JP2002131208A - Method for measuring density in saturated surface-dry condition, rate of water absorption, surface moisture ratio of aggregate and high-temperature aggregate cooling device used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for measuring the density in a saturated surface-dry condition, rate of water absorption, and surface moisture ratio of an aggregate capable of simplifying a measuring method, shortening measuring time, and obtaining measurement values with high reliability by simultaneously obtaining the density in a saturated surface-dry condition, percentage of water absorption, and the surface moisture ratio of the wet aggregate to be measured and a high-temperature aggregate cooling device used for the same. SOLUTION: Aggregate samples A and B of the same weight (m) are separated and acquired from the wet aggregate. The aggregate sample A is housed in a determining container, and water is added to measure gross weight W in a state filled with water. The aggregate sample B is heated and dried, to measure weight (m0) in an absolute dry condition and cooled to a normal temperature range. Then the aggregate sample B is housed in a determining container, and water is added to measure 9 gross weight W1, in a state filled water. From the measured values, the absolute capacities (s) and quantities (q) of water absorption of the aggregate sample A and B are obtained, to obtain the density ρ in a saturated surface-dry condition the rate of water absorption, and surface moisture ratio H.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a method for measuring a water absorption rate and a surface water rate, and a high-temperature aggregate cooling device used for the method.

[0002]

2. Description of the Related Art Aggregates of ready-mixed concrete are usually treated as wet aggregates having moisture adhered to the surface thereof. On the other hand, the quality of the aggregate is such that the aggregate contains water in a saturated state and has no water on its surface (hereinafter referred to as a surface dry state).
, That is, controlled by surface dry density and water absorption,
As for the moisture adhering to the aggregate surface, the ratio to the surface dry weight is managed as the surface water content. Wet aggregate is a natural material and is used in large quantities, so it is necessary to constantly measure these values and estimate and monitor the true values.

[0003] The test method of the surface dry density ρ and the water absorption Q of the fine aggregate is specified in JIS A 1109. According to the same regulation, when measuring the surface dry density ρ of fine aggregate, after leaving the aggregate sample left in water for 24 hours to absorb water and become saturated, air is spread thinly on a flat surface and dried, When the surface has some water, the aggregate sample is packed into a flow cone and tamped before the flow cone is lifted. Repeat this operation, when the aggregate cone slumps for the first time,
It is determined that the surface is in a dry state, the surface dry weight is measured using a pycnometer or a flask with a scale, and the density ρ is calculated.

[0004] However, it takes time to prepare the surface dry sample, and the flow condition differs depending on the grain shape of the aggregate, and the judgment of the surface dry condition varies from individual to individual. It is difficult to ask. Further, when determining the water absorption Q, after measuring the surface dry weight, the sample is dried to a constant weight to make it absolutely dry (hereinafter referred to as absolutely dry), and the reduced weight is taken as the water absorption. Errors in the dry state and individual differences are also reflected in the water absorption Q.

On the other hand, a method of testing the surface water ratio _{H 11} fine aggregate is defined in JIS A 1111. According to the provisions, calculated on the weight and volume of the aggregate sample (the weight of the replaced water sample), the surface water ratio H ₁₁ by applying Omoteinui density ρ determined by JIS A 1109 in the measured value Ask.

Further, the JIS A 1125, test method for the surface water ratio _{H 25} based on moisture content test method and the water content of the aggregate is defined. According to the same rule, the aggregate sample is dried and its weight is measured, and the water content Z
Look, we obtain a surface water ratio _{H 25} by applying a water absorption Q determined in JIS A1109.

[0007] The surface water ratio H ₁₁ and H ₂₅ are should match in theory, actually surface water ratio H ₁₁ and the surface water ratio H ₂₅ based on the respective prescription was collected fine aggregate When asked,
These values do not always match. This means that the values of the surface dry density ρ and the water absorption Q, which were obtained independently of the wet fine aggregate to be measured when calculating the surface water content, were used. This is due to errors and individual differences being reflected.

[0008] As described above, if the measured value has an individual difference, it cannot be handled technically, and if the measurement takes time, the number of times of measurement cannot be increased. When the measurement is performed by the method specified in JIS, it is difficult in operation to increase the number of times of measurement for obtaining the variance and estimating the true value from the measured value.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention eliminates individual differences in measured values, simplifies the measuring method, shortens the measuring time, and can increase the number of measurements.
The surface dry density, water absorption, and surface water content of the aggregate can be obtained by simultaneously obtaining the surface dry density, water absorption, and surface water content from the measured wet aggregate. An object of the present invention is to provide a method and a high-temperature aggregate cooling device used for the method.

