Failure and Repair of Deck Closure Pour on Interstate 81

Abstract

On April 6, 2009, a 3-ft × 3-ft section of a closure pour in a reinforced concrete deck on Interstate 81 punched through. The deck had been cast in 1992 during a deck replacement project in which each lane and shoulder of the deck was replaced while traffic used an adjacent lane. The center closure pour connected the two new deck placements. An examination of the failed section revealed that a total of 18 #5 rebars were sheared to create the hole in the deck. The epoxy-coated rebars had sustained section loss because of corrosion caused by water and chlorides leaking through the construction joint and a transverse crack. Repair consisted of removing an 8-ft wide section of the deck that spanned between the steel beams along each side of the closure pour over the entire length of the bridge, forming the opening, placing corrosion-resistant reinforcement (ASTM A1035) that spanned between the beams, and placing expansive bridge deck concrete prepared with Type K cement. Four slabs removed from the closure pour area were delivered to the Structures and Materials Research Facility of Virginia Polytechnic Institute and State University for evaluation. Evaluation methods included chloride contents, concrete resistivities, corrosion potentials, and currents and the electrical indication of the resistance of concrete to chloride penetration. Results are presented from the evaluation of the closure pour failure and the deck repair.