Inducing pitting in low carbon steel via chloride contamination: Electrochemical noise analysis in concrete gel pore solutions

This study explores an alternative approach to examining the corrosion of reinforced concrete, a persistent and challenging issue. The research utilizes an agar-based gel as a synthetic pore solution to simulate the environment of reinforcing steel, with the goal of confining pitting corrosion induced by chlorides to specific areas of the steel. By employing this innovative approach, metastable and stable pits were successfully induced according to the $\frac{{Cl}^{-}}{{OH}^{-}}$ ratio at pre-selected locations on the steel surface. The presence of metastable pits was determined in the range of 31.6 > $\frac{{Cl}^{-}}{{OH}^{-}}$ > 3.2, as indicated by electrochemical noise analysis. The findings support the efficacy of this experimental procedure for enabling precise manipulation and contamination of localized regions with chloride ions.