[0010]

In order to achieve the above object, in the first method of the present invention, aggregate samples A and B having the same weight m are collected from a uniformly mixed wet aggregate, and the aggregates are collected. Sample A was stored in a quantitative container having a volume V, and water was added thereto, and the total weight W was measured in a full state. On the other hand, the aggregate sample B was heated and absolutely dried in a dry state. The aggregate sample B is cooled, and after cooling, the aggregate sample B is put in a quantitative container, and water is added. The total weight W1 is measured in a full state, and the absolute volumes s and the water absorption q of the aggregate samples A and B are measured. Absolute volume s = V− (W1−m0) / c1 Water absorption q = (W−m0) − (W1−m0) c / c1 where c and c1 are the total weights W and W1. Density of water added during measurement From this, the surface dry density, water absorption, and surface water content of the aggregate sample were determined.

In the above measurement, when the aggregate sample B is cooled to a room temperature range, the dry weight m1 is measured, and then the aggregate sample B is stored in a quantitative container, and water is added to determine the total weight W1 in a full state. The absolute volume s and the water absorption q of the aggregate samples A and B are obtained from the following formulas. Absolute volume s = V− (W1−m1) / c1 Water absorption q = (W−m0) − (W1−m1) ) C / c1 Here, c and c1 are the densities of water added at the time of measuring the total weights W and W1. From this, the surface dry density, the water absorption and the surface water content of the aggregate sample may be obtained.

In the second method of the present invention, an aggregate sample C having a weight of m is collected from the uniformly mixed wet aggregate, and the aggregate sample C is collected.
After measuring the absolute dry weight m0 in an absolutely dry state by heating, the aggregate sample C is cooled, and the aggregate sample C is cooled,
The sample and water are stored in a measuring container filled with water of sufficient volume P0 to cover the aggregate sample C in advance, and the sum of the volume of the sample and water is measured. Then, the pressure inside the measuring container is reduced to reduce the bubbles generated in the container. After removing and allowing the aggregate sample C to absorb water sufficiently, the volume sum P of the sample and water
2 is measured, and the absolute volume s and the water absorption q of the aggregate sample C are obtained from the following equation. Absolute volume s = P1-P0 Water absorption q = (P2-P1) c1, where c1 is the sum of the volumes P1, P2 Density of water used at the time of measurement From this, the surface dry density, water absorption, and surface water content of the aggregate sample were determined.

Further, when cooling the high-temperature aggregate sample B or C in the absolutely dry state, the container containing the aggregate sample is immersed in a cooling water bath filled with cooling water, and the aggregate sample is cooled. After cooling the aggregate sample until the temperature of the cooling water becomes equal, using the cooling water having the same temperature, the total full weight W1 of the aggregate sample and the water or the volume sum P1 and P2 of the aggregate sample and the water is used.
Was measured.

When cooling the high-temperature aggregate sample in the absolutely dry state, a flat container having good thermal conductivity for accommodating the aggregate sample and cooling water for immersing the flat container are filled. A cooling water tank, a circulating water tank for receiving and storing cooling water overflowing from the cooling water tank, and a high-temperature aggregate cooling device including a water pump for circulating cooling water in the circulating water tank to the cooling water tank. did.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the first method (weight method) for determining the amount of water absorption from the weight difference between a dry state and a saturated state in determining the surface dry density, water absorption, and surface water percentage of an aggregate. And a second embodiment based on a second method (volume method) for determining the amount of water absorption from a change in volume before and after water absorption. First, FIG. 1 shows an outline of a method for measuring the surface dry density, water absorption, and surface water content of aggregate based on the first method of the present invention.
This will be described below with reference to the drawings.

First, aggregate samples A and B of the same weight m are collected from a uniformly mixed wet aggregate (wet sand). Next, the aggregate sample A is housed in a quantitative container 11 (pycnometer) having a volume V and a weight P, and water is added thereto to measure a total weight W in a full state. At this time, the fixed amount container 11 is closed as shown in FIG.
It is preferable to use a container provided with 2 and having a contact surface between the container 11 and the lid 12 that can be hermetically sealed and sealed.
Then, as shown in FIG. 3, water enough to cover the aggregate sample is put in advance, and the aggregate sample is put into the aggregate sample, and the water contained in the aggregate particles is extracted while further adding water. After the measurement, the lid 12 is filled with water to wipe off overflowing water, and the total weight W is measured.

