ABSTRACT

Overlays are usually placed on bridge decks to reduce the infiltration of water and chloride ions and to improve the skid resistance, ride quality, drainage, and appearance of the surface. The protection provided by the overlay can extend the life of the deck. Three types are typically used: asphalt overlays on membranes, polymer concrete overlays, and hydraulic cement concrete (HCC) overlays. Asphalt overlays on membranes and polymer overlays have been successfully used on decks that are in good condition but require a skid-resistant surface and protection against chloride intrusion (AASHTO, 1995b; NCHRP, 1995). HCC overlays have been used successfully on similar decks, as well as on decks that require a significant amount of concrete removal and rehabilitation. Overlays are placed on pavements to increase the stiffness and to improve the skid resistance, ride quality, drainage, and appearance of the surface. Both asphalt and concrete overlays are used on both asphalt and concrete pavements. HCC pavement overlays that are thicker than 4 in. are typically unbonded, and HCC overlays that are ≤4 in. thick are typically bonded. The overlays can extend the life of pavements. This chapter deals only with bonded HCC overlays placed on concrete bridge decks and concrete pavements; however, the designs, specifications, materials, and construction techniques should be applicable to concrete decks in buildings, parking garages, and similar concrete structures.