The Corrosion Resistance of Reinforced Concrete with Manufactured Sand under Stray Current and Chloride Salt Corrosion

In order to investigate the feasibility of employing manufactured sand as a substitute for natural river sand in the environment of stray current and chloride salts, this study executed a two-stage experimental program. The first stage determined the most effective replacement ratio of manufactured sand by evaluating the effects of different replacement rates on steel reinforcement’s corrosion tendency, postcorrosion performance, and concrete’s microstructural characteristics. The second stage examined the corrosion resistance of manufactured sand concrete under varying conditions (0, 10, 20, and 40 V stray current and 1%, 2%, and 3% chloride concentrations) based on the identified most effective replacement rate. The results indicated that the corrosion resistance of concrete with manufactured sand was generally superior to that of river sand concrete. The most effective corrosion resistance was achieved at a 50% replacement ratio, with steel reinforcement showing a 5% reduction in mass loss rate relative to natural sand concrete after 30 days of corrosion exposure. The combined effect of stray currents and chloride salts was found to exacerbate corrosion compared to environments with chloride salts alone, thereby accelerating the corrosion process of steel reinforcement. Electrochemical measurements revealed that, without stray current, the polarization resistance was approximately 30 times higher, and the corrosion current density was about 49 times lower than under stray current conditions. These findings provide theoretical support for the potential promotion and application of ecofriendly manufactured sand concrete in engineering.