On the other hand, the aggregate sample B is heated and dried to be in an absolutely dry state, and the absolute dry weight m0 is measured. Next, the aggregate sample B
Is cooled to a normal temperature range (temperature t1), and the dry weight m1 is measured. Then, the aggregate sample B is accommodated in the quantitative container 11 and water is added to measure the total weight W1 in a full state. Water is added in advance to cover the aggregate sample at the time of water addition, the aggregate sample is put therein, the water is further added, the lid 12 is filled with water, the overflow water is wiped off, and the total weight W1 is measured as described above. The same as the case of the aggregate sample A, except that water having the same temperature t1 as that of the cooled aggregate sample B is prepared in advance to minimize water absorption into the aggregate sample B at the time of measurement. The work from the introduction of B to the cover being filled with water is performed in the shortest possible time. After the lid is covered, water absorption into the aggregate sample B progresses and bubbles are generated, but the total weight W1
Has no effect.

In the above measurement, the absolute dry weight m0 of the aggregate sample A is obtained by subtracting the weight of the internal water (water absorption q) and the weight of the surface water (surface water h) from the wet weight m. In addition, when the surface water is full, the surface water mixes with the added water. Therefore, when the water weight is L, the total weight W is expressed by the following equation. W = L + (m−h) = L + (m0 + q) Here, (m−h) and (m0 + q) are the surface dry weight of the aggregate sample A. FIG. 4A schematically shows the above relationship for one aggregate particle. The void portion inside the aggregate grain containing the water absorption q is minute and does not appear on the surface of the aggregate grain.

In the measurement of the aggregate sample B, the dry weight m1 is smaller than the absolute dry weight m0.
Although the weight has increased slightly due to the reattachment of moisture to the
For the sake of convenience, the following two extreme cases are assumed for the sake of convenience. (FIG. 4B) (1a) Assume that the reattached moisture remains on the surface of the aggregate grain until the time of hydration, that is, the increment of surface water is Δh; m1−m0 = Δh (1b) It is assumed that all are absorbed into the aggregate grains by the time of water addition, that is, the increment of water absorption is Δq; m1−m0 = Δq. In addition, even when the re-adhered moisture is not taken into consideration, the equation (1a)
Becomes Hereinafter, each case will be described.

First, in the case of (1a) where the amount of water reattached to the surface of the aggregate sample B is defined as an increment of surface water Δh, the increment of surface water Δh is mixed with the added water at the time of measuring the total weight W1, Assuming that this water weight is L1, the total weight W1 is represented by the following equation. W1 = L1 + m0 Here, in the full state of each of the aggregate samples A and B,
The volume of water removed by the aggregate samples A and B, that is, the absolute volumes s of the aggregate samples A and B are equal and the water weights L and
Since the water capacity corresponding to L1 is also equal, assuming that the density of water at the water temperatures t and t1 is c and c1, L = L1 · c / c1. Therefore, the absolute volumes s of the aggregate samples A and B and the water absorption q is obtained from the following equation. s = V-L1 / c1 = V- (W1-m0) / c1q = (W-m0)-(W1-m0) .c / c1

From these values, the absolute dry density ρ0, the surface dry density ρ, the water absorption rate Q, and the surface water rate H of the aggregate samples A and B can be obtained by the following equations. ρ0 = m0 / sρ = (m0 + q) / sQ = (q / m0) × 100 H = (h / m−h) × 100 = {(m−m0−q) / (m0 + q)} × 100 At the same time, the water content Z is also obtained by the following equation. Z = {(m−m0) / m0} × 100

In the case where the water re-adhering to the surface of the aggregate sample B is defined as an increment of water absorption Δq (1b), the increment of water absorption Δq is retained inside the aggregate grains even when the total weight W1 is measured. Therefore, assuming that the weight of the added water is L1 without mixing with the added water, the total weight W1 is represented by the following equation. W1 = L1 + m1 The absolute volumes s and water absorption q of the aggregate samples A and B can be obtained by the following equations. s = V-L1 / c1 = V- (W1-m1) / c1q = (W-m0)-(W1-m1) .c / c1

In order to minimize the absorption of water into the aggregate sample B during the measurement of the total weight W1, water having the same temperature t1 as that of the cooled aggregate sample B was prepared in advance and added with water. Aggregate sample B using the high-temperature aggregate cooling device 1 described in
Is cooled to the same temperature t1 as the cooling water in a short time, and the cooling water (isothermal water) at the same temperature t1 is advantageously added.

