COMPARISON OF DYNAMIC CAPABILITIES OF GRANITE AND CONCRETE UNDER UNIAXIAL IMPACT COMPRESSIVE LOADING

Experiments with strain rate varying from 101 s-1 to103 s-1 on granite and concrete under uniaxial compressive loading are conducted with the modified split Hopkinson pressure bar(SHPB).It can ensure the symmetrical stress in the specimens before fracture and avoid the fluctuation of test data due to input shaky stress pulse by adding the copper wafer as the pulse shaper.The experimental results show that the compressive strength and the fragment numbers of rock-like materials increase with the strain rate.The fragment size decreases with the strain rate.The initial elastic modulus,the failure strain and the ratio of the energy absorption of granite and concrete can be seen no relations with strain rate under condition that strain rate ranges from 101 s-1 to 103 s-1.The stress-strain curves,the energy absorbency-time curves and the ratio of the energy absorption-time curves of granite and concrete are compared.It is illustrated that the microstructure characteristic,impedance,compression deformation capability of rock-like materials are crucial factors influencing the characteristics of dynamic fracture.The research method and conclusions can be used to analyze the dynamic behavior of the other brittle materials.