How Good Are Thin Asphalt Overlays?

Preserving the road surface and maintaining it at a proper functional level is essential to safe transportation. Several alternatives exist to serve this need and to deliver effective pavement surface preservation. Among these alternatives, high performance thin asphalt overlays have been utilized and promoted by several states in the United States. Under the research presented here, performance of thin asphalt overlays was evaluated through placement of three pilot projects. Advanced technologies such as thermal imaging and ground-penetrating radar were utilized to determine the uniformity of such mixes during placement in regard to temperature and density. Field evaluations, in general, indicated improved performance of these roads with respect to skid resistance and ride quality. Field measurements have indicated minimal rutting, fatigue cracking, and raveling at all three sites after years in service. Reflective cracking has been the dominant distress at all three projects. Overall, it can be assessed that both construction and performance of the three pilot projects has been successful.