Strain-rate effects on the tensile behavior of strain-hardening cementitious composites

摘要

This paper investigated the strain-rate effects on the tensile properties of strain-hardening cementitious composite (SHCC) and explored the underlying micromechanical sources responsible for the rate dependence. Experimental studies were carried out to reveal rate dependence in component phases, i.e. fiber, matrix, and fiber/matrix interface. A dynamic micromechanical model relating material microstructure to SHCC tensile strain-hardening under high loading rates was developed. It was found fiber stiffness, fiber strength, matrix toughness and fiber/matrix interface chemical bond strength were loading rate sensitive and they increase with loading rates in a polyvinyl alcohol fiber-reinforced SHCC (PVA-SHCC) system. These changes in component properties result in the reduction of tensile strain capacity of PVA-SHCC as the strain-rate increases from 10~(-5) to 10~(-1) s~(-1).