JP2003279562A - Method and apparatus for measuring surface water in sands - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for measuring percentage of surface moisture in sands, which can accurately and rapidly measure a rate of the surface moisture in the sand relating to its specific gravity and fineness modulus. <P>SOLUTION: Reference sands having different weight, fineness modulus and the like are sampled respectively and carried out a surface drying, and spaces in an apparent volume of the surface dried sands are replaced by water in such a condition that the fineness modulus is kept constant. The weight of the water is measured as a saturation volume of water, thereby obtaining rates of saturation water as data of each reference sample and storing/ managing the data. Then, in order to obtain a correction volume of water for sands to be used, an execution sample is taken in which the rate of surface water is made even, spaces in an apparent volume of the surface water sands are replaced by water, and the weight of the water is measured as a saturation volume of water absorption, thereby obtaining a saturation rate of water absorption of the execution sample. Next, the saturation rate of water absorption of the execution sample is subtracted from the rate of saturation water of the reference sample having the weight, fineness modulus and the like equal to the execution sample, and thereby calculating the rate of the surface water in the sands to be used. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to know the amount of surface water contained in sand in advance in order to obtain an appropriate amount of water mixed in sand (corrected water amount) in the production of ready-mixed concrete or the like. The present invention relates to a method and apparatus for measuring surface water of sand.

[0002]

2. Description of the Related Art Ready-mixed concrete consists of cement, water, sand,
It is used in a state where gravel, etc. is kneaded at an appropriate ratio,
According to the construction mode and material characteristics, etc., the "unit water amount" that is the appropriate water mixing ratio has been determined, and the amount of water supplied to obtain the unit water amount is called the "corrected water amount". Since the amount of water is a value obtained by subtracting the amount of surface water contained in sand from the unit amount of water in advance, it is necessary to properly know the amount of surface water in advance in order to ensure accuracy in the corrected amount of water. The amount of surface water is calculated by multiplying the weight of the sample sand by the surface water rate.

However, it is said that it is difficult to measure the surface water content of wet sand. It seems that the reason is that the measured values are not stable depending on the conditions if checked carefully. It is natural for natural products to use natural sand, and no matter how many manual steps are taken, the values will vary. Although there are individual differences in the measurement, it is considered that this is because the coarse grain ratio changes and the surface area changes because of fluctuations in quality and specific gravity and unstable particle size distribution. It is the voice of the person who engages in this because it cannot be relied on that the surface water rate changes each time the conditions change. It is no exaggeration to say that there is no one thing in the world. Conventionally, for this reason, the surface water rate is set evaluatively by comparing with standards, standards, samples, templates, etc., and the error currently depends on a slump test that takes time and labor. is there.

There are many causes of measurement error, but the important factors are as follows when looking at the quality of sand even if the weight is the same. a) The specific gravity changes when the weight is light and heavy, so the surface water volume changes when the production area and water system change. b) If the particle size distribution is different, the surface area is changed, and accordingly, if the coarse particle ratio is changed, the surface water amount is changed. As long as there is no guarantee that it is constantly stable, it is a minimum essential check item, and simplification of either will cause an error in the measured value. News reports such as newspapers often mention that the method for measuring the surface water ratio of sand has not been established, but it can also be seen as important. For example, the measurement error is ±
It is set to about 2%, but if so, the unit water volume would be 185
To adjust the slump 1 cm in kg, 1.
2%, therefore the amount of water is 2.22 kg, and the surface water ratio is 0.277% when viewed from the unit sand amount. Moreover, if the allowable range of slump is ± 2 cm, it is 0.55% from the surface water ratio,
Considering slump as the standard, the allowable measurement error is 0.5% or less, which suggests that it is necessary to review the current measurement method.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, the present invention provides a method for measuring the surface water of sand, which can accurately and quickly measure the surface water rate related to the specific gravity of sand and the coarse particle ratio. An object is to provide a measuring device.

[0006]

In order to achieve the above object, the present invention is to dry the surface of sand sampled in a standard manner every time the weight, the coarse particle ratio, etc. are different, to make the coarse particle ratio constant. By replacing the voids in the apparent volume of the sand in the surface of the lever with water, and measuring the weight of the water as the amount of saturated water, the saturated water rate was obtained as data for each reference sample and stored and managed, To know the corrected water volume for the sand used,
Saturated water absorption of the run sample was obtained by collecting the run sample with equalized surface water ratio, replacing the voids in the apparent volume of this surface water sand with water, and measuring the weight of the water as the saturated water absorption. Then, the saturated water absorption rate of the execution sample is subtracted from the saturated water rate of the reference sample in which the execution sample has the same weight, coarse grain ratio, etc., and the surface water rate of the used sand is calculated. A method for measuring surface water of sand is provided.

According to the above structure, when the saturated water absorption rate of the execution sample is subtracted from the saturated water rate of the reference sample, the value is the surface water rate of the used sand. Therefore, this surface water rate is added to the weight of the used sand. By multiplying, the amount of surface water is obtained, and the corrected amount of water added to the sand can be obtained based on this.

Further, according to the present invention, a container having an opening capable of supplying / draining sample sand, a water tank for soaking the sample sand together with the container having an opening capable of supplying / draining water, and a water tank receiver with a vibrator can be moved up and down. A water tank,
It consists of an electronic scale on which a container having the above-mentioned water supply / drainage opening is placed, and a water-absorbing cushion for receiving the above-mentioned container having the above-mentioned water supply / drainage opening is provided at the bottom of the water tank, and water supply and drainage to / from the water tank of the water tank are performed. It is intended to provide a surface water measuring device for sand, which is characterized by being moved up and down.

