Performance Monitoring Pavements with Thermal Segregation in Texas (0-6080-1)

This project conducted work to investigate the performance of asphalt surface mixtures that exhibited thermal segregation during construction. From 2004 to 2009, a total of 14 construction projects were identified for monitoring. Five of these projects did not exhibit thermal segregation, while the remaining projects did exhibit thermal segregation. In all cases, a Pave IR thermal profiling system collected data during construction. Follow-up surveys using visual examination, ground-penetrating radar, and in some cases focused coring, were used to evaluate whether the locations of thermal segregation showed significant distress. The projects constructed free of thermal segregation have not shown any distress due to segregation. Results from projects constructed with thermal segregation present were mixed. In some cases, traffic action seems to have homogenized the pavement surface. On other projects, evidence of thermal segregation still exists shown by different surface appearance and localized changes in radar data. One project showed evidence of cracking due to segregation. Core results from field projects suggested the segregated locations will be more prone to cracking. This research project's results certainly do not show that thermally segregated locations will definitely fail within three to seven years of service; however, the results do show that instances of thermal segregation may continue to be anomalous locations in the layer, even after subsequent overlays, and exhibit properties that could lead to failures in the pavement structure.