Dynamic modulus test method of permeable concrete based on dynamic three-point bending test

Abstract

The invention discloses a testing method for a dynamical modulus of water-permeable concrete based on a dynamic three-point bending test. The testing method comprises the following steps: putting a selected test piece on a fatigue testing machine; symmetrically arranging two supporting supports at the lower part of the testing piece; arranging a force application support at the upper part of the test piece; padding metal gaskets among contact surfaces of the lower supports, the upper force application support and the test piece; adjusting parameters of the fatigue testing machine, and applying dynamic circulating load on the test piece; applying grade by grade and obtaining a deflection change value and a load change value of each grade of load at the last second; obtaining deflection time travel curves and load time travel curves under different loads; solving the amplitude of the two curves under each grade of the load and substituting into a deflection formula, so as to obtain the dynamical elastic modulus. According to the testing method disclosed by the invention, the whole modulus of the water-permeable concrete is inversely calculated through the dynamic small-deformation three-point bending test; partial numerical value deflection caused by the fact that materials are aggregated and air pores are arrayed irregularly at different sites in a resonance method is avoided, and the accuracy of experiment data is greatly improved.

Description

technical field [0001] The invention relates to the field of civil engineering, in particular to a method for testing the dynamic modulus of permeable concrete based on a dynamic three-point bending test. Background technique [0002] The dynamic modulus of elasticity of concrete is generally determined by the resonance method. The basic principle of using the resonance method to test the dynamic modulus is to detect the natural resonant frequency of the object through the method of spontaneous source frequency traversal. Under the condition that the working conditions and the material itself remain unchanged, the resonant frequency is only the density as the only independent variable. function, the specific formula is: [0003] [0004] Among them, f—the fundamental frequency of the specimen, d—the side length of the cross section of the specimen, m—the mass of the specimen, l—the length of the specimen, and E—the dynamic modulus of elasticity. [0005] During the oper...

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Problems solved by technology

[0006] However, for permeable concrete, because the distribution of materials on its surface is not uniform, it is an irregular arrangement of aggregates and pores. , the measured dynamic modulus results have a large deviation. The resonance method cannot accurately measure the dynamic modulus of concrete. It is greatly affected by the local material properties of the probe, and the test results cannot reflect the overall macroscopic modulus of the material.

[0007] A large number of tests have shown that the test results of the dynamic modulus of permeable concrete measured by the resonance method are very discrete. Therefore, a new method and system for testing the dynamic modulus of permeable concrete is urgently needed to complete the test of the dynamic elastic modulus.

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