Dynamic Splitting and Tensile Properties Experiments of High-Strength Concrete with Different Initial Damage

To further investigate the dynamic splitting and tensile properties of existing damaged high-strength concrete structures under impact loading, the dynamic splitting and tensile properties of two types of high-strength concrete with different initial damage under impact loading are investigated using a separated Hopkinson compression bar device. Meanwhile, the crack evolution of the specimens was monitored based on digital image processing techniques.The results show that: The strain rate sensitivity of C60 concrete at a high strain rate is significantly higher than that of C80 concrete at the same initial damage level. With the increase in strain rate, the strain rate sensitivity of the specimens with a lower damage level is higher, and the strain rate sensitivity of C80 concrete with high damage level decreases. With the increase of initial damage level, the microcracks generated inside the concrete increase, and the energy consumed by the formation of new cracks was significantly greater than that consumed by the expansion of cracks at initial damage. Based on the DIC technique, it was found that the microstrain threshold and crack opening displacement of C80 concrete showed a decreasing trend as the initial damage level increased.