Effectiveness of Thin Hot Mix Asphalt Overlay on Pavement Ride and Condition Performance

摘要

The objectives of this study were: (1) To determine the cost effectiveness of thin hot mix asphalt (HMA) overlays as a maintenance technique; (2) To determine under what conditions a thin overlay would be suitable; (3) To determine the timing of constructing a thin overlay to maximize its benefits; and (4) To develop a prototype aggregate source information system to correlate aggregate source quality to pavement performance. Performance data for thin overlays constructed by ODOT since 1990 were collected to study the cost-effectiveness of thin overlay. The average thin overlay project cost is about 40% of the average minor rehabilitation project cost for the Priority System, and approximately 60% for the General System pavements. In contrast, the average service life of a thin overlay is generally more than 70% of that of a minor rehabilitation. Therefore, most of the thin overlays are deemed cost effective. Thin overlay projects that are not cost effective tend to be those performed on very poor pavements, and with insufficient thickness. Thin overlays are most likely to be cost effective if the existing pavement's PCR score is between 70 and 90 for Priority System, and between 65 and 80 for General System pavements. A prototype aggregate source GIS system was developed. Higher aggregate soundness loss is shown to correlate with higher pavement deterioration rate. A thin HMA overlay is generally a cost-effective maintenance treatment. Employed properly, thin overlay provides a relatively low cost alternative in preserving and extending the service life of the existing pavement.