According to the above construction, the vibration of the vibrator promotes and equalizes the permeation of water during the submersion of the container having the opening through which water can be supplied and drained, and the water is saturated after the submersion of water. Is promoted. In addition, since excess water is absorbed by the water-absorbent cushion for weighing attached to a container having an opening through which water can be supplied and drained, accurate tare weight reduces weighing errors. Further, since water supply and drainage to and from the water tank depend on the upper and lower sides of the water supply tank, the structure is simplified and the water supply and drainage time is shortened.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, when sand is put in a container having an opening through which water can be supplied and drained, and then the container is pulled up into the container and water drops do not fall, that is, the adhesive force due to only surface tension is applied. The state of resisting the gravity of water is defined as "saturated state". However, the density of sand is unstable,
Therefore, the drainage is poor, and the saturated state is promoted by operating the vibrator for defoaming. The saturated water amount means the amount of water absorbed until reaching a saturated state, which is the amount of water obtained by replacing the voids in the apparent volume of sand with water.

Since it is assumed that the saturated water content is measured, according to the present invention, the surface water ratio of the sand sample is only 40%.
Since it is measured in seconds and can be used for quality control, it can be said to be an epoch-making measurement method. Considering the origin of the term surface water of sand, it is considered to indicate the surface wet state of one grain of sand. However, the reality is the amount of water in the voids of the sand. It is well known that the voids change depending on the apparent volume density. From this point of view, the saturated state is considered, and the saturated water state of sand is used based on specific gravity and coarse particle ratio to measure the amount of saturated water sand, and the calculation is expanded to a surface water rate measuring method.

It has been confirmed by experiments that the saturated water ratio is almost constant if the coarse particle ratio is constant. About this, the surface water ratio of sand is artificially set to 0 to 10%, and the saturated water ratio sample-treated is shown in the table.

[0013]

[Table 1]

According to the present invention, the saturated water rate absorbed in the surface dry state is determined for a reference sample which is divided stepwise from the specific gravity and the coarse particle rate (Table 2-1 and Table 3-1), and it is used as data. It is stored and managed (the average value of the saturated water ratio is 22.03, 21.49 respectively), and when the corrected water amount is calculated for the actual sand used, the sand of the execution sample reaches the saturated state in the surface water sand as it is. The saturated water absorption amount and the saturated water absorption that are absorbed up to the above are calculated (Table 2-2, Table 3-2), and the surface water ratio (10) of the used sand is calculated as the saturated water ratio. The error (12) is the error of the surface water rate in the Chapman method. In addition, Table 2 uses sand of the Jinzu River system of Toyama Prefecture, and Table 3 uses sand of the Shogawa River system of the same prefecture.

[0015]

[Table 2-1]

[0016]

[Table 2-2]

[0017]

[Table 3-1]

[0018]

[Table 3-2]

The saturated water ratio changes if either the specific gravity or the coarse grain ratio fluctuates. However, the saturated water ratios cancel each other out depending on the fluctuation ratio, and within the normal coarse grain ratio range of the ready-mixed concrete, the measurement error ±
Passing 0.5% or less easily.

[0020]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a perspective view showing a measuring device of the present invention, which is a representative example of a water tank 1, a water tank receiver 3 with a vibrator 4, and a "container having an opening capable of supplying and draining water". A net container 5 with a collar, a part of which is a net 6, and a flange 8 at the upper end, a water supply tank 7 for the water tank 1, an electronic scale 9 for measuring the weight of sand in the net container 5 with a collar, the measurement result and It is composed of a CPU printer 11 which outputs a calculation result. This measuring device is used for both measurement of the reference sample and the execution sample.

Regarding the water supply tank 7, 13 is a vertical drive cylinder, and 14 is a flexible tube made of rubber, which raises the water supply tank 7 to supply water to the water tank 1, and lowers it to drain water. In addition, a drain groove 16 is provided around the bottom of the water tank receiver 3,
A water absorbing cushion 15 is arranged along the inner side of 6.
By receiving the water tank 1 with the water absorbing cushion 15, not only the vibration of the vibrator 4 can be efficiently applied to the water tank 1, but also the absorption and drainage of water attached to the mesh container 5 with a collar at the time of drainage are promoted. . Further, the water tank receiver 3 is provided with a timer 17 for setting the operating time of the vibrator 4. First, the procedure for measuring the saturated water ratio will be described.

(Measurement of the amount of saturated water and sand) JIS A1102 (reference sample) or A111
Based on 1-3 (execution sample), the classified sand is weighed to a sample amount (for example, 400 g) according to the measured coarse particle ratio, using the sieved sand. The value is set to Ms for the execution sample and M for the reference sample. In the case of the reference sample, in order to prevent the deviation of the coarse particle ratio, the surface water ratio is arbitrarily set, and the sample is well blended in order to average the surface water ratio. The sample is placed in the mesh container 5 with a collar. Put the net container 5 with a collar in the water tank 1 and operate the vibrator 4 while immersing the sand in the water. As a result, the density becomes stable, drainage is improved, and air is removed. The water in the water tank 1 is drained by lowering the water supply tank 7. Further, the water adhering to the flanged net container 5 is absorbed by the water absorbing cushion 15. The net container 5 with a collar is pulled up, placed on the electronic scale 9, and the weight of saturated water and sand is measured. This value is M in the reference sample
1, Ms1 in the execution sample.

