JP4501312B2 - Method for judging the quality of aggregate for concrete - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for judging the quality of an aggregate kneaded in concrete.
[0002]
[Prior art]
The quality of concrete depends on the characteristics of the individual constituent materials used. Cement and various admixtures, which are constituent materials of concrete, are guaranteed at a certain quality because they are usually produced at the factory.
[0003]
Further, when tap water is used as the water for kneading, the same quality can be obtained. However, the aggregate composed of the fine aggregate and the coarse aggregate in the constituent material of the concrete occupies about 70% of the total volume in the concrete, which greatly affects the quality of the concrete.
[0004]
Further, it is known that such aggregates have different densities, shapes, particle sizes, etc., and the quality of the concrete produced is different even when used in the same composition.
[0005]
Therefore, conventionally, the quality of component materials such as cement, fine powder of blast furnace slag, fly ash, fine powder of limestone, fine aggregates, coarse aggregates, etc. are individually tested, and each has its own physical properties. Information is obtained, and then these are kneaded and test kneaded so that the concrete has the required quality, and the quality of the concrete is confirmed by this test kneading.
[0006]
However, such a method for checking the quality of concrete has the following problems.
[0007]
[Problems to be solved by the invention]
In other words, in the conventional method for confirming the quality of concrete, cement and admixture are generally produced at the factory and the quality is stable. However, the aggregate is usually a natural product and the quality varies. In other words, this is the biggest factor that requires testing at each ready-mixed concrete manufacturing plant.
[0008]
At the same time, the interaction when mixing fine and coarse aggregates also affects the quality of the concrete, so testing was essential.
[0009]
However, the method of confirming the quality by test kneading takes time and labor, and the composition design is performed in an inefficient state.
[0010]
The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a method for determining the quality of a concrete aggregate that enables efficient blending design. is there.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an aggregate quality judgment method comprising a fine aggregate and a coarse aggregate used when producing concrete by mixing cement and various admixtures. The material and the coarse aggregate are mixed, the actual volume ratio of these mixtures is measured, and based on the obtained actual volume ratio, the quality related to the consistency when these are kneaded with the concrete is judged. I did it.
[0012]
In the method for judging the quality of the aggregate for concrete as described above, among the solid materials constituting the concrete, fine aggregate and coarse aggregate which are chemically unreacted materials are mixed, and the actual product of these mixtures is mixed. The ratio is measured, and based on the obtained actual volume ratio, the quality related to the consistency when these are kneaded with concrete is judged.
[0013]
Here, the actual volume ratio is a ratio of the space occupied by the mixture in the space in the container when the fine aggregate and the coarse aggregate are mixed and filled in the predetermined container, When the actual volume ratio is high, there is a relation that the consistency when kneaded into concrete is large and soft, and when the actual performance ratio is low, it becomes hard.
[0014]
In the present invention, based on the relationship between the actual volume ratio and the consistency, the actual volume ratio is measured before the aggregate is kneaded, and the consistency when kneaded into the concrete based on the actual volume ratio. Judgment on quality related to tensi.
[0015]
In addition, according to the aggregate quality judgment method, the interaction between fine aggregate and coarse aggregate that affects the quality of concrete is evaluated in advance as an actual volume ratio by mixing these. As the quality of the aggregate used for the test kneading, the fine aggregate and coarse aggregate are evaluated together, thereby improving the efficiency of the compounding design.
[0016]
In addition, the actual volume ratio of the aggregate of the predetermined ratio and concrete in which the aggregate of the same ratio is actually kneaded are prepared, and the concrete consistency is obtained by, for example, slumping the concrete. If the correlation is obtained in advance and the correlation is calibrated using graphs, etc., when producing concrete with the same consistency, different types of aggregates are made with the same ratio of the other constituent materials. Even when using, concrete with the same consistency can be obtained by selecting an aggregate with the same actual volume ratio.
[0017]
In the quality determination method of the present invention, water is added and kneaded so as to increase the mixture stepwise, the mixer load at the time of kneading is measured, and the concrete is kneaded based on the mixer load. It is possible to judge the quality related to the consistency.
[0018]
When such a configuration is adopted, a mixture of fine aggregate and coarse aggregate does not cause a chemical reaction even when water is added, as in the case where cement is added. Therefore, the behavior of the mixture with respect to the amount of water added can be accurately grasped.
[0019]
In addition, when such a configuration is adopted, information such as the amount of water required to obtain a predetermined consistency and the sensitivity to fluctuations in the amount of water can be obtained based on the relationship between the amount of water added and the mixer load.
[0020]
Furthermore, in the present invention, inactive powder having the same physical properties as the cement can be added to the concrete instead of the cement.
[0021]
When this configuration is adopted, a non-active powder instead of cement is used as a calibration powder, and this is added to produce concrete, the consistency of which is investigated, and compared with the consistency when cement is used. By doing so, it is possible to evaluate the influence of the used powder on the consistency.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a position example of a method for determining the quality of a concrete aggregate according to the present invention.
[0023]
1 and 2 show an embodiment of a method for determining the quality of concrete aggregate according to the present invention. The quality determination method of the present invention is applied to the determination of the quality of an aggregate used when manufacturing concrete by kneading cement and various admixtures, that is, the fine aggregate s and the coarse aggregate S. Is.
[0024]
When determining the quality of these aggregates, first, fine aggregates s and coarse aggregates S having a dry surface with a predetermined blending ratio are prepared, and these fine aggregates s and coarse aggregates S are prepared. The actual volume ratio V1 is measured in such a manner that these are mixed.
