Fiber Reinforced Concrete Overlays for Bridge Structures

Rigid overlays measuring 1.5 to 2 inches are placed on bridge decks to improve the ride quality and lower the permeability of the concrete over the reinforcement. Low permeability concretes resist the penetration of water and harmful solutions into concrete. On the other hand, cracks in concrete can facilitate the intrusion of solutions. Chloride solutions induce corrosion of reinforcement, which is the leading distress in bridge decks. Corrosion products cause cracking and spalling of the concrete above the reinforcement and in later stages can cause failure of the reinforcing bars. Rigid overlays are prone to cracking if proper placement and curing procedures are not followed. Cracks in decks can reflect through the overlays. Rigid low-permeability overlays with synthetic or steel fibers can be placed on bridge decks that will control cracking and resist intrusion of solutions into concrete. These fiber reinforced concretes can enable overlay thicknesses less than 1 inch. Lower thickness can reduce dead load, reduce materials cost, and contribute to sustainability.