Study on Mechanical Response and Constitutive Model of Rubber Concrete under Impact Load and Water Content Coupling

Impact tests were implemented on concrete with five different types of rubber content utilizing a separated Hopkinson bar with a 50 mm diameter for investigating the mechanical performance of and damage variations in rubber concrete under the coupling effect of water content and impact load. The findings indicate that regular concrete is commonly stronger than rubber concrete, but rubber concrete has better plasticity. At the same time, with an increase in water content, the peak stress of rubber concrete increases gradually, among which RC-6-3 exhibits better mechanical behavior. Water content and rubber content have a significant influence on the fractal dimension of rubber concrete, showing that the fractal dimension is proportional to the amount of glue and inversely proportional to the water content, and RC-12-2 can be used to judge the damage degree of a specimen. As the content of water and rubber grows, so does the rate of energy use. The ratio of transmitted to incident energy decreases gradually as the rubber content increases and is enhanced as the water content is elevated. Among the specimens, tests on RC-9 resulted in the opposite conclusion. In the same water content state, there is a negative association between the content of rubber and the ratio of reflected energy to incident energy. In the natural state, RC-6 rubberized concrete exhibits a significant downward inflection point in the ratio of reflected energy to incident energy. Finally, based on the unified strength theory, a new damage constitutive model of rubber concrete is established and verified.