Study of Rutting and Roughness in Asphalt Overlay and Local Calibration of Roughness Prediction Model in 2002 Design Guide (05-1800) - MP-08
Haifang Wen, Washington State University
Hani H. Titi, University of Wisconsin, Milwaukee
Darrell Berry, Bloom Consultants, LLC

Currently, the state highway agencies are spending numerous efforts and funds in highway rehabilitation projects. Asphalt overlay of existing asphalt and concrete pavements is one of common pavement rehabilitation methods. The performance of asphalt overlay is affected by many factors and varies significantly. This study investigated the factors influencing the performance of overlay, in terms of rutting and roughness. Previous asphalt overlay projects were retrieved and current performance of these overlays was reviewed and analyzed. It was found that rutting in asphalt overlay of concrete pavements was insignificant in most of cases and increased with the increase of traffic volume experienced. The roughness in asphalt overlay of concrete pavement was positively correlated with initial roughness right after the placement of asphalt overlay, demonstrating the importance of profile index of overlay. The rutting in asphalt overlay of existing asphalt pavement was highly correlated with pre-overlay rutting. It indicated that asphalt overlay might not be an effective rehabilitation method for existing asphalt pavement with severe rutting. It was also found the roughness in asphalt overlay of asphalt pavement decreased with the increase of overlay thickness. The roughness prediction model for asphalt overlay of existing concrete pavement used in 2002 design guide was calibrated with the locally available data.