[0025]
The measurement of the actual volume ratio V1 is performed in accordance with JIS A1104-1999 “Measurement Method of Aggregate Unit Volume Mass and Actual Volume Ratio”. The actual volume ratio V1 measured here is substantially filled with a mixture M1 (a mixture of fine aggregate s and coarse aggregate S) in a container 10 having a known internal volume V0. In this case, the ratio of the mixture M1 in the space in the container 10 is close to the actual volume ratio V1 and the consistency when the aggregate having the volume ratio is mixed with concrete. Relevance is recognized.
[0026]
Such a measurement of the actual volume ratio is performed by appropriately changing the blending ratio of the fine aggregate s and the coarse aggregate S to create a plurality of types of mixtures M1 to Mn. The respective actual product ratios V1 to Vn are obtained for a plurality of types of mixtures M1 to Mn having different blending ratios.
[0027]
The actual volume ratios V1 to Vn obtained in this way are used as criteria for judging the quality related to the consistency when these are kneaded into concrete based on the values.
[0028]
When the actual volume ratios V1 to Vn obtained in this example are high, the consistency when kneaded into concrete is large and soft, and the actual ratios V1 to Vn are low. It is related to becoming hard.
[0029]
In this example, based on the relationship between the actual volume ratios V1 to Vn and the consistency, the actual volume ratios V1 to Vn are measured before the fine aggregate s and the coarse aggregate S are kneaded, Based on the actual volume ratios V1 to Vn, the quality related to the consistency when kneaded with concrete is determined.
[0030]
Further, according to such an aggregate quality judgment method, the interaction between the fine aggregate s and the coarse aggregate S affecting the quality of the concrete can be evaluated in advance, so that it is used for test mixing. As the quality of the aggregate, the fine aggregate s and the coarse aggregate S are evaluated together, thereby improving the efficiency of the blending design.
[0031]
In addition, the relationship between the actual volume ratios V1 to Vn of the fine aggregate s and the coarse aggregate S of a predetermined ratio and the consistency of the concrete in which the aggregate of the same ratio is kneaded is obtained in advance and calibrated with a graph or the like. Therefore, when producing concrete with the same consistency, other structural materials should be used in the same ratio, even if they are different types of aggregates, aggregates with the same actual volume ratios V1 to Vn can be used. For example, concrete with the same consistency can be obtained.
[0032]
In the case of the present embodiment, when the above measurement of the actual volume ratios V1 to Vn is completed, next, for each of the mixtures M1 to Mn at each mixing ratio, as shown in FIG. The mixer load is measured when the agitating mixer 12 is inserted and water W is added and kneaded.
[0033]
The mixer load is measured by measuring the supply current I of the rotation drive motor 14 of the stirring mixer 12, and an ammeter 16 for measuring the supply current I is provided between the power source 18 and the drive motor 14. Inserted and connected.
[0034]
In addition, the measurement of the mixer load by the supply current I is performed by adding water W to the mixtures M1 to Mn accommodated in the container 10, and at this time, the amount of water W added is increased stepwise. While doing.
[0035]
FIG. 2 is a graph showing an example of the mixer load measured by such a method. In the figure, the horizontal column is the amount of water W added, and the vertical column is the value of the mixer load (supply current I).
[0036]
When such a mixer load (supply current I) is obtained, the result is used to judge the quality related to the consistency when the aggregates (fine aggregate s and coarse aggregate S) are mixed with concrete.
[0037]
Based on such a mixer load (supply current I), when the quality of the consistency when kneaded into concrete is determined, the mixtures M1 to Mn obtained by mixing the fine aggregate s and the coarse aggregate S are cement. Since no reaction occurs even when water is added as in the case where water is added, it is possible to add water W in stages, and accurately grasp the behavior of the mixtures M1 to Mn relative to the amount of water W added. As a result, it is possible to accurately judge quality.
[0038]
In addition, when such a configuration is adopted, information such as the amount of water required to obtain a predetermined consistency and the sensitivity to fluctuations in the amount of water can be obtained from the relationship between the amount of water W added and the mixer load.
[0039]
Although not described in the above embodiment, in the present invention, when evaluating the consistency of concrete in advance, instead of cement, inactive powder having the same physical properties as the cement is used. Can be added.
[0040]
In this way, non-active powder instead of cement is used as calibration powder, and this is added to produce concrete, and its consistency is examined and compared with the consistency when cement is used. Thus, it is possible to evaluate the influence of consistency due to the powder used.
[0041]
【The invention's effect】
As described above in detail, according to the concrete aggregate quality determination method according to the present invention, an efficient blending design is possible.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing one embodiment of a method for determining the quality of concrete aggregate according to the present invention.
FIG. 2 is a graph showing the relationship between the mixer load and the amount of added water obtained by the determination method of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Container 12 Stirring mixer 14 Drive motor 16 Ammeter s Fine aggregate S Coarse aggregate

Claims (3)

In the method of judging the quality of aggregate consisting of fine aggregate and coarse aggregate used when preparing concrete by mixing with cement and various admixtures,
The fine aggregate and the coarse aggregate are mixed, the actual volume ratio of these mixtures is measured, and based on the obtained actual volume ratio, the quality related to the consistency when these are kneaded with the concrete A method for judging the quality of a concrete aggregate characterized by judging. Water is added to the mixture in a stepwise manner and kneaded, and the mixer load at the time of kneading is measured. Based on the mixer load, the quality related to the consistency when kneaded into the concrete is determined. The quality judgment method for concrete aggregate according to claim 1, wherein the quality is judged. The method for judging the quality of aggregates for concrete according to claim 1 or 2, wherein inactive powder having the same physical properties as the cement is added to the concrete instead of the cement.

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