Bond and corrosion behavior of steel bar embedded in cracked concrete exposed to marine environment

Different marine corrosion zones exposure has various impact on steel bar corrosion and bond properties. In this work, 27 beam specimens were prepared to evaluate the corrosion states and bond properties of steel bar embedded in cracked ordinary performance concrete (OPC), highperformance concrete (HPC) and ultra-high-performance concrete (UHPC) exposed to artificial simulated marine corrosion zones for 360 days. The corrosion zones include atmospheric zone, water level fluctuation zone and immersion zone. Electrochemical test showed that corrosion rate of steel bar embedded in cracked concrete reduced over time. Steel bars embedded in the same type of cracked concrete corrode most severely in the water level fluctuation zone and least severely in the atmospheric zone. Cracked beam specimens exposed to water level fluctuation zone experience alternating wet/dry cycles, which enhances the capillary adsorption effect and increases the diffusion and penetration of chloride ions. The steel bar resistance of specimens exposed to the same corrosion zone increases as the concrete strength increases. Flexural bond test showed that bond strength of steel bar embedded in cracked concrete increases significantly as the concrete strength increases. The bond strength, bond stiffness, bond ductility and bond toughness showed highest values when specimens exposed to the atmospheric zone, followed by immersion zone, and then the water level fluctuation zone.