color restoration speed maximum value _VH increases. That is, even in low-quality concrete, it was confirmed that the maximum color difference measurement time T _L and the surface color restoration speed maximum value V _H become prominent by increasing the number of water sprays.

FIG. 9 shows the relationship between the maximum color difference measurement time T _L and the surface color restoration speed maximum value V _H and the curing conditions in concrete having a water cement ratio of 60%, which is a relatively low quality condition. The number of watering was repeated 3 times. According to the figure, as the curing condition is improved, the maximum color difference measurement time T _L is increased and the surface color restoration speed maximum value V _H is decreased, which corresponds to the surface layer quality assumed from the curing condition. It was. From the above, it has been clarified that the evaluation can be accurately performed by repeatedly watering a plurality of times with respect to the variation in evaluation at the time of one watering shown in FIG.

  The concrete quality evaluation by repeated watering was further verified.

(1) Measuring object The measuring object is a medium-sized ramen viaduct test specimen constructed and exposed in an outdoor environment. Examination was carried out using four columns (hereinafter referred to as column test bodies) that were differentiated in quality among the columns of this ramen viaduct test body. Each of the column test bodies has a rectangular cross section of 300 × 400 mm, the height of the ground part is 2,350 mm, and a slab is constructed on the upper part. Ready-mixed concrete was used for the preparation of the test body, and pumping, driving, and vibration compaction were performed according to standard construction procedures. Measurement was carried out about two years after the construction. Table 1 shows an outline of the column specimen.

(2) Measuring method The measuring surface was the inner surface of the viaduct that avoided the influence of rainfall. The measurement position was about 1,000 mm above the ground, near the center of the 400 mm wide surface, and the number of measurement points for each column specimen was one. Watering was performed by repeating 0.25 ml of water in a circle having a diameter of 60 mm 10 times at intervals of 2 minutes.

(3) Measurement results FIG. 10 shows a comparison of the measurement results of the low-quality test specimen S3 (FIG. (A)) and the high-quality test specimen S1 (FIG. (B)) as an example of the color difference with time. Show. As the color system, L ^* a ^* b ^* color system was used. The color difference has an initial value of 0, and increases rapidly with watering. Moisture imparted by watering gradually disappears from the surface over time due to diffusion inside or evaporation from the surface. Since the main factor that changes the color difference in this method is the presence of moisture, the color difference after watering corresponds to the state of disappearance of moisture on the surface and is restored to the initial value over time. On the other hand, the color difference is further increased by repeating the water spraying, but the color difference reaches its peak with the increase in the number of repetitions, and the change per time is slowed down. These are thought to be behaviors that capture the saturation of the water content in the surface layer.

As is apparent from comparison between the test body S3 and the test body S1 in FIGS. 10A and 10B, the surface color change characteristics during repeated watering vary greatly depending on the quality of the concrete. Here, attention is focused on the surface color restoration speed maximum value V _H as an index related to the surface color change. As shown in FIG. 6, the surface color restoration speed maximum value V _H has a correlation with the water absorption resistance, and the surface water color restoration speed maximum value V _H becomes small in the concrete having high water absorption resistance.

FIG. 11 shows the relationship between the number of sprinkling repetitions and the maximum surface color restoration speed V _H of the column specimen. The surface color restoration speed maximum value V _H decreased with repeated watering, and in the high-quality specimen S1, V _H became almost zero after 2 to 4 water sprays. On the other hand, in the lowest quality specimen S5 that has been inappropriately hydrated as a material defect, and in the low quality specimen S3 that has been removed from the mold at an early stage, V _H asymptotically approaches 0, It did not converge after 10 water sprays.

From the above, the number of water sprays required for convergence of the surface color restoration speed maximum value V _H obtained in the present invention (surface color restoration speed maximum value convergence number) can be used as an evaluation index. Moreover, in the result shown here, the result was obtained that the surface color restoration speed maximum value V _H is smaller as the quality of the concrete is higher, regardless of the number of times of watering. On the other hand, as shown in FIG. 7, depending on the situation, it is considered that there is a possibility that the evaluation may be mistaken for the maximum surface color restoration speed value V _{H for the} first watering. However, it is necessary to evaluate the surface color restoration speed maximum value V _H and to converge the surface color restoration speed maximum value V _H when the water spray is repeated a plurality of times, which is a feature of the present invention. It is possible to evaluate the quality by combining the number of watering, etc., and it is considered that appropriate evaluation can be performed.

  In addition, we investigated the flow distance from the target site of water.

  As shown in FIG. 12, it can be seen that the water flow distance increases as the quality of the high-quality concrete increases after the number of watering repetitions of 3 or more. The flow-down distance is considered to have a certain degree of relationship with the amount of excess water that is not instantaneously absorbed, that is, the high water absorption resistance. In particular, it was confirmed that the flow-down distance when watering repeatedly reflects the quality difference of concrete. A simple evaluation relating to the quality of concrete can be performed based on the flow distance during repeated watering obtained in the present invention.

DESCRIPTION OF SYMBOLS 10 Porous material quality evaluation apparatus 11 Color measurement apparatus 12 Length measurement apparatus 13 Quality determination apparatus 14 Storage apparatus 15 Input apparatus 16 Output apparatus L Identification material (liquid)
P Porous material M Target site

Claims (3)

An identification material is applied to the surface of the target portion of the porous material,
Measure the change over time of the surface color of the porous material provided with the identification material,
Repeating the application of the identification material and measuring the change over time multiple times,
Maximum color difference measurement time as the elapsed time from the application of the first identification material to the maximum color difference, or the maximum surface color restoration speed as the maximum value of color difference change per unit time after the maximum color difference measurement time Decide
A quality evaluation method for a porous material, wherein the quality of the porous material is determined based on the maximum color difference measurement time or the maximum value of the surface color restoration speed. The identification material is a liquid,
Every time the identification material is applied, the flow distance from the target portion of the liquid is measured,
Determine the quality of the porous material based on the flow-down distance
The quality evaluation method of the porous material of Claim 1. The quality of the porous material is determined based on the maximum color difference measurement time, the surface color restoration speed maximum value, or the number of repetitions until the flow-down distance reaches a predetermined value.
The quality evaluation method of the porous material of Claim 2.