JP4932679B2 - Method for calculating specifications of fine aggregate - Google Patents

Description

  The present invention does not require a surface dry state determination operation, and therefore there is no difference between trial users, and it is possible to determine and calculate the fine aggregate specification values simply and quantitatively. The present invention relates to a specification value calculation method.

  Various methods for measuring the surface dry density of fine aggregates as known quantities are known as methods for measuring concrete materials (see Patent Documents 1 to 4). The measurement of the surface dry density of the fine aggregate has been conventionally performed in accordance with “Test method for density and water absorption rate of fine aggregate” (JIS A 1109).

The test method is roughly performed as follows. First, the sample is brought into a surface dry saturated state (surface dry). In order to make the surface dry, the sample is allowed to absorb water for 24 hours, and then spread thinly on a flat surface and gradually dried. Then, when there is still a little surface water on the surface of the sample, the sample is loosely packed into the flow cone, the upper surface is leveled, and lightly struck 25 times with a stick, and then the flow cone is pulled up vertically. When the flow cone is pulled up, the first time the sample slumps like a landslide is determined to be in the surface dry state. This process is repeated while the sample is slowly drying until it is slumped.
Japanese Patent No. 3525802 Japanese Patent Laid-Open No. 2002-234025 JP 2002-248617 A JP 2002-257817 A

  In the conventional test method, there is a problem that the sample needs to be in a surface dry state, which requires considerable time and labor. In addition, since determination of the surface dry state is not a quantitative method, there is a problem in that there may be a difference in determination of the surface dry state depending on a person who tries. In particular, in the case of crushed sand having a large amount of fine particles, it is difficult to dry the fine particles, and it is difficult to determine the surface dry state because the sample is difficult to dry uniformly. In the case of recycled fine aggregates, mortar grains are also mixed, and similarly, it is difficult to uniformly dry the sample, and it is difficult to determine the surface dry state.

  As described above, the determination of the surface dry state varies, resulting in a difference in the fine aggregate density and the water absorption value. If the surface water ratio and the like are calculated using such density and the like, the results vary. Ultimately, if an uncertain surface water percentage of fine aggregate is applied, it cannot be kneaded with an appropriate amount of kneading water, which will affect the concrete quality.

  The present invention has been devised in view of the above-described conventional problems, and does not require the determination of the surface dry state. Therefore, there is no difference between trial users, and the specifications of the fine aggregate can be simply and quantitatively. An object of the present invention is to provide a specification value calculation method for fine aggregate that can determine and calculate a value.

The fine aggregate specification value calculation method according to the present invention uses a fine aggregate having the same mass W ₀ in a wet state as a first sample and a second sample, and the first sample and the second sample have different densities ρ. ₁ and ρ ₂ are immersed in the first liquid and the second liquid, respectively, to determine the mass W _S1 of the first sample in the first liquid and the mass W _S2 of the second sample in the second liquid, respectively. Then, the following formula

V _S = (W _S1 −W _S2 ) / (ρ ₂ −ρ ₁ )
W _S = W _S1 + ρ ₁ × V _S
ρ _s = W _S / V _S
H = W _F / W _S × 100 (W _F = W ₀ −W _S : surface water amount)

Then, the volume V _S , mass W _S , density ρ _s , and surface water ratio H of the fine aggregate in the surface dry state are calculated.

A fine aggregate with a mass W ₀ in a wet state is used as a third sample, and the mass m ₀ of the absolutely dry state of the third sample is measured.

Q _S = [(W _S −m ₀ ) / m ₀ ] × 100

And calculating the water absorption rate Q _S of the fine aggregate.

  The first liquid is water, and the first sample is completely dried and used as the third sample.

Two first and second sample containers for individually containing a first sample and a second sample, and two first and second weighing containers for individually containing a first liquid and a second liquid, respectively First, each sample container is immersed in each measuring container, and the mass W _C1 of the first sample container in the first liquid and the second sample container W _C2 in the second liquid are prepared. The mass was weighed, and then each of the first sample and the second sample was placed in each sample container, each sample container was immersed in each measurement container, and the first sample in the first liquid was placed. the mass W ₂ of the second sample container containing the second sample of the first mass W ₁ and the second liquid in the sample container were weighed respectively, then the following formula

W _S1 = W ₁ −W _C1
W _S2 = W ₂ −W _C2

Then, the mass W _S1 of the first sample in the first liquid and the mass W _S2 of the second sample in the second liquid are respectively determined.

