Experimental Analysis of Bond between Corroded Steel Bar and Concrete Confined with Textile-Reinforced Concrete

The issue of steel bar corrosion has seriously affected the working performance of concrete structures. Reinforcement is an effective measure to restore the mechanical properties and prolong the service life of concrete structures. Determining the bond properties between textile-reinforced concrete (TRC)-confined concrete and a corroded steel bar is one of the main issues in evaluating the effect of TRC reinforcement. Based on the results of electrochemical corrosion and pullout tests, the bond properties between concrete and a steel bar under unconfined and TRC-confined conditions were comparatively analyzed in terms of the corrosion-induced cracking, failure mode, bond-slip curve, bond strength, and bond failure mechanism. The empirical calculation formula of the ultimate bond strength between unconfined concrete and a corroded steel bar was obtained, and the confinement effects of TRC and fiber-reinforced polymer (FRP) were compared by collecting data from the relevant literature. The research results indicated that TRC confinement can effectively improve the bond properties between concrete and a corroded steel bar and limit the development of corrosion-induced cracks. Furthermore, TRC confinement controlled any further crack expansion during the pulling out of the steel bar. After TRC confinement, the brittle failure characteristic of the bond behavior between concrete and a corroded steel bar was improved, and the failure mode was changed from splitting to splitting-pullout. The confinement effect of TRC using a lower fiber-reinforcement ratio is similar to that of FRP.