A Long-Term Performance Evaluation of an Experimental Concrete Overlay

Flexible pavements are often rehabilitated by milling distressed asphalt and placing new asphalt at a thickness that accounts for expected traffic growth and pavement life. However, there are many reported benefits to concrete overlays as a method to rehabilitate and preserve distressed asphalt pavements. In 1988, the Florida Department of Transportation designed and constructed an unbonded concrete overlay on US-1 between Daytona Beach and Titusville. The 1.9-mile concrete overlay was part of a larger 8-mile milling and resurfacing of a deteriorated asphalt pavement. The concrete overlay test sections were divided into three groups based on design thicknesses of 6, 7, and 8 inches. Each of these groups included subsections with three joint spacing levels and two dowel bar configurations consisting of standard 12-inch spacing and wheel path only. The overlay sections are still in service with no major rehabilitation effort. The primary distress is pavement roughness found in sections with wheel path dowels only. The section with the most cracked slabs had joint spacings of 20 ft, which is no longer recommended. This paper documents the experimental program and presents the analysis and findings.