As shown in FIGS. 5 and 6, the high-temperature aggregate cooling device 1 is mainly composed of a flat container 2, a cooling water tank 3, a circulating water tank 4, a pump 5 and a case 6 accommodating them. The radiator 7 is used together.

The flat container 2 has a bat shape for flatly storing an aggregate sample, and is preferably made of a metal having good corrosion resistance and heat conductivity, such as stainless steel or enamel. The cooling water tank 3 accommodates the flat container 2 and brings cooling water into contact with the flat container 2, and a flow path of the cooling water between the inner bottom surface or the inner side surface of the cooling water tank 3 and the flat container 2. Flat container 2 so that
A support member 31 for supporting the flat container 2 is provided on the inner bottom surface, which is one size larger than that.

The circulating water tank 4 is supported in the case 6 by a supporting member 61 of the case 6, and a supporting member 41 for supporting the cooling water tank 3 is provided near an upper opening, and cooling water is provided around the cooling water tank 3. The cooling water tank 3 is configured to be slightly larger than the cooling water tank 3 so as to secure a flow path, and the supporting member 41 is formed with a step 42 that contacts the side surface of the cooling water tank 3. A pump 5 is provided at the inner bottom of the circulating water tank 4, and a discharge pipe 51 of the pump 5 is connected to the inlet 32 at the bottom of the cooling water tank 3.

A drain pipe 44 is connected to a drain port 43 at the bottom of the circulating water tank 4. The drain pipe 44 is preferably formed of a transparent hose, and is normally held upright along a water level scale 45 outside the case 6 to perform the function of a water level gauge for detecting the water level in the circulating water tank 4. It can be drained if knocked down. It should be noted that a water level gauge and a cock for drainage may be separately provided. The upper portion of the case 6 can be opened and closed by a lid 62, and a ventilation fan 64 is provided at an exhaust port 63 at the center of the lid 62.

The heat dissipating metal fitting 7 is formed by integrally connecting a plurality of heat dissipating plates 71 with a connecting plate 72 and is made of a metal having good heat conductivity such as aluminum. It has a function of inserting the heat radiating plate 71 and releasing the heat of the inner deep part of the aggregate sample to the outside. In the illustrated example, the heat radiating plate 71 protrudes only on the lower surface side of the connecting plate 72, that is, the upper end of each heat radiating plate 71 is connected by the connecting plate 72. Make the plate 71 protrude,
The heat exchange area with air may be increased.

When measuring the aggregate sample B (measurement after absolute dry weight m0) using the high-temperature aggregate cooling device 1 and the heat dissipating metal fitting 7 configured as described above, first, the heat dissipating metal fitting is attached to the measuring device. 7 is placed with the heat radiating plate 71 facing up, and the flat container 2 is further placed thereon for tare correction. The dry weight m0 is measured.

Next, the flat container 2 is lowered, and the aggregate sample B
After inserting the heat sink 71 of the heat sink 7 into the cooling water tank 3, the lid 62 of the case 6 is closed, the power switch is turned on, and the pump 5 and the ventilation fan 64 are operated. Then, the cooling water in the circulating water tank 4 is sent to the cooling water tank 3 by the water pump 5 and contacts the lower surface of the flat container 2 in the cooling water tank 3 so that the high-temperature aggregate sample stored in the flat container 2 B is cooled. Then, the cooling water overflowing from the cooling water tank 3 flows into the circulating water tank 4 again.

On the upper surface side of the flat container 2, an aggregate sample B
Aggregate sample B by the heat sink 7 and the ventilation fan 64 inserted into the
When about 30 minutes have passed, the high-temperature aggregate sample B is cooled to the normal temperature range, and the temperature of the cooling water also rises slightly, so that the aggregate sample B and the cooling water have substantially the same temperature.

Then, the pump 5 and the ventilation fan 64 are stopped, and after confirming that the temperature of the aggregate sample B and the temperature of the cooling water are the same with a thermometer, the flat container 2 is taken out of the case 6 while The cooling water in the circulating water tank 4 is drained through the drainage pipe 44 so that the aggregate sample B can be covered.
After the tare correction is performed by placing the quantitative container on a measuring instrument, the aggregate sample B in the flat container 2 is placed in the quantitative container 11, and the dry weight m1 is measured. Next, the quantitative container 11
Is removed from the weighing machine and tare correction is performed.
To 1, the cooling water in the circulating water tank 4 is added with water to make it full.

