Evaluation of Electrochemical Chloride Extraction

Project summary:

The corrosion of steel rebar in concrete columns is a concern, especially in states where deicing salts are used. A new method has been developed to remove chloride ions permanently from concrete, Electrochemical Chloride Extraction (ECE). This new method of rehabilitation has yet to be demonstrated on any structures in the state of Minnesota. After removal of the chloride, it is beneficial to seal the concrete, to inhibit the ingress of more chloride. The concrete can be sealed using traditional sealants (i.e. Silane sealer) or with fiber reinforced polymer wraps (FRP). However, sealing/wrapping of the concrete may also lead to increased corrosion if water, oxygen and chloride are trapped in the concrete. The project described herein will assess the effectiveness of a combination of ECE and column sealing/wrapping as a method of inhibiting rebar corrosion in concrete bridge piers. The repairs will be demonstrated on a bridge on T.H. I394 over Dunwoody Boulevard in Minneapolis.