Abstract:Three point bending test was used to investigate the effect of steel fiber content by volume on the cracking resistance of reactive powder concrete(RPC). Scanning electron microscopy was employed to study the bonding between the steel fiber and the cementitious matrix. The bonding strength was examined via fiber pull out test. The results show that unreinforced RPC is brittle and low in fracture energy, and the steam curing makes RPC even more susceptible to brittle failure. On the other hand, steam curing can improve the transition zone in the PRC matrix that immediately surrounds the steel fiber. Thus heat treatment improves the bonding between the fiber and the PRC matrix, resulting in better fracture resistance. In comparison with specimens with 1% steel fiber volume faction, when the volume fraction of steel fiber is 2%, heat treatment can no longer give notable improvement of the fracture resistance of RPC.