Experimental study on dynamic compressive properties of fiber-reinforced reactive powder concrete at high strain rates

Dynamic compression tests were performed on reactive powder concrete (RPC) using split Hopkinson pressure bar (SHPB) apparatus. A total of 102 RPC samples including plain RPC (PRPC), steel fiber-reinforced RPC (SFRPC) with 2% and 5% volumetric fractions of steel fiber, and hybrid fiber reinforced RPC (SPFRPC) with 0.2% polypropylene (PP) fiber and 2% steel fiber were characterized at high strain rate of 72-317 s(-1). The characteristics of wave transmission, dynamic compressive strength, compressive deformation, energy absorption ability, and dynamic increase factor (DIF) of RPC under high strain rate impact were systematically investigated. Results revealed that the dynamic compressive strength of PRPC was more sensitive than that of SFRPC. With the addition of 0.2% PP fiber, the dynamic compressive strength of SFRPC exhibited a slight decrease. The critical strain increased with increasing strain rate. In all cases of RPC, the critical damage variable decreased with increasing fiber content subjected to same strain rate impact. The energy absorption of RPC increased with increasing content of steel fiber, which was found to be higher than normal strength concrete and high strength concrete. It was observed that application of CEB formula to calculate DIF of RPC was not safe. Thus, an empirical formula for DIF of RPC was proposed based on test data of this study and existing literature results.