Cyclic bond property of steel reinforced recycled concrete (SRRC) composite structure

Abstract For the composite structures consisting of the steel profile and recycled concrete, the interfacial bond property between steel and concrete is the most critical factor for the collaborative work. In order to study the interfacial bond property of steel reinforced recycled concrete (SRRC) structures, seven SRRC specimens were fabricated and then tested cyclically. The influences of replacement ratio of recycled aggregate and compressive strength of recycled concrete on the bond behavior of this combination were assessed by looking at failure patterns, hysteretic performance, backbone curves, characteristic loads and corresponding slip, bond strength degradation, and degradation mechanism. Test results showed that the replacement ratio of recycled aggregate dominates the onset of slip between steel and recycled concrete. The obvious pinching phenomenon appears on the hysteresis curves, indicating apparent slip characteristics between the steel profile and recycled concrete. As the chemical cementing force gradually loses effectiveness, the bond strength mainly relies on the friction to maintain the stress balance after the interfacial bond layer gradually crushes. Based on the experimental results, a simplified bond-slip model was proposed and divided into four parts, i.e. intact, hardening, degradation and failure stages, and the degradation mechanism corresponding to each segment was then analyzed in detail.