EVALUATION OF HYDRAULIC CEMENT CONCRETE OVERLAYS PLACED ON THREE PAVEMENTS IN VIRGINIA

Three hydraulic cement concrete pavement overlays were placed in the summer of 1995 at three locations in Virginia. Two of the overlays were placed on continuously reinforced concrete pavement to prevent spalling caused by a shy cover over the reinforcement and to enhance the structural integrity. The third overlay was placed to correct a rutted asphalt pavement. The construction was funded with 20 percent Virginia Department of Transportation maintenance funds and 80 percent special ISTEA Section 6005 federal funds specifically allocated to demonstrate overlay technologies. ISTEA funds were also used to evaluate the installation and initial conditions of the overlays and to prepare the report. The variables in the study were concrete mix design, overlay thickness, and base material. Mineral admixtures and steel and plastic fibers were used to improve the mechanical properties and durability of the overlay concrete. Overlay thickness and base material were varied to determine their effect on overlay performance. Overlays that were 51 and 102 mm (2 and 4 in) thick worked well on hydraulic cement concrete pavements. Overlays that were 76 and 102 mm (3 and 4 in) thick worked well on asphalt concrete pavements. These overlays can be used to extend the life of the pavements.