Obtaining the sample sand weights M and Ms and the saturated water sand weights M1 and Ms1 in this way, the calculation of the saturated water ratio is as follows.

(Saturated water rate of reference sample) A) Saturated water amount = M1−M B) Saturated water rate = A ÷ M × 100 (Saturated water rate measurement of data, 5 points or more) C) Reference saturated water rate = B (Lower limit value + upper limit value) / 2 That is, the saturated water rate (B) of the reference sample = (M1-M)
÷ M × 100 (saturated water absorption rate of execution sample) Similarly, for each execution sample, F) Saturated water absorption amount = Ms1−Ms G) Saturated water absorption rate = (Ms1−Ms) ÷ Ms × 100

From the above, the saturated water rate of the reference sample (stored as data) and the saturated water absorption rate of the execution sample (calculated for the sand used each time) were obtained, and thus the corrected water amount was obtained for the sand used. Therefore, the presumed surface water rate is calculated as follows. H) Approximate surface water rate of the run sample = Saturated water rate of the reference sample C-Saturated water absorption rate of the run sample G Also, this is the estimated surface water rate (H) = C- (Ms1-M
s) ÷ Ms × 100. (Ms1-Ms)
÷ Ms × 100 part is a measurement and calculation item when actually manufacturing ready-mixed concrete.

Therefore, regarding the used sand, the surface water amount = the weight of the used sand × the surface water ratio (H), the corrected water amount = the unit water amount of the used sand-the surface water amount, and this corrected water amount is mixed into the sand at the site.

Next, supplementary points and caution points will be described. a) Measure H at 5 points or more at regular intervals b) Standard surface water ratio = sum of 5 points / 5 c) Actual sand amount = Ms− (Ms × b / 100) d) Saturated water amount = Ms1-c e) Saturated water rate = d ÷ c × 100 f) Measurement point saturated water rate difference = e-C

Saturated water ratio (e) = (Ms1−Ms (Ms ×
b / 100)) ÷ (Ms− (Ms × b))

I) Error correction value = f × (H ÷ e) Increase (−) Decrease (+) J) Surface water rate = H ± I * Error correction value is the difference in saturated water rate due to fluctuations in the coarse grain ratio. To the ratio of surface water ratio. When the value of the coarse particle ratio becomes large, the particle size becomes coarse (small surface area) and the saturated water ratio decreases. When the value becomes small, the particle size becomes fine (large surface area) and the saturated water ratio increases. Therefore, the surface water ratio is corrected accordingly.

[Brief description of drawings]

FIG. 1 is a perspective view showing a sand surface water measuring device of the present invention.

[Explanation of symbols]

1 aquarium 3 water tank receiver 5 Net container with a collar 7 water tank 9 Electronic scale 15 Water-absorbent cushion

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 24, 2002 (2002.6.2)
4)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Method and apparatus for measuring surface water of sand

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to know the amount of surface water contained in sand in advance in order to obtain an appropriate amount of water mixed in sand (corrected water amount) in the production of ready-mixed concrete or the like. The present invention relates to a method and apparatus for measuring surface water of sand.

[0002]

2. Description of the Related Art Ready-mixed concrete consists of cement, water, sand,
It is used in a state where gravel, etc. is kneaded at an appropriate ratio,
According to the construction mode and material characteristics, etc., the "unit water amount" that is the appropriate water mixing ratio has been determined, and the amount of water supplied to obtain the unit water amount is called the "corrected water amount". Since the amount of water is a value obtained by subtracting the amount of surface water contained in sand from the unit amount of water in advance, it is necessary to properly know the amount of surface water in advance in order to ensure accuracy in the corrected amount of water. The amount of surface water is calculated by multiplying the weight of the sample sand by the surface water rate.

However, it is said that it is difficult to measure the surface water content of wet sand. It seems that the reason is that the measured values are not stable depending on the conditions if checked carefully. It is natural for natural products to use natural sand, and no matter how many manual steps are taken, the values will vary. Although there are individual differences in the measurement, it is considered that this is because the coarse grain ratio changes and the surface area changes because of fluctuations in quality and specific gravity and unstable particle size distribution. It is the voice of the person who engages in this because it cannot be relied on that the surface water rate changes each time the conditions change. It is no exaggeration to say that there is no one thing in the world. Conventionally, for this reason, the surface water rate is set evaluatively by comparing with standards, standards, samples, templates, etc., and the error currently depends on a slump test that takes time and labor. is there. Note that the coarse particle ratio is the value of the sample retained on each sieve.
The sum of mass percentages is calculated and the value is divided by 100.
(If the coarse grain ratio changes by 0.2, the composition will be changed.
It is used for such treatment).

There are many causes of measurement error, but the important factors are as follows when looking at the quality of sand even if the weight is the same. a) The specific gravity changes when the weight is light and heavy, so the surface water volume changes when the production area and water system change. b) If the particle size distribution is different, the surface area is changed, and accordingly, if the coarse particle ratio is changed, the surface water amount is changed. As long as there is no guarantee that it is constantly stable, it is a minimum essential check item, and simplification of either will cause an error in the measured value. News reports such as newspapers often mention that the method for measuring the surface water ratio of sand has not been established, but it can also be seen as important. For example, the measurement error is ±
It is set to about 2%, but if so, the unit water volume would be 185
To adjust the slump 1 cm in kg, 1.
2%, therefore the amount of water is 2.22 kg, and the surface water ratio is 0.277% when viewed from the unit sand amount. Moreover, if the allowable range of slump is ± 2 cm, it is 0.55% from the surface water ratio,
Considering slump as the standard, the allowable measurement error is 0.5% or less, which suggests that it is necessary to review the current measurement method.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, the present invention provides a method for measuring the surface water of sand, which can accurately and quickly measure the surface water rate related to the specific gravity of sand and the coarse particle ratio. An object is to provide a measuring device.

