Construction of a Composite Pavement (Asphalt over Concrete) in Virginia

Abstract

The U.S. Strategic Highway Research Program 2 (SHRP2) identified composite pavement as a “renewal solution” and the Virginia Department of Transportation (VDOT) received implementation funding to demonstrate its feasibility. In 2017, this funding was applied to support major rehabilitation of two westbound lanes of US 60 in Henrico County, Virginia, a project that essentially replaced 1.1 mi of deteriorated concrete pavement with a new composite system consisting of continuously reinforced concrete pavement (CRCP) overlaid with stone matrix asphalt (SMA). This paper documents the design and construction of this new composite pavement. It also includes results from through-the-thickness temperature monitoring and a summary of performance for the first 4 years after opening to traffic. Close oversight by researchers provided a review of challenges and associated lessons learned from the design and construction process. Current VDOT specifications and standards were sufficient for successful construction. The asphalt overlay appeared to reduce the temperature gradient within the CRCP and to moderate daily temperature swings. This insulating effect of asphalt is expected to lower curling and associated stresses in the concrete pavement, which may permit reduced concrete thickness requirements in designs and also enable longer service life. The cracks in CRCP were tight and were not expected to reflect through the SMA. Moreover, the SMA mixture was tested to be crack and rut resistant. Therefore, a crack- and rut-free long service life for this composite pavement is expected. A recent visual survey by researchers found no observable distresses after 4 years under traffic.