The evaluation of corrosion inhibitors for the repair and rehabilitation of reinforced concrete bridge components

In 1991, seven corrosion inhibitors, surface applied liquids and concrete admixtures, were identified as promising for the repair of reinforced concrete structures subject to chloride induced corrosion. Small scale (1 ft.²) reinforced concrete specimens were cast to evaluate the inhibitors effectiveness. A treatment matrix was established to evaluate the inhibitors performance on three ranges of corrosion activity and evaluate the effect of application time and drying. Corrosion rate measurements taken with a linear polarization device were used to monitor the inhibitors effectiveness. The effect of the admixtures on the concrete properties, and the effect of the surface applied inhibitors on the overlay bond strength were evaluated. Rapid freeze-thaw tests were conducted to estimate the durability of the inhibitor modified concrete. Three combinations of inhibitors were identified for large scale testing after ten months of accelerated chloride exposure. The larger specimens, removed from an actual bridge deck, were treated to test the effective inhibitors field application techniques. Service life estimates were made for the two combinations of inhibitors which were most effective to aid the engineer in assessing the inhibitors cost effectiveness.