Concrete Pavement Overlays on US-58

Asphalt overlays are typically used to extend the life of continuously reinforced concrete pavement (CRCP) because they can be placed in one or more layers while traffic uses the adjacent lane and they can be opened to traffic in a short time. Hydraulic cement concrete overlays have also been used to extend the life of CRCP but have often not been considered an alternative to asphalt because of the higher cost and longer curing time. In 2012, the Virginia Department of Transportation rehabilitated a 4.8-mile section of the westbound lanes of a CRCP on U.S. 58 in Southampton County using a 4-inch-thick bonded concrete overlay and a 7-inchthick unbonded concrete overlay with a 1-inch asphalt separation layer. The four-lane, divided primary highway is an 8-inch-thick CRCP placed over a 6-inch cement treated aggregate layer. Saw cutting was used to form joints at 6 foot by 6 foot panels for an unbonded overlay, and tie bars were used along the centerline of the pavement and along both shoulders. A concrete overlay was placed on the shoulders of the unbonded overlay, and asphalt was placed on the shoulders of the bonded overlay. Two layers of asphalt with a total thickness of 5 inches were placed on a 9.75-mile section of the eastbound lane of U.S. 58, which provided cost information that was used to compare the alternatives. The project showed that hydraulic cement concrete overlays are a cost-effective and practical alternative for extending the service life of CRCP.