Impact of Stone Powder Content on Corrosion Resistance in Reinforced Concrete under Stray Current and Chloride Interactions

Abstract

Manufactured sand, known for its artificial production, eco-friendliness, cost-effectiveness, and sustainability, serves as an excellent alternative to natural sand. Stone powder content plays a crucial role in determining the performance of manufactured sand, significantly enhancing concrete compaction and its ability to withstand environmental degradation. This study aims to explore the feasibility of using environmentally and economically advantageous manufactured sand in the construction of subway tunnel segments in coastal areas. It investigates the impact of stone powder content on the corrosion resistance of concrete made with manufactured sand under the combined influence of chloride salts and stray currents. The analysis covers corrosion tendencies, the post-rusting performance of reinforcement bars, the resistance of concrete to chloride transport, and microstructure properties, which are assessed through electron microscope scanning and mercury compression testing. The findings indicate that the corrosion resistance of manufactured sand concrete generally surpasses that of river sand concrete. Furthermore, stone powder content within the 3–8% range leads to a denser concrete microstructure, reduced porosity, lower free-chloride ion levels, increased polarization resistance of post-corrosion reinforcements, lower corrosion current density, and reduced mass loss of reinforcing bars. This research provides valuable theoretical support for promoting the use of environmentally friendly manufactured sand concrete in subway construction projects.