Impact characterization and modelling of cement and asphalt mortar based on SHPB experiments

The dynamic behaviour of cement and asphalt mortar (CA mortar, including types CAI with the asphalt/water-to-cement ratios of 0.85/0.78 for the Shinkansen track and CAII with the asphalt/water-to-cement ratios of 0.30/0.50 for the Bögl track) was experimentally investigated under impact loading using a Split Hopkinson Pressure Bar (SHPB). The strain rate effects on the compressive strength, elastic modulus, peak strain and specific energy absorption were obtained. The results showed that the compressive strength and specific energy absorption increased with increasing strain rate, whose strain rate sensitivity for CAI was stronger than that for CAII. The strain rate sensitivity of the elastic modulus and peak strain scattered. Under similarly high strain rates, the compressive strength, elastic modulus, peak strain and specific energy absorption of CAII were larger than those of CAI. A statistical continuous damage constitutive model involving the strain rate for CA mortar was proposed based on the theory of thermodynamics and statistical damage mechanics. The theoretical results showed a consistent comparison with the experimental data.