JP3398863B2 - Method for measuring surface dry density, water absorption and surface water content of aggregate, and high-temperature aggregate cooling device used therefor - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surface dry density of aggregate,
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 therefor.

[0002]

2. Description of the Prior Art Aggregate of ready-mixed concrete is usually treated as wet aggregate with water adhering to its surface. On the other hand, the quality of the aggregate is a state in which the aggregate contains water in a saturated state and the surface thereof has no water (hereinafter referred to as a surface dry state).
Is controlled by the density at, that is, the surface dry density and the water absorption rate,
Regarding the water adhering to the surface of the aggregate, the ratio with the surface dry weight is managed as the surface water ratio. Since many wet aggregates are natural substances and are used in large amounts, it is necessary to constantly measure these values and estimate the true values for monitoring.

The test method for the surface dry density ρ and the water absorption rate Q of the fine aggregate is specified in JIS A 1109. According to the same regulations, when measuring the surface dry density ρ of fine aggregate, the aggregate sample is allowed to stand in water for 24 hours to absorb water to make it saturate, and then spread on a flat surface to blow and dry. When the surface has some water, the aggregate sample is packed in a flow cone and tamped before the flow cone is pulled up. Repeating this operation, when the aggregate cone slumps for the first time,
It is said that the surface dry condition is judged and the surface dry weight is measured using a pycnometer or a graduated flask to calculate the density ρ.

However, it takes time to prepare the above-mentioned surface dry sample, and the flow state varies depending on the particle shape of the aggregate, and there are individual differences in the judgment of the surface dry state. It is difficult to ask. Further, when determining the water absorption rate Q, after measuring the surface dry weight, the sample is dried to a constant weight and brought to an absolute dry state (hereinafter referred to as absolutely dry state), and the reduced weight is taken as the water absorption amount. The error in the dry state and the individual difference are also reflected in the water absorption rate Q.

On the other hand, the test method for the surface water ratio H ₁₁ of fine aggregate is specified in JIS A 1111. According to this regulation, the weight and volume of the aggregate sample (weight of water replaced by the sample) is obtained, and the surface dryness ρ obtained by JIS A 1109 is applied to the measured value to determine the surface water ratio H ₁₁ . Ask.

In addition, JIS A 1125 defines a method for testing the water content of aggregates and a method for testing the surface water content H ₂₅ based on the water content. According to the same regulation, the aggregate sample is dried and weighed, and the water content Z
Then, the water absorption rate Q obtained according to JIS A1109 is applied to obtain the surface water rate H ₂₅ .

The above-mentioned surface water ratios H ₁₁ and H ₂₅ should theoretically agree with each other, but fine aggregate is actually sampled and the surface water ratios H ₁₁ and H ₂₅ are calculated based on the respective regulations. When asked,
These values do not always match. This is because the values of the surface dry density ρ and the water absorption rate Q, which were obtained independently of the wet fine aggregates used in the calculation of the surface water ratio, were used, and these values are related to the surface dry state. This is because the error and individual difference are reflected.

If individual differences occur in the measured values in this way, it is technically impossible to handle, and if the measurement takes time, the number of measurements cannot be increased. When measuring by the method specified by JIS, it is difficult to increase the number of times of measurement for obtaining the variance and estimating the true value from the measured value.

[0009]

In view of the above points of the prior art, the present invention eliminates individual differences in measured values, simplifies the measuring method, and shortens the measuring time, thereby increasing the number of measurements.
Moreover, it is possible to obtain highly reliable measurement values by simultaneously obtaining the surface dry density, water absorption rate, and surface water rate from the measured wet aggregate. Measurement of the surface dry density, water absorption rate, and surface water rate of the aggregate. The purpose of the present invention is to provide a method and a high-temperature aggregate cooling device used therefor.

[0010]

In order to achieve the above object, according to the first method of the present invention, aggregates A and B having the same weight m are collected from uniformly mixed wet aggregates to obtain aggregates. Sample A was placed in a fixed volume container of volume V and water was added to measure the total weight W in a full state. On the other hand, aggregate sample B was heated to measure the absolute dry weight m0 in an absolute dry state, The aggregate sample B is cooled, and after cooling, the aggregate sample B is stored in a fixed quantity container and water is added to measure the total weight W1 in a full state, and the absolute volume s and the water absorption amount q of the aggregate samples A and B are measured. The absolute volume s = V- (W1-m0) / c1 water absorption q = (W-m0)-(W1-m0) c / c1 where c and c1 are the total weight W and W1, respectively. Density of water added during measurement From this, the surface dry density, water absorption rate, and surface water rate of the aggregate sample were determined.