Next, FIG. 7 shows an outline of a method for measuring the surface dry density, the water absorption and the surface water content of the aggregate based on the second method (volume method) of the present invention.

First, uniformly mixed wet aggregate (wet sand)
, An aggregate sample C having a weight of m is collected from the sample, and the aggregate sample C is heated and dried to be in an absolutely dry state, the absolute dry weight m0 is measured, and then the aggregate sample C is cooled to a normal temperature range (temperature t1). I do. on the other hand,
A cooled aggregate sample C and water at the same temperature t1 are prepared, and a calibrated measuring container 21 (graded flask,
Water (temperature t1) in a volume P0 sufficient to cover the aggregate sample C in advance into a Chapman flask or the like,
The aggregate sample C is gently put therein, and the volume sum P1 of the sample and water at that time is measured. It is advantageous to use the high-temperature aggregate cooling device 1 described above to cool the aggregate sample C, and to prepare cooling water (isothermal water) at the same temperature t1 simultaneously with the cooling.

Next, the suction device 22 connected to the vacuum pump is attached to the opening of the measuring container 21 so that the measuring container 2
Reduce the pressure inside 1. Then, water absorption into the aggregate sample C is promoted, and air contained in the aggregate sample C is generated as air bubbles. This operation is repeated once or several times after returning to the atmospheric pressure, and the aggregate sample C is assumed to be in a saturated state when no bubbles are generated in the container.
Measure 2.

From the volume P0 measured as described above and the sum P1 and P2 of the volume of the aggregate sample C and the water, the absolute volume s and the water absorption q of the aggregate sample C are expressed by the density of water at the water temperature t1 as c
It is expressed by the following equation as 1. s = P1-P0q = (P2-P1) c1 From these values, the absolute dry density ρ0, the surface dry density ρ, the water absorption rate Q, and the surface water rate H of the aggregate sample C are obtained by the following equations. (H
Ρ0 = m0 / (P1-P0) ρ = {m0 + (P2-P1) c1} / (P1-P0) Q = {(P2-P1) c1 / m0} × 100 H = (h / m −h) × 100 = {(m−m0−q) / (m0 + q)} × 100 Further, the water content Z is obtained by the following equation, as in the first embodiment. Z = {(m−m0) / m0} × 100

In the case of the above volume method, the absolute volume s and the water absorption q of the aggregate sample C are directly derived from the volume P0 of water and the sum of volumes P1 and P2 of the aggregate sample C and water. The change in weight due to moisture re-adhered to the surface is not included in the equation, but when this is taken into consideration, as in the case of the weight method described above, the following two extreme cases, namely, the re-adhesion of water to the surface Assuming the case of setting the increment of water Δh (2a) and the case of setting the increment of water absorption Δq (2b), it can be obtained as follows. FIG. 9 schematically shows the above relationship for one aggregate particle.

First, in the case of (2a) where the amount of water re-adhered to the surface of the aggregate sample C is defined as an increment of surface water Δh (2a), the volume of the increment of surface water Δh is equal to the volume sum P1 of the aggregate sample C and water and P2
And the absolute volume s of the aggregate sample C,
The water absorption q is expressed by the following equation. s = P1-P0- (m1-m0) / c1q = (P2-P1) c1

In the case of (2b) where the amount of water re-adhered to the surface of the aggregate sample C is defined as the increment of water absorption Δq (2b), the volume of the increment of water absorption Δq becomes the volume sum P2 of the aggregate sample C and water. That is, the absolute volume s of the aggregate sample C and the water absorption q
Is represented by the following equation. s = P1-P0q = (P2-P1) c1 + (m1-m0) From any of these values, the absolutely dry density ρ of the aggregate C
0, the surface dry density ρ, the water absorption Q, and the surface water H may be obtained by the above equation.

[0040]

