Effects of Stray Current on Chloride Ingress in Underground Reinforced Concrete Structures

The proliferation of electrified rail systems has intensified stray current effects on chloride-induced corrosion in underground reinforced concrete (RC) structures, yet coupled mechanisms of stray current and chloride ingress—particularly in cracked concrete—remain insufficiently researched. This study establishes numerical models integrating chloride diffusion and electromigration to investigate stray current impacts on chloride transport in intact and cracked RC structures. Results reveal that stray current accelerates chloride ingress, with non-uniform electric fields causing 20–50% faster depassivation time of rebar than uniform fields at equivalent intensities. Cracked concrete exhibits 2–5 times shorter depassivation times of rebar compared to intact concrete, where crack depth–concrete cover thickness ratios exceeding 0.6 reduce service life by 40–60%. A novel deterioration coefficient β is formulated, demonstrating quadratic dependence on stray current voltage and linear correlation with cover thickness. These findings provide a predictive framework for durability assessment and corrosion mitigation in underground infrastructure exposed to synergistic chloride-stray current aggression.