(LIU Miaoyan, LU Jun, MING Pan. Fracture properties of rubber concrete under three-point bending[J]. Hydro-Science and Engineering, 2021(3): 31-40. (in Chinese)). doi: 10.12170/20200411001
Citation: (LIU Miaoyan, LU Jun, MING Pan. Fracture properties of rubber concrete under three-point bending[J]. Hydro-Science and Engineering, 2021(3): 31-40. (in Chinese)). doi: 10.12170/20200411001

Fracture properties of rubber concrete under three-point bending

  • Through the rubber concrete three-point bending beam fracture test, the load, deflection and crack opening displacement values of the rubber concrete are measured, and the load-deflection curve and the load-crack opening displacement curve are drawn; according to "Hydraulic Concrete Fracture Test Regulations" and ASTM specifications, the fracture toughness and fracture energy are calculated, and the effect of different rubber contents on the fracture performance of concrete and the relationship between the cumulative energy of acoustic emission and fracture energy are studied; and the calculation results of the different fracture toughness calculation formulas given in the two codes are compared and analyzed. The test results show that the maximum load that the concrete can withstand after mixing with rubber is reduced, and the crack initiation toughness, unstable fracture toughness, fracture toughness, fracture energy and cumulative energy of acoustic emission are all reduced; the effective crack length and maximum deflection are the smallest when the rubber content is 10%, and increase when the rubber content is 20% and 30%; the ductility index gradually increases with the increase of the rubber content, and the maximum increase is 41%; and by fitting the fracture energy of concrete harmonic emission cumulative energy curve, the empirical formula in the form of y=a+b\rme^cx can be obtained. The ductility and deformability of the concrete are improved with the incorporation of rubber, the brittleness is improved and an empirical formula can be used to deduce the degree of damage to the concrete when a certain value of emitted energy is reached.
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