EXAMPLE 1 The following procedures were used to measure the surface dry density, water absorption and surface water content of the aggregate based on the first method (gravimetric method). (I) Samples A and B Samples A and B having a weight of m = 1000 g are collected by mixing well and uniformly absorbed wet fine aggregate. At the temperature t = 28 ° C. of the samples A and B and the water, the density of the water is c = 0.99623 g / cc according to the scientific chronological table. (Ii) Quantitative container Internal volume V = 1004.3 cc, weight P = 1258.4 g (iii) Measurement of sample A About 300 cc, water temperature t = 28 ° C. was put into the quantitative container,
Next, put sample A, evacuate air, fill it with water, cover it,
The overflowing water was wiped off and the total weight was measured. Total weight T (= W + P) = 2840.8 g (iv) Measurement of sample B Sample B is placed in a heat-resistant container and heated to make it absolutely dry. The absolute dry state is determined when a glass plate is placed on the sample and no more clouding due to moisture is observed. Then, the flat container 2 and the heat dissipating metal fitting 7 were placed on a weighing instrument and tare-corrected. Then, the sample B was charged into the flat container 2 and the absolute dry weight m0 was measured. Absolute dry weight m0 = 925.3 g The flat container 2 and the heat dissipating metal fittings 7 are set in the high-temperature aggregate cooling device 1, cooled to a temperature t1 = 28 ° C.
After cc of water was put on the measuring instrument and tare-corrected, the sample B was put into the quantitative container and the weight m1 was measured. Dry weight m1 = 929.3 g The fixed-quantity container was taken down from the measuring instrument, tare-corrected, water was added to the fixed-quantity container with water of the same temperature, and the container was covered with water. Total weight T1 (= W1 + P) = 2823.7 g (v) Calculation of absolute volume and water absorption (1a) The absolute volume and water absorption were determined as the amount of water re-adhered to the surface of the aggregate sample B as an increment of surface water Δh. Was. Absolute volume s = V- (W1-m0) / c1 = 361.
9cc water absorption q = (W-m0)-(W1-m0) .c / c
1 = 17.1 g (vi) Calculation of absolute dry density, surface dry density, water absorption, surface water content, moisture content (1a) absolute dry density ρ0 = m0 / s = 2.557g table dry density ρ = (m0 + q) /S=2.604 g Water absorption rate Q = (q / m0) × 100 = 1.85% Surface water rate H = (m−m0−q) / (m0 + q)｝ × 1
00 = 6.11% water content Z = {(m−m0) / m0} × 100 = 8.
07%

[0041]

Example 2 The following procedures were used to measure the surface dry density, water absorption and surface water content of the aggregate based on the second method (volume method). (I) Sample C A uniform fine and sufficiently absorbed wet fine aggregate is mixed well to obtain a sample C having a weight of m = 500 g. (Ii) Measuring Container A Chapman flask as shown in FIG. The Chapman flask is a gourd-shaped and has scales at the center (190 to 210) and the upper part (375 to 500). However, since there are errors in the scale and the internal volume, calibration is performed in advance by the following procedure. First, a Chapman flask was placed on a measuring instrument to perform a tare correction. Then, water at a water temperature t was filled up to each scale to determine the weight u of the water, and the internal volume V was calculated as V = u /
Obtain with c. c is the density of water at the water temperature t. In the embodiment, the water temperature is t = 21 ° C., and the density of water is c = 0.99799 g / cc according to the science chronological table. The results are shown in FIG.
Shown in

(Iii) Measurement of Absolute Dry Weight and Absolute Volume of Sample C Sample C is placed in a heat-resistant container and heated to an absolutely dry state.
The determination of the absolute dry state was performed in the same manner as in Example 1. Then, the flat container 2 and the heat dissipating metal fitting 7 were placed on a weighing machine and tare-corrected. Then, the sample C was charged into the flat container 2 and the absolute dry weight m0 was measured. Absolute dry weight m0 = 465.0 g The flat container 2 and the heat dissipating metal fitting 7 were set in the high-temperature aggregate cooling device 1 and cooled to a temperature t1 = 27 ° C. After cooling, when the dry weight m1 was measured, it was m1 = 466.3 g.
Cooling water having a temperature of t1 = 27 ° C.
Insert up to the 01cc scale. From Table 1, P0 = 20
0cc. Next, when the sample C was placed in the Chapman flask and the scale was read, it was 395 cc.
Since the error of the scale at 00 cc is -1.5, the volume sum P1 = 395-1.5 = 393.5 cc, and the absolute volume s of the sample C is absolute volume s = P1-P0 = 193.5 cc (iv) Measurement of water absorption of sample C A suction device was attached to the mouth of the Chapman flask and connected to a vacuum pump. This operation was performed three times under reduced pressure, and it was confirmed that there were no bubbles. The scale at this time was 387 cc. Since the density of water at the temperature t1 = 27 ° C. is c1 = 0.96551 g / cc according to the scientific chronological table, the water absorption q = (P2−P1) c1 = (395-387) × 0.99651 = 7. 97g (v) Calculation of absolute dry density, surface dry density, water absorption, surface water content, moisture content Absolute dry density ρ0 = m0 / s = 2.410g Surface dry density ρ = (m0 + q) /s=2.451 g Water absorption Rate Q = (q / m0) × 100 = 1.709% Surface water rate H = (m−m0−q) / (m0 + q)｝ × 1
00 = 5.43% Water content Z = {(m−m0) / m0} × 100 = 7.
23%

