Experimental study on interfacial bond-slip behavior of weathering steel and seawater sea-sand concrete in corrosive marine environments

To improve the durability of marine renewable energy infrastructures, this paper proposed a weathering steel reinforced seawater sea-sand concrete (WSRSSC) structure and investigated its interfacial bond-slip behavior. Forty specimens were designed and underwent simulated marine corrosion tests and push-out tests to explore the effect of various factors, including the corrosion time, shaped steel type, steel section form, seawater sea-sand concrete (SSC) strength, and stirrup spacing. The findings indicated that the ultimate bond stress and residual bond stress increase with higher SSC strength but decrease with greater stirrup spacing. The steel section form significantly affected the ultimate bond stress. With the increase in corrosion time, the ultimate bond stress of WSRSSC specimens first increased and then slowly decreased in the later stages. Weathering steel specimens demonstrated superior corrosion resistance and long-term performance compared to carbon steel specimens. Considering the bond formation mechanism and corrosion damage, the calculation model for the ultimate bond stress and residual bond stress of WSRSSC specimens was proposed. Furthermore, the four-stage bond-slip constitutive model between weathering steel and seawater sea-sand concrete was established, aligning with the bond characteristics of different corrosion degrees and contributing to the numerical simulation of WSRSSC structures in corrosive marine environments.