Salt Damaged Bridge Decks: Cathodic Helps

Cathodic protection of bridge decks against spalling caused by deicing salts has been demonstrated effective in decks already damaged. Construction of new decks may use other means to avoid corrosion of steel rebars by the salts: waterproof membranes; polymer overlays for example. However where delamination is severe or where measurements of salts in the pavement indicate imminent spalling, cathodic protection is more economic than replacing the deck. Potholes are scoured and filled with epoxy first. Then the system is put in place. Silicon iron anodes conduct current through a coke breeze asphalt layer. This current is at a larger voltage than that given off by the corroding rebar and in the opposite direction. This prevents current from leaving the steel and prevents rust. The method has been used for subsurface pipelines for years, but this application is new. Other new methods are considered.