In the above measurement, the dry weight m1 is measured when the aggregate sample B is cooled to a room temperature range, and then the aggregate sample B is stored in a fixed quantity container to add water to obtain the total weight W1. Absolute volume s = V- (W1-m1) / c1 Absolute volume s = V- (W1-m1) / c1 Water absorption q = (W-m0)-(W1-m1 ) C / c1 where c and c1 are the densities of water added when the total weights W and W1 are measured, and the surface dry density, water absorption rate and surface water rate of the aggregate sample may be obtained from this.

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.
Is heated to measure the absolute dry weight m0 in an absolutely dry state, the aggregate sample C is cooled, and after cooling, the aggregate sample C is
The aggregate volume C of the sample and water was measured by accommodating in a measuring container containing water having a volume P0 sufficient to cover the aggregate sample C in advance, and then the pressure inside the measuring container was reduced to remove bubbles generated in the container. After removing and allowing the aggregate sample C to absorb water sufficiently, the total volume P of the sample and water P
2 is measured, and the absolute volume s and the water absorption amount q of the aggregate sample C are obtained from the following equations: Absolute volume s = P1-P0 Water absorption amount q = (P2-P1) c1 where c1 is the sum of volume P1 and P2 Density of water used at the time of measurement From this, the surface dry density, water absorption rate, and surface water rate 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 tank filled with cooling water to form an aggregate sample. After cooling the aggregate sample until the temperature of the cooling water becomes equal, the total weight W1 of the aggregate sample and water filled with water or the volume sum P1 and P2 of the aggregate sample and water using the cooling water having the same temperature.
Was measured.

When cooling the absolutely dry high temperature aggregate sample, a flat container having good thermal conductivity for accommodating the aggregate sample and cooling water for immersing the flat container are stretched. 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 equipped with a pump for circulating the cooling water in the circulating water tank to the cooling water tank. did.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is the first method (gravimetric method) for obtaining the water absorption amount from the weight difference between the dry state and the saturated state when obtaining the surface dry density, water absorption rate and surface water rate of aggregate. There is a second embodiment based on the second method (volume method) for obtaining a water absorption amount from a volume change before and after water absorption. First, FIG. 1 shows an outline of a method for measuring the surface dry density, water absorption rate and surface water rate of an aggregate based on the first method of the present invention.
Hereinafter, description will be given with reference to the drawings.

First, aggregate samples A and B having the same weight m are collected from the wet aggregate (wet sand) that is uniformly and sufficiently mixed. Next, the aggregate sample A is stored in a quantitative container 11 (pycnometer) having a volume V and a weight P, and the total weight W is measured in a water-filled state. At this time, the fixed quantity container 11 has a lid 1 as shown in FIG.
It is preferable to use a container provided with 2 and capable of sealing the contact surface between the container 11 and the lid 12 by laminating.
Then, as shown in FIG. 3, water is added in advance to cover the aggregate sample, and the aggregate sample is poured into the aggregate sample while further adding water to remove the air contained in the aggregate particles. After the measurement, the lid 12 is covered with the water full and the overflowed water is wiped off, and the total weight W is measured.

On the other hand, the aggregate sample B is dried by heating and drying, and the absolute dry weight m0 is measured. Then, the aggregate sample B
After cooling to a room temperature range (temperature t1) to measure the dry weight m1, the aggregate sample B is stored in the quantitative container 11 and water is added to measure the total weight W1 in a full state. In the case of adding water, water is added in advance to cover the aggregate sample, the aggregate sample is put therein, and the cover 12 is further added with water, and the overflowed water is wiped off to measure the total weight W1. Similar to the case of the aggregate sample A, in order to minimize water absorption into the aggregate sample B at the time of measurement, water having the same temperature t1 as that of the cooled aggregate sample B is prepared in advance, and the aggregate sample is Perform the work from the addition of B to the lid covering with full water in the shortest possible time. After the lid is covered, water is absorbed into the aggregate sample B and bubbles are generated, but the total weight W1
Does not affect

