DURABLE BRIDGE DECKS

The report deals with bridge deck durability in Ontario and considers available techniques for the construction and restoration of bridge decks in the light of existing technology. The mechanism of corrosion of reinforcing steel in concrete is outlined and the most significant factors influencing corrosion are discussed. The effect of the material properties of the steel and the concrete are presented together with a review of the environmental factors which control the onset and rate of corrosion. Several strategies for the prevention of corrosion in bridge decks are identified and documented in turn. The relative merits of the following strategies are considered: alternative deicers, corrosion inhibitors, bar coatings, surface treatments and impermeable overlays. Techniques for evaluating the condition of existing decks are summarized and rehabilitation procedures for existing deteriorated decks are reviewed. It is concluded that bonded concrete overlays are the most promising method of achieving the Ministry's goal of maintenance-free bridge decks. It is therefore recommended that bonded overlays be applied to new decks in a two-course construction technique and to existing decks as the basis of a permanent repair procedure. /Author/