Effects of steel fiber and strain rate on the dynamic compressive stress-strain relationship in reactive powder concrete

Three types of steel fiber-reinforced reactive powder concrete (SFRPC) with steel fiber contents of 0%, 2%, and 5% by volume are tested under dynamic compression by using a 40-mm-diameter split Hopkinson pressure bar (SHPB) apparatus. Data from SHPB experiments are employed to analyze the influence of critical parameters on the dynamic compressive stress-strain relationship of SFRPC at high strain rates. Test results show that steel fiber has a significant effect on the stress-strain relationship and energy absorption of RPC. Peak strain and peak stress increase with the increasing steel fiber content at the identical strain rates. A dynamic compressive damage-softening model for SFRPC at high strain rates is put forward on the basis of the Weibull distribution of SFRPC strength. A theoretical formula for Ed was established in order to ascertain Ed for the proposed constitutive model. The ratio of Ed to static elastic modulus Es increases with increasing strain rate and decreasing steel fiber content. The proposed constitutive model captures the dynamic compressive stress-strain relationship of SFRPC, and theoretical results are in agreement with measured data.