  In the method for calculating the specification value of the fine aggregate according to the present invention, the determination operation of the surface dry state is unnecessary, and therefore there is no difference between the trial persons, and the specification of the fine aggregate is simple and quantitative. The value can be determined and calculated.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a fine aggregate specification value calculating method according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a flowchart of a fine aggregate specification value calculation method according to this embodiment. FIG. 2 shows a state in which a weighing operation is performed using a sample container and a weighing container.

  First, in step 1, the fine aggregate that is the target of the specification value calculation is set in a wet state. In general, as shown in FIG. 3, the water content of the aggregate includes a furnace dry state (absolute dry) in which the aggregate is not impregnated with water at all, and an air dry state (air) in which the aggregate is impregnated with water. Dry), surface dry saturated water in which the aggregate is impregnated in the saturated state (surface dry), and water adheres as surface water even partially on the aggregate surface beyond the surface dry stage. It is classified as a wet state. The water content of the aggregate is obtained by adding the surface water amount to the amount of water absorbed by the aggregate and impregnated therein. With respect to the water absorption amount, the water absorption amount in the air dry state is referred to as the air dry water content, and the water absorption amount in the surface dry state is referred to as the effective water absorption amount based on the absolutely dry state.

In this embodiment, the fine aggregate is in a wet state in which surface water is adhered beyond the surface dry state. The target fine aggregate may be any material such as crushed sand and recycled fine aggregate, in addition to normal sand. Then, the fine aggregate in a wet state is weighed to prepare two first and second samples having the same mass W ₀ .

Next, in Step 2, a first liquid and a second liquid having different densities ρ ₁ and ρ ₂ are prepared. These liquids only need to have different densities. For example, the liquid may be appropriately selected such that the first liquid is water and the second liquid is saline. In addition, for example, two bucket-like first sample containers 1a and second sample containers 2a, and first and second liquids, for example, each of which has a bucket-like shape, are used to individually store the first sample and the second sample. For example, two bucket-like first weighing containers 1b and a second weighing container 2b are prepared for individual entry. The measuring containers 1b and 2b are larger than the sample containers 1a and 2a so that the sample containers 1a and 2a can be immersed therein. These weighing containers 1b and 2b need not have the same capacity. The first liquid and the second liquid are put into the first weighing container 1b and the second weighing container 2b, respectively.

Next, in step 3, the first sample container 1a is immersed in the first weighing container 1b. Once immersed, the mass W _C1 of the first sample container 1a in the first liquid is weighed. In the figure, 4 is a scale. Similarly, the second sample container 2a is immersed in the second measuring container 2b, and when immersed, the mass W _C2 of the second sample container 2a in the second liquid is measured. For the degree of immersion, the entire sample containers 1a and 2a are completely submerged in the measuring containers 1b and 2b. As shown in the figure, when measuring, when the state is hung with the hanger 3 or the like, it is desirable to mark the position of the hanger 3 immersed in the liquid. Thereby, the accuracy of the final calculation result can be increased.

  Next, in step 4, each sample container 1a, 2a is taken out from each weighing container 1b, 2b. At this time, the liquid may remain in the sample containers 1a and 2a. The first sample is put into the first sample container 1a and the second sample is put into the second sample container 2a, respectively.

  Next, in step 5, a part of the first liquid is transferred from the first measuring container 1b into the first sample container 1a. Further, a part of the second liquid is transferred from the second measuring container 2b into the second sample container 2a. By putting the liquid in the sample containers 1a and 2a containing the sample, the fine powder contained in the fine aggregate is confined in the sample containers 1a and 2a. Thereby, the dispersion of fine particles can be prevented, and the state of the fine aggregate used as a sample can be faithfully reproduced. Each sample is stirred in each solution in each sample container 1a, 2a. As a result, air that adversely affects the weighing operation is expelled from the sample containers 1a and 2a as bubbles. After stirring, leave it quiet for a while.

