Study on the Deterioration of Reinforced Concrete Under Stray Currents and Chloride-Ion Coupling Effects

This study examined the combined effects of chloride ions and stray DC on reinforced concrete (RC) using electromigration and impressed-current methods under varying current densities (0.5, 3.0, 5.0 mA/cm2) and chloride concentrations (50, 1350, 5500 mg/kg). Chloride was identified as the dominant deterioration factor. At 3.0 mA/cm2, cracking times in moderate and severe chloride environments decreased by 48.75% and 52.62%, respectively, compared to mild conditions. At 0.5 mA/cm2 in severe conditions, the corrosion rate reached 1.317% after 20, 2.75 times that in moderate conditions. Electromigration specimens showed delayed cracking but deeper chloride penetration, while impressed-current specimens exhibited pronounced strip-shaped pitting corrosion. A quadratic polynomial model predicting cracking time based on current density and chloride concentration achieved high accuracy (R2 = 0.95, mean relative error = 7.%). Actual corrosion mass loss was lower than theoretical Faraday values, with current efficiency increasing from 0.3–0.8% to 16.5–18.1% as current density and chloride content rose. These findings highlight the synergistic effect of stray current and chloride attack, emphasizing chloride concentration’s greater impact on service life. The model provides a scientific basis for RC durability design in urban rail transit and coastal engineering.