Study on the deterioration patterns of reinforced concrete under full immersion environment in subtropical ocean

Abstract

Aiming at the corrosion problem of steel bars in concrete in subtropical marine environment, the full immersion corrosion experiments of reinforced concrete specimens with different strength grades and rust inhibitor contents were carried out by simulating the subtropical marine environment.The macroscopic indexes such as chloride ion content were tested by electrochemical non-destructive testing, and the experimental results were verified by microscopic detection methods.The corrosion degradation patterns of reinforced concrete was analyzed.The results show that the improvement of concrete strength grade and the increase of rust inhibitor content can significantly improve the corrosion resistance of reinforced concrete.Among them, the corrosion resistance of C30 concrete is the worst.At 120 d, the corrosion current density is 0.118 μA/cm2, the polarization resistance is 220 kΩ cm2, the concrete resistance is 87.3 kΩ cm2, and the transfer resistance of the steel-concrete interface area is 77.3 kΩ cm2, reaching the passivation state.When the concrete strength grade is increased to C50, the corrosion current density is reduced by 58.47%, the polarization resistance is increased by 3.82 times, and the concrete resistance is increased by 44.56%;when the amount of rust inhibitors is 6 kg/m3, the corrosion current density is reduced by 47.45%, the polarization resistance is increased by 2.81 times, and the transfer resistance at the reinforcement-concrete interface is increased by 72.43%.

Keywords

• subtropical marine environment
• reinforced-concrete structure
• concrete strength grade
• rust inhibitor
• electrochemistry