Bond-slip response of corroded SD bars with recycled coarse aggregate concrete

Abstract

Recycled aggregate concrete (RAC) has been the subject of numerous research to ensure the efficient use of aggregates made from recycling old concrete by examining various parameters in fresh and hardened phases. The present study investigates the bond-slip response of Recycled coarse aggregate concrete (RCAC) with Super Ductile (SD) reinforcing steel exposed to corrosion with varying degrees. SD rebar category is relatively new compared to the hot-rolled and TMT classes of reinforcing steel. SD has a superior bonding performance with concrete owing to the distinctive rib patterns. RILEM-specified cylindrical pull-out specimens were fabricated with RCA concrete with replacement ratios of (0%, 25%, 50%, 75%, and 100%) and centrally embedded SD bars. Pull-out specimens were immersed in NaCl solution before exposure to impressed current corrosion to achieve desired levels of corrosion. The specimens were tested for failure in a displacement-controlled Pull-out testing universal testing machine (UTM). A set of linear variable displacement transducers (LVDT) recorded the slip of the rebar at both the loaded and unloaded ends. The bond-slip response was used to characterize the overall behavior of the bond mechanism. Predictive models have been suggested for the bond strength of RCAC following corrosion. The results indicate that the bond strength of RCAC is almost similar to that of the natural aggregate concrete (NAC) exposed. The results indicated that both the bond slip and bond degradation hold good and agree with previous models. The findings can help anticipate the performance of structural elements made of recycled coarse aggregate concrete (RCAC) exposed to aggressive environments.