Next, in Step 6, the first sample container 1a containing the first sample immersed in the first liquid is immersed in the first measuring container 1b containing the first liquid. When immersed, the mass W ₁ of the first sample container 1a containing the first sample in the first liquid is weighed. Similarly, the second sample container 1b containing the second sample in a state immersed in the second liquid is immersed in the second measuring container 2b containing the second liquid, and the second sample container 1b The mass W ₂ of the second sample container 2a containing the second sample in the liquid is weighed.

  It is desirable that the degree of immersion is equivalent to the state in which each sample container 1a, 2a is submerged in each weighing container 1b, 2b. When marking is performed, the immersion operation may be performed with reference to the marking.

Next, in step 7, the masses W _C1 and W _C2 of the individual sample containers 1a and 2a in the first liquid and the second liquid obtained by the above operation, and the first and second in each liquid, respectively. Using the masses W ₁ and W ₂ of the first and second sample containers 1a and 2a containing the samples,

W _S1 = W ₁ −W _C1
W _S2 = W ₂ −W _C2

The mass W _{S1 of} only the first sample in the first liquid and the mass W of only the second sample in the second liquid, excluding the masses W _C1 and W _C2 of the sample containers 1a and 2a. Determine _S2 respectively.

Next, using these masses W _S1 and W _S2 and the densities ρ ₁ and ρ ₂ of the first and second liquids, the following relational expression between the volume V _S and the mass W _S of these samples in the surface dry state

W _S1 = W _S −ρ ₁ × V _S
W _S2 = W _S −ρ ₂ × V _S

From the following formula, which is obtained by arranging by the volume V _S of the surface dry sample

V _S = (W _S1 −W _S2 ) / (ρ ₂ −ρ ₁ )
W _S = W _S1 + ρ ₁ × V _S
ρ _s = W _S / V _S
H = W _F / W _S × 100 (W _F = W ₀ −W _S : surface water amount)

Then, the volume V _S , mass W _S , density ρ _s , and surface water ratio H in the surface dry state of the fine aggregate as a sample are calculated.

For surface water ratio H in the above formula, the mass W ₀ of fine aggregate in a wet state was prepared as a sample, the surface water W _F from the difference between the mass W _S of fine aggregate-dry state is calculated By determining, it can be calculated.

Next, calculation of the water absorption rate Q _S of the fine aggregate will be described. The fine aggregate in the wet state in which Sample 1 and Sample 2 are prepared is weighed to prepare a third sample having the same mass W ₀ as shown in Step 8 in FIG.

Next, in step 9, the third sample is brought into an absolutely dry state called a furnace dry state by a known method such as heating, and its mass m ₀ is measured.

Next, in step 10, using the mass m ₀ in the absolutely dry state of the third sample and the mass W _S in the surface dry state of the first and second samples calculated in step 7,

Q _S = [(W _S −m ₀ ) / m ₀ ] × 100 (%)

Then, the water absorption rate Q _S of the fine aggregate as a sample is calculated.

  As the third sample, for example, when the first liquid is water, the first sample can be used as it is by making it completely dry. In addition to the first and second samples, the third sample is separately provided. Can save you the trouble of preparing.

  In the fine aggregate specification value calculation method according to the present embodiment described above, the fine aggregate in the wet state is handled and the specification value of the fine aggregate in the dry state is calculated. Therefore, there is no need to put the fine aggregate in a dry state as in the background art, and the time and labor required for this can be saved. Further, in the background art, the determination of the surface dry state is not quantitative, and there is a possibility that the determination may vary depending on the touch of the person who performs the trial. However, in the calculation method according to this embodiment, an objective measurement operation is performed. Using this result, it is possible to quantitatively calculate the specifications of fine aggregates in the surface dry state, so there is no need for the determination of the surface dry state, and therefore there is no difference between trial users. Any fine aggregate such as recycled fine aggregate and fine aggregate containing fine particles can be used to determine the specification value of the fine aggregate appropriately and with high accuracy. In addition, since only the weighing operation is mainly performed, the operation can be easily performed.

Furthermore, if the mass W _{S1 of} only the first sample in the first liquid and the mass W _S2 of only the second sample in the second liquid are determined, the volume V _S and mass W of the fine aggregate in the surface dry state are determined. _S , density ρ _s , and surface water ratio H can be determined at once in a short time. If the specification value of the fine aggregate obtained by the calculation method according to the present embodiment is used, kneading can be performed with an appropriate amount of kneading water, and the concrete quality can be improved.

