The bond response of corroded reinforcement in concrete under reversed cyclic loading influences the seismic analysis and repair of long-term service concrete structures. After considering variations of coupling corrosion (corrosion ratios of main reinforcement and stirrup) and confinement conditions (cover thickness and stirrup spacing) in actual structures, this study designed and fabricated twenty eccentric pull-out specimens with deformed reinforcement embedded in concrete. The characteristics of reinforcement corrosion, the patterns of cover cracking, the loading failure features, and the bond-slip failure mechanisms were investigated. The results showed that coupling corrosion resulted in transverse and oblique corrosion-induced cracks on the surface of the concrete cover. The compaction effect of slight corrosion on the steel-concrete interface could improve the bond performance and increase the peak bond strength. As the coupling corrosion increased, the wedge effect at the interface weakened, resulting in significant reductions in characteristic parameters of bond strength, deformation, and energy dissipation. Thicker concrete cover or closely spaced stirrups improved the hysteretic bond response at the interface. Finally, an empirical bond-slip damage model for coupling corrosion of main reinforcement and stirrups was developed based on the Weibull distribution damage statistical theory and experimental data. Comparison of the model with experimental curves showed satisfactory accuracy.

Reinforced Concrete; Coupling Corrosion; Reversed Cyclic Loading; Bond Performance; Bond Stress-slip Model