[0006]

In order to achieve the above object, the present invention is to dry the surface of sand sampled in a standard manner every time the weight, the coarse particle ratio, etc. are different, to make the coarse particle ratio constant. By replacing the voids in the apparent volume of the sand in the surface of the lever with water, and measuring the weight of the water as the amount of saturated water, the saturated water rate was obtained as data for each reference sample and stored and managed, To know the corrected water volume for the sand used,
Saturated water absorption of the run sample was obtained by collecting the run sample with equalized surface water ratio, replacing the voids in the apparent volume of this surface water sand with water, and measuring the weight of the water as the saturated water absorption. Then, the saturated water absorption rate of the execution sample is subtracted from the saturated water rate of the reference sample in which the execution sample has the same weight, coarse grain ratio, etc., and the surface water rate of the used sand is calculated. A method for measuring surface water of sand is provided.

According to the above structure, when the saturated water absorption rate of the execution sample is subtracted from the saturated water rate of the reference sample, the value is the surface water rate of the used sand. Therefore, this surface water rate is added to the weight of the used sand. By multiplying, the amount of surface water is obtained, and the corrected amount of water added to the sand can be obtained based on this.

Further, according to the present invention, a container having an opening capable of supplying / draining sample sand, a water tank for soaking the sample sand together with the container having an opening capable of supplying / draining water, and a water tank receiver with a vibrator can be moved up and down. A water tank,
It consists of an electronic scale on which a container having the above-mentioned water supply / drainage opening is placed, and a water-absorbing cushion for receiving the above-mentioned container having the above-mentioned water supply / drainage opening is provided at the bottom of the water tank, and water supply and drainage to / from the water tank of the water tank are performed. It is intended to provide a surface water measuring device for sand, which is characterized by being moved up and down.

According to the above construction, the vibration of the vibrator promotes and equalizes the permeation of water during the submersion of the container having the opening through which water can be supplied and drained, and the water is saturated after the submersion of water. Is promoted. In addition, since excess water is absorbed by the water-absorbent cushion for weighing attached to a container having an opening through which water can be supplied and drained, accurate tare weight reduces weighing errors. Further, since water supply and drainage to and from the water tank depend on the upper and lower sides of the water supply tank, the structure is simplified and the water supply and drainage time is shortened.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, when sand is put in a container having an opening through which water can be supplied and drained, and then the container is pulled up into the container and water drops do not fall, that is, the adhesive force due to only surface tension is applied. The state of resisting the gravity of water is defined as "saturated state". However, the density of sand is unstable,
Therefore, the drainage is poor, and the saturated state is promoted by operating the vibrator for defoaming. The saturated water amount means the amount of water absorbed until reaching a saturated state, which is the amount of water obtained by replacing the voids in the apparent volume of sand with water.

Since it is assumed that the saturated water content is measured, according to the present invention, the surface water ratio of the sand sample is only 40%.
Since it is measured in seconds and can be used for quality control, it can be said to be an epoch-making measurement method. Considering the origin of the term surface water of sand, it is considered to indicate the surface wet state of one grain of sand. However, the reality is the amount of water in the voids of the sand. It is well known that the voids change depending on the apparent volume density. From this point of view, the saturated state is considered, and the saturated water state of sand is used based on specific gravity and coarse particle ratio to measure the amount of saturated water sand, and the calculation is expanded to a surface water rate measuring method.

It has been confirmed by experiments that the saturated water ratio is almost constant if the coarse particle ratio is constant. About this, the surface water ratio of sand is artificially set to 0 to 10%, and the saturated water ratio sample-treated is shown in the table.

[0013]

[Table 1]

According to the present invention, the saturated water rate absorbed in the surface dry state is determined for a reference sample which is divided stepwise from the specific gravity and the coarse particle rate (Table 2-1 and Table 3-1), and it is used as data. It is stored and managed (the average value of the saturated water ratio is 22.03, 21.49 respectively), and when the corrected water amount is calculated for the actual sand used, the sand of the execution sample reaches the saturated state in the surface water sand as it is. The saturated water absorption amount and the saturated water absorption that are absorbed up to the above are calculated (Table 2-2, Table 3-2), and the surface water ratio (10) of the used sand is calculated as the saturated water ratio. The error (12) is the error of the surface water rate in the Chapman method. In addition, Table 2 uses sand of the Jinzu River system of Toyama Prefecture, and Table 3 uses sand of the Shogawa River system of the same prefecture.

[0015]

[Table 2-1]

[0016]

[Table 2-2]

[0017]

[Table 3-1]

[0018]

[Table 3-2]

The saturated water ratio changes if either the specific gravity or the coarse grain ratio fluctuates. However, the saturated water ratios cancel each other out depending on the fluctuation ratio, and within the normal coarse grain ratio range of the ready-mixed concrete, the measurement error ±
Passing 0.5% or less easily.