In the above measurement, the absolute dry weight m0 of the aggregate sample A is obtained by subtracting the weight of internal water (water absorption amount q) and the weight of surface water (surface water amount h) from the wet weight m. Moreover, since the surface water mixes with the added water in a full state, the total weight W is represented by the following equation, where L is the weight of the water. W = L + (m−h) = L + (m0 + q) Here, (m−h) and (m0 + q) are surface dry weights of the aggregate sample A. FIG. 4A schematically shows the above relationship for one aggregate grain. The voids inside the aggregate particles containing the water absorption amount q are minute and do not appear on the surface of the aggregate particles.

In the measurement of the aggregate sample B, the dry weight m1 is more than the absolute dry weight m0, and the aggregate sample B during cooling is
Although the weight has increased slightly due to the reattachment of water to the
For the sake of convenience, the following two extreme cases are assumed. (FIG. 4B) (1a) The reattached water remains on the surface of the aggregate grains until the time of water addition, that is, the surface water increment Δh; m1-m0 = Δh (1b) The reattached water is It is assumed that all are absorbed inside the aggregate grains by the time of water addition, that is, the increment of water absorption is Δq; m1-m0 = Δq Actually, it is considered that these are intermediate states. Even when the reattached moisture is not taken into consideration, the above formula (1a) is used in the mathematical formula.
Becomes Each case will be described below.

First, in the case where the moisture reattached to the surface of the aggregate sample B is set as the surface water increment Δh (1a), the surface water increment Δh is mixed with the water added when the total weight W1 is measured, When this water weight is L1, the total weight W1 is expressed 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 weight L,
Since the water volume corresponding to L1 is also equal, if the density of water at the water temperature t, t1 is c, c1, then L = L1 · c / c1. Therefore, the absolute volume s and water absorption of the aggregate samples A and B are q is calculated by the following equation. s = V-L1 / c1 = V- (W1-m0) / c1 q = (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 are calculated by the following equations. ρ0 = m0 / s ρ = (m0 + q) / sQ = (q / m0) × 100 H = (h / m−h) × 100 = {(m−m0−q) / (m0 + q)} × 100 Further, In addition, the water content Z is also calculated by the following formula. Z = {(m-m0) / m0} × 100

Further, in the case where the moisture reattached to the surface of the aggregate sample B is set as the water absorption increment Δq (1b), the water absorption increment Δq is retained inside the aggregate grains even when the total weight W1 is measured. Therefore, the total weight W1 is represented by the following equation, where L1 is the weight of the added water that is not mixed with the added water. W1 = L1 + m1 Then, the absolute volume s and the water absorption amount q of the aggregate samples A and B are obtained by the following equations. s = V-L1 / c1 = V- (W1-m1) / c1 q = (W-m0)-(W1-m1) .c / c1

In order to minimize water absorption into the aggregate sample B when measuring the total weight W1, water having the same temperature t1 as that of the cooled aggregate sample B was prepared in advance and watered. Using the high-temperature aggregate cooling device 1 described in 1., aggregate sample B
It is advantageous to cool the water to the same temperature t1 as the cooling water in a short time and add the cooling water (isothermal water) having the same temperature t1.

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 pumping pump 5, and a case 6 for accommodating them. The heat sink 7 is also used.

The flat container 2 has a bat shape for accommodating the aggregate sample by spreading it flat, and is preferably made of a metal such as stainless steel or enamel having good corrosion resistance and thermal conductivity. The cooling water tank 3 is for accommodating the flat container 2 and bringing cooling water into contact with the flat container 2, and a cooling water flow path is provided between the inner bottom surface or the inner surface of the cooling water tank 3 and the flat container 2. Flat container 2 to secure
A support member 31 for supporting the flat container 2 is provided on the inner bottom surface so as to be slightly larger.

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

A drainage pipe 44 is connected to the drainage port 43 at the bottom of the circulating water tank 4. The drainage pipe 44 is preferably composed of a transparent hose, and usually serves as a water level gauge that is held upright along a water level scale 45 outside the case 6 to detect the water level in the circulating water tank 4, and during drainage. It can be drained if it is laid down. A water level gauge and a drain cock may be provided separately. The upper portion of the case 6 can be opened and closed by a lid 62, and a ventilation fan 64 is provided at the exhaust port 63 at the center of the lid 62.

