Effects of Strain Rate and Moisture on the Tensile Strength of HeterogeneousMaterials

摘要

Strain rate effects on tensile strength of concrete and mortar were investigatedusing three different size specimens, two different sized split Hopkinson pressure bars (SHPB) and a standard material test machine. All combinations of data show the same trend of abrupt increases in tensile strength at a strain rate of about 1.0/sec. An analytical expression end an empirical relation for concrete tensile strength are presented as functions of strain rate and crack velocity. Crack velocity of concrete and mortar as a function of strain rate was determined using ultra high-speed photography, crack gages, and time of failure for splitting tensile tests in a SHPB. Crack velocity data shows an asymptotic