Analytical and Experimental Compressive Behavior of Reinforced Concrete Columns Subjected to Stray Current and Chloride Ingress

Stray current-induced corrosion poses a significant risk to the durability of reinforced concrete (RC) structures in electrified transit systems. This study addresses a critical knowledge gap by experimentally and analytically investigating the compression behaviors of circular RC columns under the combined effects of stray currents, chloride intrusion, and sustained service loads. The experimental program involved testing columns constructed with normal strength concrete (NSC) and moderate strength concrete (MSC) under accelerated corrosion induced by electrical potentials of 9 V and 18 V in a 3.5% NaCl solution. A key variable was the application of a sustained axial load, equal to 60% of the ultimate capacity, to simulate realistic service conditions. The findings revealed a severe deterioration in structural performance due to the synergistic effect of mechanical loading and corrosion. NSC columns subjected to 18 V potential and sustained axial loading exhibited a decrease in ultimate load-carrying capacity of up to 46% and a ductility reduction of approximately 69% compared to reference specimens. This damage was significantly more severe than in unloaded or lower-voltage (9 V) scenarios. Furthermore, MSC specimens demonstrated a strength loss of approximately 29% under similar aggressive conditions. An analytical confinement model, adjusted to account for corrosion by reducing the reinforcement cross-section and introducing a semi-empirical parameter α to represent localized pitting, showed strong agreement with the experimental stress–strain curves. The validated model provides a practical tool for assessing the residual capacity of corroded elements, addressing a crucial need in the maintenance of electrified transportation infrastructure.