Polyester Polymer Concrete (PPC) overlays are a common method of bridge deck preservation in Oregon. The Oregon Department of transportation has several years of experience with PPC and has chosen PPC for many large projects including signature bridges like the US 101 Conde McCullough Memorial Bridge in Coos Bay and the I-205 George Abernethy Bridge in Portland. For the Eagle Creek Viaduct, designers choose to continue the commitment to long term quality and rehabilitate the deteriorated bridge deck with Kwik Bond Polymers’ PPC 1121 Polyester Polymer Concrete.
SCOPE OF WORK
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.
The new riding surface of the Eagle Creek Viaduct is smoother than it was the day the deck was poured. The PPC has remained bonded to the steel finger joints and the new surface has shown no signs of wear through high traffic and winter conditions. The Oregon DOT has shown a commitment to using PPC as an effective rehabilitation strategy for bridge decks, and now has tested its bond capabilities beyond previous expectations.