Experimental study and analytical model of the bond behavior of corroded reinforcing steel bars in concrete

The corrosion of longitudinal rebar and stirrups will cause serious degradation of the bond performance between steel bars and concrete. To investigate the impact of both longitudinal rebar and stirrup corrosion on the bond behavior, 35 reinforced concrete (RC) pull-out specimens were subjected to accelerated corrosion tests with electroosmosis/constant current/dry-wet cycling and pull-out tests. The influence laws of the degree of corrosion of the longitudinal reinforcement, degree of corrosion of the stirrups, cover thickness, stirrup spacing and longitudinal reinforcement diameter on the bond performance were also investigated. The bond behavior between corroded steel bars and concrete was analyzed from the aspects of corrosion form, failure mode and bond strength. Subsequently, based on the experimental data, a modified bond-slip constitutive model that considers the design parameters, stirrup corrosion and longitudinal rebar corrosion was built and verified. The modified bond-slip constitutive model was applied to the cohesive element to establish a finite element model of the corroded pull-out specimens, and additional parameters were analyzed.