Effect of corrosion on bond behaviors of rebar embedded in ultra-high toughness cementitious composite

The bond between corroded rebar and ultra-high toughness cementitious composite (UHTCC) is a key factor in the mechanical properties of corroded reinforced concrete members repaired using UHTCC. This paper presents an experimental study on bond behaviors of UHTCC and corroded reinforcement obtained in a concrete environment through central pull-out tests. The experimental results revealed that all the UHTCC specimens failed in pull-out and that almost all showed an apparent average slip plateau. The post-peak bond behavior was improved with an increase in corrosion ratio. The change in bond strength with corrosion ratio is related to bond length. Bond toughness first rose and then decreased with corrosion ratio, but still remained close to that of non-corroded samples at about 15% of corrosion ratio. An empirical model was proposed to predict the bond strength between corroded rebar and UHTCC, and a good agreement was obtained.