The Solution

The contractor for this project was very experienced with PPC. Prior to placing the overlay, all unsound concrete in the existing deck was removed and replaced with PPC. The overlay was then placed at ¾” thickness over the entire surface of the bridge. The DOT wanted to establish a smooth riding surface, and avoid grinding a rebate into the deck, up to the joints. This meant the PPC would be placed over the steel finger joints. The overlay would have to bond to steel, which is more difficult than bonding to standard concrete. The high molecular weight methacrylate primer included with PPC 1121 gives the product a distinct advantage when bonding to anything, particularly a less porous surface. This primer bleeds into the substrate then reacts with the polyester binder to form an integrated chemical bond to all substrate surfaces, even steel. The joint gap through the center of the finger joint was formed up to proposed grade, and the PPC overlay was placed directly over the steel finger joint to achieve a smooth grade across the entire bridge.