Bond-Slip Behavior of Corroded Rebar Embedded in Ultrahigh Toughness Cementitious Composite

Corroded reinforced concrete (RC) members are repaired using ultrahigh toughness cementitious composite (UHTCC), and the bonding between corroded rebar and UHTCC has a significant effect on the mechanical properties of repaired members. In the present paper, the bond behaviors of UHTCC and corroded reinforcement obtained in a concrete environment were investigated via central pullout tests. Parameters including the corrosion ratio and the ratio of the cover thickness to the rebar diameter (c/d) were varied. The experimental results revealed that, compared with concrete specimens, UHTCC specimens exhibited a higher nominalized bond strength and full bond-slip response with a slip plateau near the peak bond stress. The dependence of the bond strength on the corrosion ratio was correlated with c/d. Furthermore, at the considered corrosion levels, the residual bond strength and the bond toughness of the corroded rebar were higher than that of the noncorroded rebar. A bond-slip constitutive model derived from the existing models was proposed, and the predicted curves provided a reasonable description of the bond characteristics.