PROPERTIES OF STEEL FIBER REINFORCED CONCRETE SUBJECTED TO IMPACT LOADING.

The effect of strain rate on the flexural behavior of unreinforced matrix and three different fiber reinforced concrete (FRC) mixes are discussed. FRC mixes are more rate-sensitive than their respective unreinforced matrices, showing increases in dynamic strength (strain rate of 0. 3/sec) of up to 111 percent and energy absorption (up to deflection of 0. 1 in. left bracket 2. 5 mm right bracket ) of up to 70 percent (v//f equals 1. 5 percent) over comparable values at the static rates (strain rate of 1 multiplied by multiplied by (times) **sec). Composites made with weaker matrices, higher fiber contents, and larger fiber aspect ratios are more rate-sensitive than those made with stronger matrices, lower fiber contents, and smaller fiber aspect ratios. Several observations made in the study suggest that the rate sensitivity exhibited by such composites is primarily due to a change in the cracking process at the different rates of loading.