The influence of longitudinal rebar type and stirrup ratio on the bond performance of reinforced concrete with corrosion

Abstract

This study investigated the bond-slip mechanism of eccentrically pulled out rebar under different corrosion level. The variation patterns of the bonding performance between two types of steel rebars (i.e., plain round rebar and ribbed rebar) and concrete with different stirrup ratios were obtained with respect to the amount of steel rebar corrosion. The differences in bonding performance between plain round rebars and ribbed rebars with concrete were compared, and the bond-slip mechanisms of plain round rebars and ribbed rebars with concrete were elucidated. The influence of longitudinal bar type and stirrup ratio on the ultimate bond strength and bond-slip constitutive curve was analyzed. It has been determined that in the case of uncorroded specimens featuring ribbed bars, the ultimate bond strength exhibits an approximately linear increase in relation to the stirrup ratio. Conversely, the stirrup ratio does not have a significant impact on the ultimate bond strength of uncorroded specimens with plain round bars. Transverse reinforcement plays a crucial role in mitigating the effects of cracked concrete by delaying the reduction in bond stress caused by the corrosion rate of longitudinal reinforcement. This phenomenon becomes increasingly prominent when higher stirrup ratios are utilized in the case of plain round reinforcement. Transverse reinforcement serves to suppress the occurrence of the brittle failure stage that follows the peak bond stress in specimens exhibiting a low corrosion rate. The magnitude of this effect becomes more pronounced as higher transverse reinforcement ratios are employed.