[0043]

As described in detail above, the present invention separates aggregate samples A and B having the same weight m from uniformly mixed wet aggregates.
Aggregate sample A was accommodated in a fixed volume container having a volume V, and water was added to measure the total weight W in a full state, while aggregate sample B was heated and absolutely dried in a dry state, and the absolute dry weight m0 was measured. Thereafter, the aggregate sample B was cooled to a room temperature range (measured dry weight m1),
Next, the aggregate sample B was accommodated in a quantitative container, and water was added thereto. The total weight W1 was measured in a full state, and the absolute volume s and the water absorption q of the aggregate samples A and B were calculated from these measured values. Since the surface dry density, water absorption, and surface water content of aggregate samples are determined, there is no need to prepare surface dry samples, eliminating individual differences in measured values, simplifying the measurement method, and shortening the measurement time. By doing so, the number of measurements can be increased, and by simultaneously obtaining the surface dry density, water absorption and surface water content from the measured wet aggregate, highly reliable measurement values can be obtained, and the quality of the aggregate can be obtained. This is advantageous for management and formulation design.

Further, according to the present invention, an aggregate sample C having a weight of m is collected from a uniformly mixed wet aggregate, and the aggregate sample C is heated to determine the absolute dry weight m0 in an absolutely dry state. The aggregate sample C is cooled, and after cooling, the aggregate sample C is housed in a measuring container previously filled with water having a volume P0 sufficient to cover the aggregate sample C, and the volume sum of the sample and water P1 Then, the pressure inside the measuring container is reduced to remove air bubbles generated in the container, and the aggregate sample C is sufficiently absorbed. Then, the volume sum P2 of the sample and water is measured. Since the absolute volume s and the water absorption q of the aggregate sample C were calculated and the surface dry density, water absorption and surface water content of the aggregate sample were determined, it is necessary to prepare the surface dry sample as in the above case. The number of measurements can be increased by eliminating individual differences in measurement values, simplifying the measurement method and shortening the measurement time. In addition, it is possible to obtain a highly reliable measurement value by simultaneously obtaining the surface dry density, the water absorption rate, and the surface water rate from the measured wet aggregate, so that the quality control and the mixing design of the aggregate can be performed. It is advantageous.

In each of the above methods, when cooling the high-temperature aggregate sample in an absolutely dry state, the container containing the aggregate sample is immersed in a cooling water bath filled with cooling water, and the aggregate sample is cooled. After cooling the aggregate sample until the temperature of the cooling water becomes equal, the total weight W1 of the aggregate sample and water or the volume sum P1 of the aggregate sample and water using the cooling water having the same temperature is used.
Since P2 is measured, there is an advantage that a high-temperature aggregate sample can be cooled down to a normal temperature range in a short time and cooling water (isothermal water) having the same temperature as the aggregate sample can be simultaneously prepared.

The high-temperature aggregate cooling device used for cooling the high-temperature aggregate sample in the absolutely dry state includes a flat container having good heat conductivity for accommodating the aggregate sample, A cooling water tank filled with cooling water for immersion, a circulating water tank for receiving and storing the cooling water overflowing from the cooling water tank, and a water pump for circulating the cooling water in the circulating water tank to the cooling water tank. With such a configuration, there is an advantage that a high-temperature aggregate sample can be cooled to a normal temperature range in a short time, and cooling water (isothermal water) having the same temperature as the aggregate sample can be simultaneously prepared.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a measurement procedure according to a method of a first embodiment of the present invention.

FIG. 2A is a longitudinal sectional view showing an embodiment of a fixed amount container in a state where a lid is opened, and FIG.

FIG. 3 (a) shows a state where water for covering an aggregate sample is put in,
(B) is a state in which the aggregate sample is charged, (c) is a state in which the lid is closed after adding water to the quantitative container, and (d) is a longitudinal sectional view showing a full state in which excess water is discharged by the lid.

FIG. 4 is a view schematically showing a state change of an aggregate sample in the method according to the first embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing the high-temperature aggregate cooling device according to the embodiment of the present invention.