The heat dissipating metal member 7 is composed of a plurality of heat dissipating plates 71 integrally connected by a connecting plate 72 and is made of a metal having a good thermal conductivity such as aluminum. It has a function of inserting the heat radiating plate 71 to release the heat of the inner deep portion of the aggregate sample to the outside. In the illustrated example, the heat radiating plate 71 projects only to 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. Project the plate 71,
The heat exchange area with air may be increased.

When the aggregate sample B is measured (measurement after the absolute dry weight m0) by using the high temperature aggregate cooling device 1 and the heat sink 7 configured as described above, first, the heat sink is attached to the scale. 7 is placed with the heat radiating plate 71 on top, and the flat container 2 is further placed thereon to perform tare correction, and then the aggregate sample B in an absolutely dry state is put into the flat container 2 and cut. Measure the dry weight m0.

Next, the flat container 2 is unloaded, and the aggregate sample B
After inserting the heat sink 71 of the heat sink 7 into the cooling water tank 3, the flat container 2 is set in the cooling water tank 3, the cover 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 pumping pump 5 sends the cooling water in the circulating water tank 4 to the cooling water tank 3, and when the cooling water tank 3 comes into contact with the lower surface of the flat container 2, the high temperature aggregate sample contained 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, the aggregate sample B
Aggregate sample B by heat sink 7 and ventilation fan 64 inserted in
After about 30 minutes, the high temperature aggregate sample B is cooled to the normal temperature range, the cooling water temperature is slightly raised, and the aggregate sample B and the cooling water have almost the same temperature.

Then, after stopping the pumping pump 5 and the ventilation fan 64 and confirming that the temperature of the aggregate sample B and the cooling water are the same with a thermometer, the flat container 2 is taken out from the case 6, Quantitative container (pycnometer) to the extent that the cooling water in the circulating water tank 4 can be covered with the aggregate sample B through the drainage pipe 44
Then, the aggregate container B in the flat container 2 is placed in the quantitative container 11 and the dry weight m1 is measured. Then, the fixed quantity container 11
While unloading the meter from the weighing machine and performing tare correction,
The cooling water in the circulating water tank 4 is watered to 1 to fill up the water, the fixed amount container 11 is covered with the lid 12, and the overflowed water is wiped off, and the total weight W1 is measured.

Next, an outline of a method for measuring the surface dry density, water absorption rate and surface water rate of the aggregate based on the second method (volumetric method) of the present invention is shown in FIG. 7 and will be described below with reference to the drawings.

First, the uniformly mixed wet aggregate (wet sand)
The aggregate sample C having a weight of m is sampled from the sample, 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). To do. on the other hand,
Prepared water having the same temperature t1 as that of the cooled aggregate sample C, and calibrated the measuring container 21 (a graduated flask,
In a Chapman flask or the like), water (temperature t1) having a sufficient volume P0 to cover the aggregate sample C is put in advance,
The aggregate sample C is gently put therein, and the volume sum P1 of the sample and water at that time is measured. For cooling the aggregate sample C, it is advantageous to use the above-described high-temperature aggregate cooling device 1 and prepare cooling water (isothermal water) having the same temperature t1 simultaneously with cooling.

Next, the suction device 22 connected to the vacuum pump is attached to the opening of the measuring container 21 to attach it to the measuring container 2.
The pressure in 1 is reduced. Then, the water absorption into the aggregate sample C is promoted, and the air contained in the aggregate sample C is generated as bubbles. This operation is performed once or returned to atmospheric pressure and repeated several times, and the aggregate sample C is assumed to be in a saturated state with no bubbles generated in the container.
Measure 2.

From the volume P0 measured as described above and the volume sums P1 and P2 of the aggregate sample C and the water, the absolute volume s and the water absorption amount q of the aggregate sample C are the density c of water at the water temperature t1.
It is represented by the following formula as 1. s = P1-P0 q = (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 calculated by the following equations. (H
Is the amount of surface water) 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 Moreover, the water content Z is calculated | required by the following formula like the said 1st embodiment. Z = {(m-m0) / m0} × 100

In the case of the above volume method, the absolute volume s and the water absorption amount q of the aggregate sample C are directly derived from the volume P0 of water, the aggregate volume P1 and P2 of the aggregate sample C and water, and therefore during cooling. The weight change due to the redeposited water is not included in the equation. However, when considering this, as in the case of the weight method described above, the following two extreme cases, that is, the reattached water is Assuming that the increment of water is Δh (2a) and the increment of water absorption is Δq (2b), it can be calculated as follows. FIG. 9 schematically shows the above relationship for one aggregate grain.

