Pilot Applications of Electrochemical Chloride Extraction on Concrete Bridge Decks in Virginia

A new method for rehabilitating salt-contaminated concrete bridge elements, electrochemical chloride extraction (ECE), was applied on two deck spans in Virginia as part of a pilot study. This treatment, performed on half of the deck at a time, involved placing a temporary electrolyteanode system (inert catalyzed titanium mesh sandwiched between two layers of synthetic felt) on the surface of the deck and applying charges ranging from 741 to 1,077 A-hr/m² between the anode and the rebars for 57 to 58 days. Approximately 72.2 to 82.1 percent of the chloride ions were removed from the concrete. A minor difficulty was encountered in controlling the pH of the electrolyte during the first several weeks of the treatment. Lithium ions, which were present in the electrolyte for two portions of the deck, migrated readily into the concrete. An attempt to simultaneously inject the corrosion inhibitor (C₆H₅)₄P⁺ in the concrete in the presence of Li⁺ yielded uncertain results. Overall, this pilot project successfully demonstrated that an effective ECE treatment is simple to perform on a full-size concrete deck.