State-of-the-art review on the bond properties of corroded reinforcing steel bar

This review summarizes the latest research progress in regard to the bond behavior of corroded reinforcing steel bar. The literature survey indicates that the previous studies mainly focus on the deterioration of bond strength. The primary factors influencing bond strength, including main bar corrosion, concrete cover, concrete type, stirrups, stirrup corrosion, and corrosion rate, have been well recognized. However, the existing models for bond strength are mostly developed based on specific test results and are not generalized. The corrosion-induced surface crack width is an ideal parameter for the evaluation of bond strength, but models in this respect are still scarce. As for the bond-slip behavior, literature studies reveal that the bond-slip mechanism is hardly affected by corrosion. Currently, discrepancies exist regarding the corrosion influence on the key parameters that shape the bond-slip curves. Preliminary comparisons of the existing bond-slip models show that reliable and generalized models remain to be developed based on larger database. Studies on the bond behavior of corroded steel bar under cyclic loading are quite few. The limited test results indicate that the repeated loading without changing sign shows no apparent influence on bond strength, whereas the cyclic reversed loading exacerbates the corrosion-induced bond deterioration. Knowledge gaps and research areas where further investigations are required are outlined.