[0020]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a perspective view showing a measuring device of the present invention, which is a representative example of a water tank 1, a water tank receiver 3 with a vibrator 4, and a "container having an opening capable of supplying and draining water". A net container 5 with a collar, a part of which is a net 6, and a flange 8 at the upper end, a water supply tank 7 for the water tank 1, an electronic scale 9 for measuring the weight of sand in the net container 5 with a collar, the measurement result and It is composed of a CPU printer 11 which outputs a calculation result. This measuring device is used for both measurement of the reference sample and the execution sample.

Regarding the water supply tank 7, 13 is a vertical drive cylinder, and 14 is a flexible tube made of rubber, which raises the water supply tank 7 to supply water to the water tank 1, and lowers it to drain water. In addition, a drain groove 16 is provided around the bottom of the water tank receiver 3,
A water absorbing cushion 15 is arranged along the inner side of 6.
By receiving the water tank 1 with the water absorbing cushion 15, not only the vibration of the vibrator 4 can be efficiently applied to the water tank 1, but also the absorption and drainage of water attached to the mesh container 5 with a collar at the time of drainage are promoted. . Further, the water tank receiver 3 is provided with a timer 17 for setting the operating time of the vibrator 4. First, the procedure for measuring the saturated water ratio will be described.

(Measurement of the amount of saturated water and sand) JIS A1102 (reference sample) or A111
Based on 1-3 (execution sample), the classified sand is weighed to a sample amount (for example, 400 g) according to the measured coarse particle ratio, using the sieved sand. The value is set to Ms for the execution sample and M for the reference sample. In the case of the reference sample, in order to prevent the deviation of the coarse particle ratio, the surface water ratio is arbitrarily set, and the sample is well blended in order to average the surface water ratio. The sample is placed in the mesh container 5 with a collar. Put the net container 5 with a collar in the water tank 1 and operate the vibrator 4 while immersing the sand in the water. As a result, the density becomes stable, drainage is improved, and air is removed. The water in the water tank 1 is drained by lowering the water supply tank 7. Further, the water adhering to the flanged net container 5 is absorbed by the water absorbing cushion 15. The net container 5 with a collar is pulled up, placed on the electronic scale 9, and the weight of saturated water and sand is measured. This value is M in the reference sample
1, Ms1 in the execution sample.

Obtaining the sample sand weights M and Ms and the saturated water sand weights M1 and Ms1 in this way, the calculation of the saturated water ratio is as follows.

(Saturated water rate of reference sample) A) Saturated water amount = M1−M B) Saturated water rate = A ÷ M × 100 (Saturated water rate measurement of data, 5 points or more) C) Reference saturated water rate = B (Lower limit value + upper limit value) / 2 That is, the saturated water rate (B) of the reference sample = (M1-M)
÷ M × 100 (Saturated water absorption rate of execution sample) Similarly, for each execution sample, F) Saturated water absorption amount = Ms1−Ms G) Saturated water absorption rate = (Ms1−Ms) ÷ Ms × 100

From the above, the saturated water ratio (data
Stored as data) and saturated water absorption of the run sample
(Calculation of sand used each time) was obtained.
This is a prerequisite for obtaining the corrected amount of water for sand.
Surface water rate is calculated as follows. H) Estimated surface water ratio of the run sample =(Satiated reference sample
Water ratio C-Saturated water absorption ratio G of execution sample) / (1 + C /
100) Also, this isSurface water ratio (H) = {C- (Ms1-M
s) ÷ Ms × 100} ÷ (1 + C / 100)Represented as
Be done. (Ms1-Ms) ÷ Ms × 100 is actually
It is a matter of measurement and calculation when manufacturing ready-mixed concrete.

Therefore, regarding the used sand, the surface water amount = the weight of the used sand × the surface water ratio (H), the corrected water amount = the unit water amount of the used sand-the surface water amount, and this corrected water amount is mixed into the sand at the site.

Next,Management by measurement point surface water rate trend
Width settingAnd points to note. a) Measure H at 5 points or more at regular intervals b) Standard surface water ratio = sum of 5 points / 5From this standard surface water ratio, calculate the difference in each saturated water ratio of the measurement sample.
Put out. c)Amount of sand= Ms- (Msxb / 100) d) Saturated water amount = Ms1-c e) Saturated water rate = d ÷ c × 100 f) Measurement point saturated water rate difference = e-CUsing the standard saturated water rate as a reference line, trace the saturated water rate difference value at each measurement point.
The measurement error tolerance range is set to the upper and lower limits.
Set. If it falls off, check the surface dry water saturation rate (standard)
Change saturated water rate).

Saturated water ratio (e) = (Ms1−Ms (Ms ×
b / 100)) ÷ (Ms− (Ms × b))

Surface water measured at a standard (average) surface water ratio
Calculate the rate. Surface water rate = {e− (Ms1−Ms) × 100 / Ms} ÷
When the value of (1 + e / 100 ) coarse grain ratio becomes large, the grain size becomes coarse (small surface area).
If the saturated water ratio decreases and becomes smaller, the particle size becomes finer.
(Large surface area), saturated water rate increases. So look at the sand
If the surface area of the applied volume changes, the surface water rate also changes. Change
And destabilizing the slump is an unmistakable fact
is there. From the above, pay attention to the stability of coarse grain ratio and specific gravity.
This is very important.

[Brief description of drawings]

FIG. 1 is a perspective view showing a sand surface water measuring device of the present invention.