First, in the case where the moisture reattached to the surface of the aggregate sample C is set as the surface water increment Δh (2a), the volume of the surface water increment Δh corresponds to the aggregate volume C1 of the aggregate sample C and water. P2
, The absolute volume s of the aggregate sample C,
The water absorption amount q is represented by the following equation. s = P1-P0- (m1-m0) / c1 q = (P2-P1) c1

When the water content reattached to the surface of the aggregate sample C is used as the water absorption increment Δq (2b), the volume of the water absorption increment Δq becomes the aggregate volume P2 of the aggregate sample C and water. Since it is included, the absolute volume s and the water absorption amount q of the aggregate sample C are included.
Is expressed by the following equation. s = P1-P0 q = (P2-P1) c1 + (m1-m0) From any of these values, the absolute dry density ρ of the aggregate sample C is obtained.
0, the surface dry density ρ, the water absorption rate Q, and the surface water rate H may be obtained by the above equations.

[0040]

Example 1 The following procedure was used to measure the surface dry density, water absorption rate, and surface water rate of aggregates 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 thoroughly mixing the wet fine aggregates that are uniformly and sufficiently absorbed with water. Samples A and B and the temperature of water t = 28 ° C., the density of water is c = 0.99623 g / cc according to the science chronology. (Ii) Volume of fixed amount container V = 1004.3 cc, weight P = 1258.4 g (iii) Measurement of sample A Water of about 300 cc and water temperature t = 28 ° C. was put in the fixed amount container,
Next, add sample A, bleed air to make it full of water, and close the lid.
The overflowed water was wiped off and the total weight was measured. Total weight T (= W + P) = 2840.8 g (iv) Measurement of sample B Put sample B in a heat-resistant container and heat to make it absolutely dry. To determine the absolute dry state, place a glass plate on the sample and judge that it is the absolute dry state when it is no longer cloudy due to moisture. Then, the flat container 2 and the heat dissipating metal fitting 7 were placed on a weighing machine, and the tare was corrected. Then, the sample B was put into the flat container 2 and the absolute dry weight m0 was measured. Absolute dry weight m0 = 925.3 g Set the flat container 2 and the heat dissipation metal fitting 7 in the high temperature aggregate cooling device 1, cool down to the temperature t1 = 28 ° C., and then store about 300 in the fixed quantity container.
After adding cc of water and placing it on a measuring instrument to perform tare correction, Sample B was put into a quantitative container and the weight m1 was measured. Dry weight m1 = 929.3 g The quantitative container was lowered from the measuring instrument and tare-corrected. Then, water of the same temperature was added to the quantitative container to make it full, the lid was covered, and the overflowing water was wiped to measure the total weight. Total weight T1 (= W1 + P) = 283.7 g (v) Calculation of absolute volume and water absorption amount (1a) Absolute volume and water absorption amount are determined as the amount of water reattached to the surface of the aggregate sample B as an increment Δh of surface water. It was Absolute volume s = V- (W1-m0) / c1 = 361.
9 cc Water absorption amount q = (W-m0)-(W1-m0) · c / c
1 = 17.1 g (vi) Calculation of absolute dry density, surface dry density, water absorption rate, surface water content and water content (1a) absolute dry density ρ0 = m0 / s = 2.557g surface 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% Moisture content Z = {(m-m0) / m0} * 100 = 8.
07%

[0041]

Example 2 The following procedure was used to measure the surface dry density, water absorption rate, and surface water rate of the aggregate based on the second method (volume method). (I) Sample C Sample C having a weight of m = 500 g is sampled by thoroughly mixing the wet fine aggregate which is uniformly and sufficiently absorbed with water. (Ii) Measuring container A Chapman flask as shown in FIG. 8A is used as the measuring container. The Chapman flask is gourd-shaped and has graduations in the central part (190-210) and the upper part (375-500). However, since there is an error in the graduation and the internal volume, calibration is performed in advance by the following procedure. First, after the Chapman flask is placed on a measuring instrument and the tare is corrected, water having a water temperature t is charged up to each scale to determine the weight u of the water, and the internal volume V is V = u /
Find with c. c is the density of water at the water temperature t. In the example, the water temperature is t = 21 ° C., and the water density is c = 0.997799 g / cc according to the science chronology. The result is shown in FIG.
Shown in.