FIG. 6 is an essential part perspective view showing an exploded state of the high-temperature aggregate cooling device according to the embodiment of the present invention.

FIG. 7 is a diagram schematically illustrating a measurement procedure according to the method of the second embodiment of the present invention.

FIG. 8A shows a Chapman flask,
(B) is a table showing the calibration results.

FIG. 9 is a view schematically showing a state change of an aggregate sample in the method according to the second embodiment of the present invention.

[Explanation of symbols]

 A, B, C Aggregate sample 1 High-temperature aggregate cooling device 2 Flat container 3 Cooling water tank 4 Circulating water tank 5 Pumping pump 6 Case 7 Heat dissipating metal fitting 11 Quantitative container 12 Lid 21 Measuring container 22 Aspirator

Claims (5)

[Claims] 1. Aggregate samples A and B having the same weight m are collected from a uniformly mixed wet aggregate, and the aggregate sample A is accommodated in a fixed volume container having a volume V, and water is added thereto. On the other hand, after measuring the absolute dry weight m0 in an absolutely dry state by heating the aggregate sample B, the aggregate sample B is cooled, and after cooling, the aggregate sample B is placed in a quantitative container. The total weight W1 was measured in a water-filled state by containing and adding water, and the absolute volumes s of the aggregate samples A and B were measured.
And the water absorption q is determined by the following equation: Absolute volume s = V− (W1−m0) / c1 Water absorption q = (W−m0) − (W1−m0) c / c1 where c and c1 are the total weight. Density of water added during measurement of W and W1 From this, the surface dry density, water absorption and surface water content of the aggregate sample are determined, and the measurement of the surface dry density, water absorption and surface water content of the aggregate is performed. Method. 2. Aggregate samples A and B having the same weight m are collected from the uniformly mixed wet aggregate, and the aggregate sample A is accommodated in a quantitative container having a volume V, and water is added to the aggregated sample to obtain a total weight W in a full state. On the other hand, the aggregate sample B is heated and the absolute dry weight m0 is measured in an absolutely dry state, and then the aggregate sample B is cooled to a room temperature range to measure the dry weight m1, and then The aggregate sample B was accommodated in a quantitative container and water was added thereto, and the total weight W1 was measured in a full state,
The absolute volume s and the water absorption q of the above aggregate samples A and B are obtained by the following equation. Absolute volume s = V− (W1−m1) / c1 Water absorption q = (W−m0) − (W1−m1) c / C1 where c and c1 are the density of water added at the time of measuring the total weight W and W1. From this, the surface dry density, water absorption and surface water content of the aggregate sample are determined. A method for measuring dry density, water absorption and surface water content. 3. An aggregate sample C having a weight of m is collected from the uniformly mixed wet aggregate, the aggregate sample C is heated, and the absolute dry weight m0 is measured in an absolutely dry state. The sample C is cooled, and after cooling, the aggregate sample C is housed in a measuring container filled with water having a volume P0 sufficient to cover the aggregate sample C in advance, and the volume sum P1 of the sample and water is measured. Then, the pressure in the measuring container is reduced to remove bubbles generated in the container, and the aggregate sample C is sufficiently absorbed by water. Then, the volume sum P2 of the sample and water is measured, and the aggregate sample C is measured.
Absolute volume s and water absorption q are obtained from the following equation. Absolute volume s = P1−P0 Water absorption q = (P2−P1) c1 where c1 is the density of water used when measuring the volume sums P1 and P2. A method for measuring the surface dry density, water absorption, and surface water content of an aggregate, comprising determining the surface dry density, water absorption, and surface water content of an aggregate sample. 4. When cooling a high-temperature aggregate sample in an absolutely dry state, a container accommodating the aggregate sample is immersed in a cooling water bath filled with cooling water, and the temperature of the aggregate sample and the cooling water is reduced. After cooling the aggregate sample until the water content of the aggregate sample becomes equal, the total weight W1 of the aggregate sample and water or the sum of the volumes P1 and P2 of the aggregate sample and water is measured using cooling water having the same temperature. The surface dry density, water absorption, and the aggregate of the aggregate according to claim 1, 2 or 3.
How to measure surface water content. 5. A flat container having high thermal conductivity for storing a high-temperature aggregate sample, a cooling water tank filled with cooling water for immersing the flat container, and receiving and storing cooling water overflowing from the cooling water tank. 5. A circulating water tank for circulating water, and a pump for circulating cooling water in the circulating water tank to the cooling water tank.
A high-temperature aggregate cooling device used in the described measuring method.