Concrete bridge decks in Calgary are exposed to de-icing salts leading to deterioration due to chloride induced corrosion of steel reinforcement. Service life predictions for older concrete bridge decks are essential in developing cost-effective repair and rehabilitation strategies. The current methodology to determine the condition of the bridge deck consists of two parts: 1) determination of potential for corrosion by the half-cell potential test and 2) determination of the chloride ion content profile on concrete cores obtained from the deck combined with petrographic examination of the concrete. The standardized ASTM C876 test for corrosion potential was developed for black steel reinforcement. Current construction methodologies for bridges utilize epoxy-coated rebar and galvanized steel reinforcement, polymer modified asphalt overlays, high density concrete, and steel-fibre concrete. These changes to bridge deck construction have rendered the standard method used for corrosion potential prediction unsuitable. A bridge deck with a steel-fibre concrete overlay in Calgary was surveyed using the ROAD RADAR(tm) Technology developed by EBA Engineering Consultants Ltd. The findings from the nondestructive ROAD RADAR(tm) survey, the condition of extracted cores, and the chloride ion diffusion profiles formed the basis for the life cycle model developed. For the covering abstract of this conference see ITRD number E220308.
Abstract