JPH0425744A - Test method for strength of aggregate - Google Patents

Abstract

PURPOSE:To accurately decide strength of aggregate in an early stage before producing concrete by kneading aggregate with thermosetting resin and introducing a filler at this time to form a speciment and performing compression test therefor. CONSTITUTION:As thermosetting resin, polyester-based, acryl-based and epoxy- based resin are utilized. As a filler, calcium carbonate and stone dust, etc., are utilized. In accordance with necessity, a hardening agent and a hardening accelator are added at a time for kneading and hardening time is controlled. Thereby strength test is performed in a state wherein aggregate is stuck to concrete. Strength of aggregate due to combination of fine aggregate and coarse aggregate is accurately decided. Moreover since a specimen is manufactured in a short time, the test time is drastically shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for testing aggregate strength in, for example, ultra-high strength concrete.

(Prior art) Conventionally, for example, the compressive strength testing method for aggregate in ultra-high strength concrete has been carried out by placing the aggregate in a container and applying pressure directly to the aggregate using a pressurizing body, or by applying pressure to the aggregate using a pressurizing body. A falling impact was applied to the aggregate to crush it, and the strength of the aggregate was measured from this crushing condition.

(Problem to be solved by the invention) The problem with the above test method is that since the pressure applied to the aggregate is contact pressure, the adhesion strength with concrete is not taken into account, and the particle size distribution differs from that actually used. Therefore, it does not represent the strength of aggregate in concrete. In reality, the compressive strength of ultra-high strength concrete is tested four weeks after concrete production to confirm quality control.

An object of the present invention is to enable early and accurate determination of aggregate strength before concrete production.

(Means for Solving the Problems) In this invention, a test is conducted under conditions similar to those of cement concrete. For this purpose, thermosetting resin and aggregate are kneaded, a filler is added during the second kneading process, a test piece is formed, and this test piece is subjected to a compression test.

Thermosetting resins include polyester resins, acrylic resins, epoxy resins, and the like. Examples of the filler include calcium carbonate and stone powder. In order to accelerate the curing of the thermosetting resin, a curing agent or a curing accelerator is added during kneading as necessary to control the curing time of the test specimen. Furthermore, by using thermosetting resins with different strength characteristics, it is possible to rank aggregate strengths from high strength to ultra-high strength.

(Effects of the Invention) According to the present invention, strength tests can be performed with aggregates attached to concrete, the strength of aggregates can be determined accurately by a combination of fine aggregates and coarse aggregates, and the test can be performed in a short time. Since the body can be created, strength tests can be performed at an early stage, significantly shortening the conventional test time.

(Experiment example) A polyester resin concrete test specimen was created and a compression test was conducted.

Polyester resin is used as the liquid resin as the binder, the following is used as the aggregate, calcium carbonate is selected as the filler, the filler is kneaded with the binder, and a hardening accelerating admixture is added. The sample was placed in a mold, heated, and a test specimen was completed 2 to 3 hours later. A compression test was conducted 2 to 3 hours after completion, and the results shown in Table 1 were obtained.

Aggregate Coarse aggregate...crushed stone (hard sandstone), crushed stone (limestone), crushed stone (andesite), river gravel, fine aggregate...crushed sand (hard sandstone), crushed sand (limestone), mountain sand, river sand, From this Table 1, the variation range of compressive strength is 811 to 107
2 kg f / cm 2, and the weakest aggregate strength is Kinugawa for coarse aggregate and Kashima for fine aggregate.In particular, the influence of concrete compressive strength on coarse aggregate strength is big.

In addition, attached Table 2 shows the 4-week compressive strength of cement concrete. The materials used were ordinary Portland cement, and the aggregates and admixtures were the same as in the case of the polyester resin cement test specimen.

From this Table 2, the variation range of compressive strength is 874 to 112
1 kg f / cm 2, and the weakest aggregate strength is Kinugawa for coarse aggregate and Kisarazu for fine aggregate, and the influence of concrete compressive strength on coarse aggregate strength is particularly large. .

Attached Table 3 shows the relationship in compressive strength between polyester resin concrete and cement concrete. As can be determined from Table 3, there is a correlation between polyester resin concrete and cement concrete, and by using polyester resin concrete, the strength of the aggregate of ultra-high-grade concrete could be determined in one day.

Patent applicant Hase Corporation Co., Ltd.

Claims (1)

[Claims] An aggregate strength testing method characterized by kneading a thermosetting resin and aggregate, adding a filler during the kneading to form a test specimen, and measuring the strength of the aggregate by compressing the test specimen. .