Chemical Treatment of Corroding Steel Reinforcement After Removal of Chloride-Contaminated Concrete

Abstract

The increasing use of deicing salts on bridge decks has accelerated their deterioration due to chloride-induced corrosion of steel reinforcement, which causes cracking and spalling. One method being considered as a possible corrosion abatement measure is the removal of chloride-contaminated concrete followed by chemical treatment of the partially exposed rebar through ponding and/or placement of chemically treated mortar. Several commercial and experimental corrosion inhibitors were evaluated in order to determine the most effective corrosion treatment when applied in conjunction with removal of chloride-contaminated concrete. The performances of the inhibitors were evaluated in an accelerated test program. Based on post-treatment electrochemical measurements, calcium-nitrite-based corrosion inhibitor was most effective when applied as a ponding and when placed in backfilled mortar. Several other inhibitors were also sufficiently effective and were recommended for further evaluation in large-scale and field experimentation. On the other hand, several inhibitors affected the hydration process of portland cement.