Device and method for testing volume compression ratio of lightweight aggregate concrete mixture

Abstract

The invention discloses a device and a method for testing the volume compression ratio of a lightweight aggregate concrete mixture. The device comprises a concrete pressure bleeding instrument, a pressure pump and a telescopic rod. The concrete pressure bleeding instrument comprises a jack, a piston and a cylinder body, the piston is arranged in the cylinder body, the lower end of the jack is connected with the upper end of the piston, and the telescopic rod is vertically arranged on a base in the cylinder body, and the pressure pump is connected with the jack. The volume compression ratio ofthe lightweight aggregate concrete mixture can be simply, conveniently and quickly tested, so that the pumping performance change of the lightweight aggregate concrete mixture under the pressure can be predicted. The device and the method are used for evaluating the water absorption behavior of the lightweight aggregate in the lightweight aggregate concrete mixture under the action of pressure, soas to predict and evaluate the pumping stability of the lightweight aggregate concrete under the action of the super high-rise pumping pressure.

Description

technical field [0001] The invention relates to the technical field of concrete measurement, in particular to a testing device and method for volumetric compressibility of lightweight aggregate concrete mixture. Background technique [0002] Lightweight aggregate concrete has the characteristics of high specific strength, good durability and thermal insulation performance, excellent seismic performance, and no risk of alkali-aggregate reaction. Studies have shown that the weight of building structures using lightweight aggregate concrete is about 20% lower than ordinary concrete. , using it in super high-rise buildings can reduce the structural weight. For super high-rise buildings, the corresponding structural size can be appropriately reduced, and the utilization rate of the standard floor area can be improved; at the same time, the seismic performance and durability of the building can be improved, and the thermal insulation and insulation of the building can be improved. ...

AI Technical Summary

Problems solved by technology

[0003] In super high-rise building construction, pumping construction has technical and economic advantages unmatched by other construction methods. However, the use of lightweight aggregate concrete in super high-rise building pumping construction still has the following problems: ①The effect of water absorption under the pressure of light aggregate on the The performance of lightweight aggregate concrete mixture is greatly affected. Lightweight aggregate is a porous material, and there are many open pores on its surface, which absorbs a large amount of water, which will easily lead to a rapid loss of working performance of lightweight aggregate concrete mixture, resulting in Pumping is difficult; ②The water absorption behavior of lightweight aggregates has a greater impact on the mixture during super-high-rise pumping construction. Due to the ultra-high pumping pressure, the water absorption effect of lightweight aggregates will be further amplified, resulting in The working performance drops sharply, and when the lightweight aggregate concrete is pumped to the working surface, due to the reduction of the environmental pressure, this part of the newly absorbed water will be released again to cause "secondary water release", which affects the workability of the mixture and the later performance of the structure , it can be said that the water absorption behavior of lightweight aggregate under pressure plays a decisive role in the ultra-high pumping construction of lightweight aggregate concrete; It is carried out under normal pressure conditions. Once the pressure is released, the water absorption behavior of lightweight aggregate will change, and the lightweight aggregate concrete mixture is prone to delamination. It is not suitable to directly test the mixture. The "secondary water release" phenomenon of aggregates will have a great impact on the test results. The existing testing and evaluation methods for concrete mixtures cannot systematically, comprehensively and accurately quantify the impact of water absorption behavior of lightweight aggregates on the mixture under pressure. On the other hand, the test method of using high-pressure environment to test the performance of the mixture is mainly pressure bleeding test. However, due to the water absorption behavior of lightweight aggregate concrete, it is not suitable to test the pressure bleeding performance of lightweight aggregate concrete.

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