[Explanation of symbols] 1 water tank 3 water tank receiver 5 mesh container with collar 7 water tank 9 electronic scale 15 water absorbent cushion ───────────────────────── ────────────────────────────

[Procedure amendment]

[Submission date] July 1, 2002 (2002.7.1)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

From the above, the saturated water rate of the reference sample (stored as data) and the saturated water absorption rate of the execution sample (calculated for the sand used each time) were obtained, and thus the corrected water amount was obtained for the sand used. Therefore, the presumed surface water rate is calculated as follows. H) Surface water rate of execution sample = (saturated water rate C of reference sample−saturated water absorption rate G of execution sample) ÷ (1 + C / 10
0) Also, this is the surface water ratio (H) = {C- (Ms1-M
s) ÷ Ms × 100} ÷ (1 + C / 100). The portion of (Ms1−Ms) ÷ Ms × 100 is a measurement and calculation item when actual ready-mixed concrete is manufactured.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

Next, the setting of the control width based on the trend of the surface water ratio at the measuring point and the precautions will be described. a) H is measured at 5 or more points at regular intervals b) Reference surface water ratio = a Sum of 5 points / 5 The respective saturated water ratio difference of the measurement sample is calculated from this reference surface water ratio. c) Sand amount = Ms− (Ms × b / 100) d) Saturated water amount = Ms1-c e) Saturated water rate = d ÷ c × 100 f) Measuring point saturated water rate difference = e−C Reference saturated water rate On the reference line, make a trend graph of saturated water rate difference values at each measurement point, and set the upper and lower control limits of the measurement error allowable range. If it falls off, check the surface dry saturated water ratio (change the standard saturated water ratio).

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

Saturated water rate (e) = {Ms1- (Ms- (M
s × b / 100))} ÷ (Ms- (Ms × b)) ───────────────────────────────── ─────────────────────

[Procedure amendment]

[Submission date] July 15, 2002 (2002.7.1)
5)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to know the amount of surface water contained in sand in advance in order to obtain an appropriate amount of water mixed in sand (corrected water amount) in the production of ready-mixed concrete or the like. The present invention relates to a method and apparatus for measuring surface water of sand.

[0002]

2. Description of the Related Art Ready-mixed concrete consists of cement, water, sand,
It is used in a state where gravel, etc. is kneaded at an appropriate ratio,
According to the construction mode and material characteristics, etc., the "unit water amount" that is the appropriate water mixing ratio has been determined, and the amount of water supplied to obtain the unit water amount is called the "corrected water amount". Since the amount of water is a value obtained by subtracting the amount of surface water contained in sand from the unit amount of water in advance, it is necessary to properly know the amount of surface water in advance in order to ensure accuracy in the corrected amount of water. The amount of surface water is calculated by multiplying the weight of the sample sand by the surface water rate.

However, it is said that it is difficult to measure the surface water content of wet sand. It seems that the reason is that the measured values are not stable depending on the conditions if checked carefully. It is natural for natural products to use natural sand, and no matter how many manual steps are taken, the values will vary. Although there are individual differences in the measurement, it is considered that this is because the coarse grain ratio changes and the surface area changes because of fluctuations in quality and specific gravity and unstable particle size distribution. It is the voice of the person who engages in this because it cannot be relied on that the surface water rate changes each time the conditions change. It is no exaggeration to say that there is no one thing in the world. Conventionally, for this reason, the surface water rate is set evaluatively by comparing with standards, standards, samples, templates, etc., and the error currently depends on a slump test that takes time and labor. is there. The coarse grain ratio is a value obtained by calculating the sum of the mass percentages of the samples remaining on each sieve and dividing the sum by 100 (if the coarse grain ratio changes by 0.2, the composition is changed). Is used for the treatment of).

There are many causes of measurement error, but the important factors are as follows when looking at the quality of sand even if the weight is the same. a) The specific gravity changes when the weight is light and heavy, so the surface water volume changes when the production area and water system change. b) If the particle size distribution is different, the surface area is changed, and accordingly, if the coarse particle ratio is changed, the surface water amount is changed. As long as there is no guarantee that it is constantly stable, it is a minimum essential check item, and simplification of either will cause an error in the measured value. News reports such as newspapers often mention that the method for measuring the surface water ratio of sand has not been established, but it can also be seen as important. For example, the measurement error is ±
It is set to about 2%, but if so, the unit water volume would be 185
To adjust the slump 1 cm in kg, 1.
2%, therefore the amount of water is 2.22 kg, and the surface water ratio is 0.277% when viewed from the unit sand amount. Moreover, if the allowable range of slump is ± 2 cm, it is 0.55% from the surface water ratio,
Considering slump as the standard, the allowable measurement error is 0.5% or less, which suggests that it is necessary to review the current measurement method.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, the present invention provides a method for measuring the surface water of sand, which can accurately and quickly measure the surface water rate related to the specific gravity of sand and the coarse particle ratio. An object is to provide a measuring device.

[0006]

In order to achieve the above object, the present invention is to dry the surface of sand sampled in a standard manner every time the weight, the coarse particle ratio, etc. are different, to make the coarse particle ratio constant. By replacing the voids in the apparent volume of the sand in the surface of the lever with water, and measuring the weight of the water as the amount of saturated water, the saturated water rate was obtained as data for each reference sample and stored and managed, To know the corrected water volume for the sand used,
Saturated water absorption of the run sample was obtained by collecting the run sample with equalized surface water ratio, replacing the voids in the apparent volume of this surface water sand with water, and measuring the weight of the water as the saturated water absorption. Then, the saturated water absorption rate of the execution sample is subtracted from the saturated water rate of the reference sample in which the execution sample has the same weight, coarse grain ratio, etc., and the surface water rate of the used sand is calculated. A method for measuring surface water of sand is provided.