(Iii) Measurement of absolute dry weight and absolute volume of sample C Sample C is put in a heat-resistant container and heated to an absolute dry state.
The absolute dry state was determined 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 the tare was corrected. Then, the sample C was put 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 dissipation fitting 7 were set in the high temperature aggregate cooling device 1 and cooled to a temperature t1 = 27 ° C. After cooling, the dry weight m1 was measured and found to be m1 = 466.3 g.
To the Chapman flask, 2 pieces of cooling water with a temperature of t1 = 27 ° C.
Add the scale of 01cc. With this, P0 = 20 from Table 1
It becomes 0 cc. Next, when the sample C was put into the Chapman flask and the scale was read, it was 395 cc.
Since the scale error at 00cc is -1.5, the volume sum P1 = 395-1.5 = 393.5cc, and the absolute volume s of the sample C is the absolute volume s = P1-P0 = 193.5cc (iv) Measurement of water absorption of sample C Attach an aspirator to the mouth of the Chapman flask and connect it to a vacuum pump. Roll the Chapman flask while reducing the pressure inside the Chapman flask to 0.3 atm, take out the air bubbles, and return to atmospheric pressure once again. Depressurization and this operation were repeated 3 times, 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 = 0.99651 g / cc according to the science chronology, the water absorption amount q = (P2-P1) c1 = (395-387) × 0.99965 = 7. 97g (v) Calculation of absolute dry density, surface dry density, water absorption rate, surface water content, water content Absolute dry density ρ0 = m0 / s = 2.410g Surface dry density ρ = (m0 + q) /s=2.451g Water absorption Rate Q = (q / m0) * 100 = 1.709% Surface water rate H = (m-m0-q) / (m0 + q)} * 1
00 = 5.43% Moisture content Z = {(m-m0) / m0} * 100 = 7.
23%

[0043]

As described in detail above, according to the present invention, aggregates A and B having the same weight m are collected from uniformly mixed wet aggregates,
Aggregate sample A was stored in a quantitative container of volume V and water was added to measure the total weight W in a full state, while aggregate sample B was heated to measure absolute dry weight m0 in an absolutely dry state. Then, the aggregate sample B is cooled to a room temperature range (dry weight m1 is measured),
Next, the aggregate sample B is stored in a fixed quantity container, water is added to measure the total weight W1 in a full state, and the absolute volume s and the water absorption amount q of the aggregate samples A and B are calculated from these measured values, Since the surface dry density, water absorption rate, and surface water rate of the aggregate sample are calculated, there is no need to create a surface dry sample, eliminating individual differences in measurement values, simplifying the measurement method, and shortening the measurement time. By doing so, it is possible to increase the number of measurements, and it is possible to obtain highly reliable measurement values by simultaneously obtaining the surface dry density, water absorption rate, and surface water rate from the measured wet aggregate, and the quality of the aggregate can be obtained. It is advantageous for management and formulation design.

According to the present invention, an aggregate sample C having a weight of m is sampled from the uniformly mixed wet aggregate, and the aggregate sample C is heated to measure the absolute dry weight m0 in an absolutely dry state. , The aggregate sample C is cooled, and after cooling, the aggregate sample C is accommodated in a measuring container containing water having a volume P0 sufficient to cover the aggregate sample C in advance and the total volume P1 of the sample and water is P1. Was measured, and then the pressure in the measuring container was reduced to remove the air bubbles generated in the container to allow the aggregate sample C to sufficiently absorb water, and then the volume sum P2 of the sample and water was measured. Since the absolute volume s and the water absorption amount q of the material sample C were calculated and the surface dry density, water absorption rate, and surface water rate of the aggregate sample were obtained, it is necessary to prepare the surface dry sample in the same manner as 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 highly reliable measurement values by simultaneously obtaining the surface dry density, water absorption rate, and surface water rate from the measured wet aggregate, which is useful for quality control and composition design of the aggregate. It is advantageous.

