Stripping Detection in Asphalt Pavements with Seismic Methods

Abstract

Stripping of hot-mix asphalt pavements has been a significant problem for many transportation agencies. The detection of stripping has been carried out by using either visual observation or laboratory strength tests of cores retrieved from the field. Ground-penetrating radar also has been used for this purpose. Seismic methods are presented here as a nondestructive tool to detect the extent of stripping. Seismic tests are beneficial because they are rapid to perform and nondestructive and because the material is tested in its natural state. The portable seismic property analyzer (PSPA) is an example of a device that uses two methods of analysis to detect stripping: ultrasonic surface wave (USW) and impact echo (IE). PSPA results and field cores retrieved (ground-truth data) from two sites were compared. PSPA, with the standard receiver spacing of 6 in., correlated well with cores when they were located in the first 10 in. of the asphalt layer (shallow). For deeper stripping, longer spacing between the receivers should be used. From the two methods of analysis, the USW method was found to be more effective than the IE in visualizing the extent and depth of low-quality layers in terms of asphalt stiffness.