According to the above structure, when the saturated water absorption rate of the execution sample is subtracted from the saturated water rate of the reference sample, the value is the surface water rate of the used sand. Therefore, this surface water rate is added to the weight of the used sand. By multiplying, the amount of surface water is obtained, and the corrected amount of water added to the sand can be obtained based on this.

Further, according to the present invention, a container having an opening capable of supplying / draining sample sand, a water tank for soaking the sample sand together with the container having an opening capable of supplying / draining water, and a water tank receiver with a vibrator can be moved up and down. A water tank,
It consists of an electronic scale on which a container having the above-mentioned water supply / drainage opening is placed, and a water-absorbing cushion for receiving the above-mentioned container having the above-mentioned water supply / drainage opening is provided at the bottom of the water tank, and water supply and drainage to / from the water tank of the water tank are performed. It is intended to provide a surface water measuring device for sand, which is characterized by being moved up and down.

According to the above construction, the vibration of the vibrator promotes and equalizes the permeation of water during the submersion of the container having the opening through which water can be supplied and drained, and the water is saturated after the submersion of water. Is promoted. In addition, since excess water is absorbed by the water-absorbent cushion for weighing attached to a container having an opening through which water can be supplied and drained, accurate tare weight reduces weighing errors. Further, since water supply and drainage to and from the water tank depend on the upper and lower sides of the water supply tank, the structure is simplified and the water supply and drainage time is shortened.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, when sand is put in a container having an opening through which water can be supplied and drained, and then the container is pulled up into the container and water drops do not fall, that is, the adhesive force due to only surface tension is applied. The state of resisting the gravity of water is defined as "saturated state". However, the density of sand is unstable,
Therefore, the drainage is poor, and the saturated state is promoted by operating the vibrator for defoaming. The saturated water amount means the amount of water absorbed until reaching a saturated state, which is the amount of water obtained by replacing the voids in the apparent volume of sand with water.

Since it is assumed that the saturated water content is measured, according to the present invention, the surface water ratio of the sand sample is only 40%.
Since it is measured in seconds and can be used for quality control, it can be said to be an epoch-making measurement method. Considering the origin of the term surface water of sand, it is considered to indicate the surface wet state of one grain of sand. However, the reality is the amount of water in the voids of the sand. It is well known that the voids change depending on the apparent volume density. From this point of view, the saturated state is considered, and the saturated water state of sand is used based on specific gravity and coarse particle ratio to measure the amount of saturated water sand, and the calculation is expanded to a surface water rate measuring method.

It has been confirmed by experiments that the saturated water ratio is almost constant if the coarse particle ratio is constant. About this, the surface water ratio of sand is artificially set to 0 to 10%, and the saturated water ratio sample-treated is shown in the table.

[0013]

[Table 1]

According to the present invention, the saturated water rate absorbed in the surface dry state is determined for a reference sample which is divided stepwise from the specific gravity and the coarse particle rate (Table 2-1 and Table 3-1), and it is used as data. It is stored and managed (the average value of the saturated water ratio is 22.03, 21.49 respectively), and when the corrected water amount is calculated for the actual sand used, the sand of the execution sample reaches the saturated state in the surface water sand as it is. The saturated water absorption amount and the saturated water absorption that are absorbed up to the above are calculated (Table 2-2, Table 3-2), and the surface water ratio (10) of the used sand is calculated as the saturated water ratio. The error (12) is the error of the surface water rate in the Chapman method. In addition, Table 2 uses sand of the Jinzu River system of Toyama Prefecture, and Table 3 uses sand of the Shogawa River system of the same prefecture.

[0015]

[Table 2-1]

[0016]

[Table 2-2]

[0017]

[Table 3-1]

[0018]

[Table 3-2]

The saturated water ratio changes if either the specific gravity or the coarse grain ratio fluctuates. However, the saturated water ratios cancel each other out depending on the fluctuation ratio, and within the normal coarse grain ratio range of the ready-mixed concrete, the measurement error ±
Passing 0.5% or less easily.

[0020]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a perspective view showing a measuring device of the present invention, which is a representative example of a water tank 1, a water tank receiver 3 with a vibrator 4, and a "container having an opening capable of supplying and draining water". A net container 5 with a collar, a part of which is a net 6, and a flange 8 at the upper end, a water supply tank 7 for the water tank 1, an electronic scale 9 for measuring the weight of sand in the net container 5 with a collar, the measurement result and It is composed of a CPU printer 11 which outputs a calculation result. This measuring device is used for both measurement of the reference sample and the execution sample.

Regarding the water supply tank 7, 13 is a vertical drive cylinder, and 14 is a flexible tube made of rubber, which raises the water supply tank 7 to supply water to the water tank 1, and lowers it to drain water. In addition, a drain groove 16 is provided around the bottom of the water tank receiver 3,
A water absorbing cushion 15 is arranged along the inner side of 6.
By receiving the water tank 1 with the water absorbing cushion 15, not only the vibration of the vibrator 4 can be efficiently applied to the water tank 1, but also the absorption and drainage of water attached to the mesh container 5 with a collar at the time of drainage are promoted. . Further, the water tank receiver 3 is provided with a timer 17 for setting the operating time of the vibrator 4. First, the procedure for measuring the saturated water ratio will be described.

