Evaluation of Electrochemical Chloride Extractions, Fiber Reinforced Polymer Wraps, and Concrete Sealers for Corrosion Mitigation in Reinforced Concrete Bridge Structures

US Transportation Collection2019PDFTech ReportMurphy, Michael S.Chauvin, Mark R.Wiss, Janney, Elstner Associates, Inc.Minnesota. Department of Transportation. Office of Research & InnovationMinnesota. Department of Transportation. Office of Research & InnovationUnited StatesMinnesotaBridgesBridge superstructuresReinforcing steelBridge piersCorrosionChloridesFiber reinforced concreteMN/RC 2019-45(c) 1031290Final ReportReinforced concrete bridge substructures in Minnesota and other northern climates possess an elevated risk for chloride induced corrosion damage, which can reduce capacity and shorten service life. Research was performed in 1997 to investigate new strategies for corrosion mitigation, including electrochemical chloride extraction (ECE) and installation of fiber reinforced polymer (FRP) wrap, which were applied on several corrosion-damaged piers on a 30-year-old bridge in Minneapolis. This report presents the results of follow-up research performed to assess the condition of the treated piers after 20 additional years of service, in order to understand the long-term effectiveness of the strategies implemented. The combination of ECE treatment and FRP wrap installation was found to be very effective, with no concrete distress or probable corrosion activity identified in the treated elements. Poor or mixed performance was observed with all other strategies, including both ECE treatment followed by application of a penetrating sealer and FRP wrap installation that was not accompanied with ECE. In addition, significant chloride contamination occurred in all of the subject piers within the 20 years since the initial study, indicating that neither FRP wrap nor concrete sealers prevented the ingress of new chlorides in the manner in which these systems were installed in the initial study. The findings indicated that performing ECE treatment, or installing FRP wraps, did not alone eliminate the risk of future corrosion activity. The most effective corrosion mitigation strategy to extend the service life of reinforced concrete bridge substructures was to minimize water and chloride exposure.132