  Moreover, in this embodiment, the fine powder contained in the fine aggregate can be confined in the sample containers 1a and 2a by putting the liquid in the sample containers 1a and 2a containing the sample, As a result, the dispersion of fine particles can be prevented, and a calculation result that faithfully reproduces the state of the fine aggregate used as a sample can be obtained. Furthermore, since each sample is stirred in each liquid in each sample container 1a, 2a, air that adversely affects the weighing operation can be expelled from the sample containers 1a, 2a as bubbles, Also from this aspect, the specification value of the fine aggregate can be calculated with high accuracy.

  In step 6 described in the above embodiment, in order to immerse the sample containers 1a and 2a containing the respective samples into the respective measurement containers 1b and 2b containing the respective liquids, the sample containers are previously stored in step 5. The liquid is put in 1a and 2a. However, it is not always necessary to put the liquid in the sample containers 1a and 2a in advance, and only the sample may be put in the sample containers 1a and 2a and immersed in the weighing containers 1b and 2b. . Preliminarily putting the liquid in the sample containers 1a, 2a can prevent fine particles from escaping into the measurement containers 1b, 2b when immersed in the measurement containers 1b, 2b. The agitation operation described above can be performed to expel air as bubbles in advance.

Further, in the present embodiment, the case of measuring the mass using the sample containers 1a and 2a and the measuring containers 1b and 2b has been described as an example. Of course, these containers 1a, 1b, 2a, 2b need not be used as long as the masses W _S1 , W _S2 of the samples can be measured or determined.

It is a flowchart figure which shows suitable one Embodiment of the specification value calculation method of the fine aggregate concerning this invention. It is explanatory drawing which shows a mode that measurement operation is performed using the container for a sample and the container for a measurement with the calculation method shown in FIG. It is explanatory drawing explaining the general classification | category of the moisture content state of an aggregate.

Explanation of symbols

1a, 2a Sample container 1b, 2b Measuring container

Claims (4)

A fine aggregate having the same mass W ₀ in a wet state is used as a first sample and a second sample,
The first sample and the second sample are immersed in the first liquid and the second liquid having different densities ρ ₁ and ρ ₂ , respectively, so that the mass W _S1 and the second liquid of the first sample in the first liquid are absorbed. Determine the mass W _S2 of the second sample in each,
Then the following formula

V _S = (W _S1 −W _S2 ) / (ρ ₂ −ρ ₁ )
W _S = W _S1 + ρ ₁ × V _S
ρ _s = W _S / V _S
H = W _F / W _S × 100 (W _F = W ₀ −W _S : surface water amount)

Then, the volume value V _S , mass W _S , density ρ _s , and surface water ratio H in the surface dry state of the fine aggregate are calculated. A fine aggregate with a mass W ₀ in a wet state is used as the third sample, and the mass m ₀ of the absolutely dry state of the third sample is measured.
Following formula

Q _S = [(W _S −m ₀ ) / m ₀ ] × 100

2. The specification value calculation method for fine aggregate according to claim 1, wherein the water absorption rate Q _S of the fine aggregate is calculated.   3. The specification value calculation method for fine aggregates according to claim 2, wherein the first liquid is water, and the first sample is used in the third sample after being completely dried. Two first and second sample containers for individually containing a first sample and a second sample, and two first and second weighing containers for individually containing a first liquid and a second liquid, respectively Prepare
First, each sample container is immersed in each weighing container, and the mass of the first sample container W _{C1 in} the first liquid and the mass of the second sample container W _C2 in the second liquid are measured. And
Next, each of the first sample and the second sample is put in each sample container, each sample container is immersed in each measurement container, and the first sample container in which the first sample in the first liquid is put. The mass W ₁ of the second sample container and the mass W ₂ of the second sample container containing the second sample in the second liquid,
Then the following formula

W _S1 = W ₁ −W _C1
W _S2 = W ₂ −W _C2

And determining the mass W _S1 of the first sample in the first liquid and the mass W _S2 of the second sample in the second liquid, respectively. 2. Method for calculating specification values of fine aggregates as described in 1.

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