Performance Enhancement of TMT Rebar in Accelerated Corrosion

Thermo-Mechanically-Treated (TMT) bars have recently been used as advancement over the conventional mild steel bars in reinforced concrete structures in order to enhance the durability in corrosive environment. Corrosion of steel reinforcement leads to cracking of reinforced concrete sections and thus may further reduce the load carrying capacity and serviceability of the structural members. Corrosion of rebars may cause reduction in yield strength of steel, affect the bond strength due to delamination of rust formed on the rebar surface. In this paper, the results of an experimental investigation on effects of corrosion on the mechanical strength of TMT steel rebars are presented. Corrosion is induced on the bars by impressed current method. The rebars are subjected to varying levels of corrosion and their stress strain characteristics are studied. The stress strain characteristics indicate a decrease in the area under stress strain curve with increasing level of corrosion. Further, it is observed that the yield strength of steel bars is not affected at a lower percentage of corrosion, but for higher percentage of corrosion there is a considerable reduction in yield strength, percentage of elongation. It was also observed that at a higher percentage of corrosion the failure pattern of bars had changed from ductile mode to brittle mode.