Corrosion behavior and mechanisms of steel reinforcement under steady-state DC interference

Purpose With the construction of power supply facilities, stray currents inevitably exist in underground environment, causing interference to steel reinforcement structures and affecting their safety. Accurately assessing and controlling stray current interference is a critical research focus and practical challenge in engineering. The purpose of this study is to investigate the corrosion behavior of steel reinforcement under stray currents interference and to provide insights into its long-term durability and protection. Design/methodology/approach The corrosion behavior of steel reinforcement under steady-state DC interference current densities ranging from 0.01 to 1 mA/cm² has been studied. Mechanisms of the occurrence and development of localized corrosion of steel reinforcement under different current densities were investigated using real-time potential monitoring, macro and micro morphology observation, corrosion product analysis, electrochemical impedance spectroscopy and potentiodynamic polarization measurements at the interference current densities of 0.01 and 0.5 mA/cm² over varying interference times. Findings Results indicate that at 0.01 mA/cm², pitting occurs within 10 h but does not propagate. When the current exceeds 0.02 mA/cm², pitting forms within 10 min and continues to expand, resulting in shallow and wide localized pits. Originality/value The mechanism models of localized corrosion occurrence and development at DC interference of 0.01 mA/cm² and greater than 0.01 mA/cm², respectively, are proposed.