Influence of Asphalt Layering and Surface Treatments on Asphalt and Base LayerThickness Computations Using Radar

摘要

The study has been carried out with the specific objective of evaluating theinfluence of thin overlays and surface treatments on the accuracy of pavement thickness calculations using radar. Nine SHRP GPS and SPS sites located on three Texas primary roads were surveyed with radar: two each with a slurry seal, a chip seal, a new overlay, and an old overlay, and one of original construction. Cores were taken at accessible locations to obtain ground truth for asphalt and base thickness. The radar and core data was analyzed to determine the influence of the overlays on the accuracy of the radar computations, and to evaluate analytical techniques which would lead to the highest degree of accuracy. The results show that the thickness of overlays as thin as 1 inch can be accurately evaluated. The results also show that the overall accuracy of asphalt and base thickness calculations can be improved if the appropriate analytical techniques are applied. In certain circumstances, however (one thin low density overlay and one chip seal), the accuracy was reduced. The accuracy of the base thickness