Effects of Non-uniform Corrosion on the Bond Behavior of Steel Bar in Concrete

This study aims to investigate the bond behavior of non-uniformly corroded steel in concrete. Eccentric pull-out tests were carried out on 36 concrete specimens. The experimental variables included non-uniformly of corrosion, stirrups confinement and corrosion levels of longitudinal bars and stirrups. The influences of corrosion characteristics, corrosion level and stirrup confinement on the bond degradation were analyzed. The cracking patterns of corrosion-induced cracks, bond failure modes, and bond stress-slip relations were discussed. The results showed that the corrosion level and the stirrup confinement significantly influenced the cracking patterns of corrosion-induced cracks, and the corrosion of stirrups could lead to serious cover cracking. In comparison to the concrete specimens embedded with uniformly corroded steel, the bond performance of specimens containing non-uniformly corroded steel degraded more significantly, and this phenomenon became even more pronounced as the corrosion level increased. In comparison to the case that merely longitudinal steel bar was corroded, the corrosion of both longitudinal steel bar and stirrups exacerbated bond deterioration.