(Measurement of the amount of saturated water and sand) JIS A1102 (reference sample) or A111
Based on 1-3 (execution sample), the classified sand is weighed to a sample amount (for example, 400 g) according to the measured coarse particle ratio, using the sieved sand. The value is set to Ms for the execution sample and M for the reference sample. In the case of the reference sample, in order to prevent the deviation of the coarse particle ratio, the surface water ratio is arbitrarily set, and the sample is well blended in order to average the surface water ratio. The sample is placed in the mesh container 5 with a collar. Put the net container 5 with a collar in the water tank 1 and operate the vibrator 4 while immersing the sand in the water. As a result, the density becomes stable, drainage is improved, and air is removed. The water in the water tank 1 is drained by lowering the water supply tank 7. Further, the water adhering to the flanged net container 5 is absorbed by the water absorbing cushion 15. The net container 5 with a collar is pulled up, placed on the electronic scale 9, and the weight of saturated water and sand is measured. This value is M in the reference sample
1, Ms1 in the execution sample.

Obtaining the sample sand weights M and Ms and the saturated water sand weights M1 and Ms1 in this way, the calculation of the saturated water ratio is as follows.

(Saturated water rate of reference sample) A) Saturated water amount = M1−M B) Saturated water rate = A ÷ M × 100 (Saturated water rate measurement of data, 5 points or more) C) Reference saturated water rate = B (Lower limit value + upper limit value) / 2 That is, the saturated water rate (B) of the reference sample = (M1-M)
÷ M × 100 (saturated water absorption rate of execution sample) Similarly, for each execution sample, F) Saturated water absorption amount = Ms1−Ms G) Saturated water absorption rate = (Ms1−Ms) ÷ Ms × 100

From the above, the saturated water rate of the reference sample (stored as data) and the saturated water absorption rate of the execution sample (calculated for the sand used each time) were obtained, and thus the corrected water amount was obtained for the sand used. Therefore, the presumed surface water rate is calculated as follows. H) Surface water rate of execution sample = (saturated water rate C of reference sample−saturated water absorption rate G of execution sample) ÷ (1 + C / 10
0) Also, this is the surface water ratio (H) = {C- (Ms1-M
s) ÷ Ms × 100} ÷ (1 + C / 100). The portion of (Ms1−Ms) ÷ Ms × 100 is a measurement and calculation item when actual ready-mixed concrete is manufactured.

Therefore, regarding the used sand, the surface water amount = the weight of the used sand × the surface water ratio (H), the corrected water amount = the unit water amount of the used sand-the surface water amount, and this corrected water amount is mixed into the sand at the site.

Next, the setting of the control width based on the trend of the surface water ratio at the measuring point and the precautions will be described. a) H is measured at 5 or more points at regular intervals b) Reference surface water ratio = a Sum of 5 points / 5 The respective saturated water ratio difference of the measurement sample is calculated from this reference surface water ratio. c) Sand amount = Ms− (Ms × b / 100) d) Saturated water amount = Ms1-c e) Saturated water rate = d ÷ c × 100 f) Measuring point saturated water rate difference = e−C Reference saturated water rate On the reference line, make a trend graph of saturated water rate difference values at each measurement point, and set the upper and lower control limits of the measurement error allowable range. If it falls off, check the surface dry saturated water ratio (change the standard saturated water ratio).

The reference (average) measurement point surface water due to the surface water ratio
Calculate the rate. Surface water rate = {e− (Ms1−Ms) × 100 / Ms} ÷
The larger the value of (1 + e / 100) coarse grain ratio, the coarser the grain size (smaller surface area).
If the saturated water ratio decreases and becomes smaller, the particle size becomes finer.
(Large surface area), saturated water rate increases. So look at the sand
If the surface area of the applied volume changes, the surface water rate also changes. Change
And destabilizing the slump is an unmistakable fact
is there. From the above, pay attention to the stability of coarse grain ratio and specific gravity.
This is very important.

[Brief description of drawings]

FIG. 1 is a perspective view showing a sand surface water measuring device of the present invention.

[Explanation of symbols] 1 aquarium 3 water tank receiver 5 Net container with a collar 7 water tank 9 Electronic scale 15 Water-absorbent cushion

Claims (2)

[Claims] 1. Sand is sampled on a standard basis every time the weight, the coarse grain ratio, etc. are different, and the coarse grain ratio is kept constant to replace the voids in the apparent volume of the surface-dried sand with water. Then, by measuring the weight of the water as the saturated water amount, the saturated water ratio is obtained as data for each reference sample and stored and managed.The surface water ratio is equalized in order to know the corrected water amount for the sand used. Saturated water absorption of the run sample was obtained by replacing the voids in the apparent volume of the surface water sand with water and measuring the weight of the water as the saturated water absorption. A method for measuring the surface water of sand, wherein the surface water rate of the sand used is calculated by subtracting the saturated water absorption rate of the execution sample from the saturated water rate of the reference sample having the same weight, coarse particle rate, etc. to the sample. . 2. A container having a water supply / drainage opening for containing the sample sand, a water tank for soaking the sample sand with the container having the water supply / drainage opening, a water tank receiver with a vibrator, and a water supply tank capable of moving up and down. It consists of an electronic scale on which a container having the above-mentioned water supply / drainage opening is placed, and a water-absorbing cushion for receiving the above-mentioned container having the above-mentioned water supply / drainage opening is provided at the bottom of the water tank, and water supply and drainage to / from the water tank of the water tank are performed. An apparatus for measuring surface water of sand, which is characterized by being moved up and down.