NUMERICAL-ANALYSIS OF HIGH-STRAIN RATE SPLITTING-TENSILE TESTS

Experimental splitting-tension tests were conducted on 2-in. diameter concrete specimens in a Split Hopkinson Pressure Bar at strain rates of 4.4, 10.6, and 14.7/sec. The specimens were instrumented with electrical resistance strain gages and break circuits to detect crack initiation and growth. Experimental results indicate that there is a shift of crack initiation time relative to the peak stress. Also, experimental strength vs strain rate data reveal that the dynamic tensile strength of concrete is significantly higher than the static tensile strength. A comprehensive numerical analysis was conducted on the splitting-tensile experiments to investigate the effects of varying the uniaxial tensile strength of the concrete on the crack initiation time, stress state, crack growth characteristics, and failure mode in the concrete specimens. The results of the numerical analyses are used to enhance the understanding of concrete tensile strength strain rate sensitivity.