Corrosion-Inhibiting Systems for Durable Concrete Bridges. I: Five-Year Field Performance Evaluation

The performance of nine commercially available corrosion-inhibiting systems for use in reinforced concrete structures exposed to corrosive environments was assessed in the field on bridge barrier walls and in accelerated electrochemical cells in the laboratory. The corrosion-inhibiting systems included concrete admixtures, reinforcing steel coatings, and/or concrete surface coatings/sealers. The results of this study are presented in two companion papers, in which the field evaluation and laboratory investigation are reported. The field evaluation consisted of annual corrosion surveys of half-cell potential and corrosion rate, as well as remote monitoring with embedded instrumentation for the measurement of the environmental conditions. After five years of investigation, the system containing an inorganic-based admixture performed better than others in reducing the risk of reinforcement corrosion in the barrier wall. It was also found that the system using epoxy-coated reinforcement showed good early performance during the first year, but after, the risk of corrosion increased relatively faster than in other systems, possibly due to localized pitting corrosion developing in small defects or pores of the epoxy coating.