Status Of Thin Bonded Concrete Overlays PDF Download

This report discusses the performance of the Virginia Department of Transportation's first modern rehabilitation project involving a thin-bonded portland cement concrete overlay of an existing jointed concrete pavement. The performance of the rigid overlay, which was constructed in a fast-track mode to minimize lane closure time, was evaluated by detailed condition surveys conducted annually throughout a 6-year analysis period to identify, document, and monitor the occurrence of distress. The roughness of the overlay was also measured annually with an accelerometer-based inertial road profiler to permit an examination of the effects of surface deterioration on ride quality. After 6 full years of service, which included only minimal maintenance, the pavement overlay remained in good overall condition. Although the ride quality of the overlay remained virtually unchanged throughout the period, a significant increase in the occurrence of low-to-moderate-severity joint spalls, corner breaks, and to a lesser extent transverse cracks was noted during the fifth and sixth years. The extrusion of compression seals and the subsequent infiltration of water into the pavement structure probably contributed to the observed localized failure of the overlay/substrate bond in the vicinity of joints. This condition, in turn, weakened the pavement's structural capacity at panel edges and thereby resulted in the formation of corner breaks and cracks parallel with and near transverse joints. The consideration of thin-bonded concrete overlays constructed in a fast-track mode is recommended as a viable rehabilitation alternative for jointed concrete pavements that are not severely distressed. However, careful attention to joint installation and, in particular, joint maintenance is recommended for similar future rehabilitation projects.