Improving Durability of Reinforced Concrete Structures Using Migrating Corrosion Inhibitors

Abstract

Abstract Steel corrosion poses formidable concerns for long term reliability of reinforced concrete structures. In the United States, with its vast infrastructure of concrete and steel bridges, superhighways, and reinforced concrete buildings, billions of dollars have been spent on corrosion protection. Among the commercial technologies available today, migrating corrosion inhibitors (MCIs) show versatility in their use as admixtures, surface treatments, and in rehabilitation programs. The effectiveness of two commercial inhibitors applied to the reinforced concrete surface was evaluated. The corrosion behavior of the steel rebar was monitored using AC electrochemical impedance spectroscopy (EIS). Corrosion potentials and polarization resistance values corroborated the inhibiting effects of the amine carboxylate and amino alcohol chemistry in an aggressive environment. The MCI products have successfully inhibited corrosion of the rebar in a 3.5% NaCl solution for duration of testing. MCI protected samples showed an average corrosion rate of 0.34 μA/cm2 compared to untreated samples that were 1.50 μA/cm2. This will increase the life expectancy by more than 15 years. XPS analysis demonstrated the presence of inhibitor on the steel rebar surface indicating MCI migration through the concrete.