Bonding behavior between reactive powder concrete and normal strength concrete

In order to investigate the bonding behavior between reactive powder concrete (RPC) and normal strength concrete (NSC), splitting tensile test of 81 specimens and double shear test of 27 specimens were conducted, the effects of water-to-binder ratio (W/B) of RPC, steel fibre volume fraction, and interfacial roughness on RPC-to-NSC bonding were investigated. The results showed that the interfacial roughness was the most important factor affecting the bonding shear strength and splitting tensile strength, followed by the RPC W/B, and finally the steel fibre volume fraction. The increase of interfacial roughness in the range of 2.11–6.01 mm and the steel fibre volume fraction in the range of 1%-2% can improve the splitting tensile strength and shear strength. The effect of RPC W/B increase in the range of 0.2–0.24 on the splitting tensile strength was positive, but the shear strength increased first and then decreased with the increase of RPC W/B, the maximum shear strength appeared at 0.22 W/B. Based on the test result, a NSC-RPC shear strength formula considering the interfacial treatment was proposed.