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

Further, the high temperature aggregate cooling device used for cooling the above-mentioned absolutely dry high temperature aggregate sample is a flat container having good thermal conductivity for accommodating the aggregate sample and the flat container. A cooling water tank filled with cooling water, a circulating water tank for receiving and storing cooling water overflowing from the cooling water tank, and a pump for circulating cooling water in the circulating water tank to the cooling water tank. With such a configuration, it is possible to cool a high temperature aggregate sample to a normal temperature region in a short time and to prepare cooling water (isothermal water) having the same temperature as the aggregate sample at the same time.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a measurement procedure according to a method of a first embodiment of the present invention.

FIG. 2A is a vertical cross-sectional view showing an embodiment of a fixed quantity container in which a lid is opened and FIG. 2B is closed.

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

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

FIG. 5 is a vertical cross-sectional view showing the high temperature aggregate cooling device of the embodiment of the present invention.

FIG. 6 is a perspective view of essential parts showing a disassembled state of the high-temperature aggregate cooling device of the embodiment of the present invention.

FIG. 7 is a diagram showing an outline of 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 result.

FIG. 9 is a diagram schematically showing a state change of an aggregate sample in the method of 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 cases 7 Heat sink 11 fixed quantity container 12 Lid 21 weighing container 22 Aspirator

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Claims (5)

(57) [Claims] 1. Aggregate samples A and B having the same weight m are collected from uniformly mixed wet aggregates, and the aggregate sample A is stored in a quantitative container having a volume V and water is added to make a total weight W. On the other hand, the aggregate sample B is heated to measure the absolute dry weight m0 in an absolutely dry state, then the aggregate sample B is cooled, and after cooling, the aggregate sample B is placed in a quantitative container. Absolute volume s of the aggregate samples A and B is measured by measuring the total weight W1 in a state of being filled with water and filled with water.
And the water absorption amount q is calculated from the following formula: Absolute volume s = V- (W1-m0) / c1 Water absorption amount q = (W-m0)-(W1-m0) c / c1 where c and c1 are total weights Density of water hydrated when measuring W and W1 Measurement of surface dry density, water absorption rate and surface water rate of aggregate characterized by obtaining surface dry density, water absorption rate and surface water rate of aggregate sample 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 stored in a quantitative container having a volume of V and water is added to make a total weight W. On the other hand, the aggregate sample B is heated to measure an absolute dry weight m0 in an absolutely dry state, and then the aggregate sample B is cooled to a normal temperature range to measure a dry weight m1. The aggregate sample B is placed in a fixed quantity container, water is added, and the total weight W1 is measured in a full state,
The absolute volume s and the water absorption amount q of the above aggregate samples A and B are obtained from the following equations: Absolute volume s = V- (W1-m1) / c1 Water absorption amount q = (W-m0)-(W1-m1) c / C1 where c and c1 are the densities of water added when measuring the total weights W and W1, respectively, and the surface dry density, water absorption rate, and surface water rate of the aggregate sample are obtained from the table. Methods for measuring dry density, water absorption and surface water. 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 accommodated in a measuring container containing 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, Next, after decompressing the inside of the measuring container to remove bubbles generated in the container and allowing the aggregate sample C to sufficiently absorb water, the volume sum P2 of the sample and water is measured, and the aggregate sample C is measured.
The absolute volume s and the water absorption amount q of are calculated from the following formulas: Absolute volume s = P1-P0 Water absorption amount 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 rate, and surface water rate of an aggregate, which comprises determining the surface dry density, water absorption rate, and surface water rate of the aggregate sample. 4. When cooling a high temperature aggregate sample in an absolutely dry state, the container containing the aggregate sample is immersed in a cooling water tank filled with cooling water to obtain the temperature of the aggregate sample and the cooling water. After cooling the aggregate sample until the values are equal, cooling water having the same temperature is used to measure the full weight W1 of the aggregate sample and water or the volume sum P1 and P2 of the aggregate sample and water. Dry density, water absorption rate of the aggregate according to claim 1, 2 or 3,
Method of measuring surface water ratio. 5. A flat container having high thermal conductivity for containing 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 controlling the circulating water, and a pump for pumping the cooling water in the circulating water tank to the cooling water tank are provided.
A high-temperature aggregate cooling device used in the described measuring method.