Project title: Performance histories of thermally segregated HMA

792930816Technical report; Dec. 2007-Aug. 2011.PDFTech ReportFHWA/TX-12/0-6080-10-6080-10-6080Asphalt concrete pavementsCracking of asphalt concrete pavementsPavement crackingThermal stressesTexasTexas Transportation InstituteSebesta, StephenScullion, TomTexas Transportation InstituteTexas. Dept. of Transportation. Research and Technology Implementation OfficeUnited States. Federal Highway AdministrationNTL-HIGHWAY/ROAD TRANSPORTATION-MaterialsNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceUS Transportation CollectionThis project conducted work to investigate the performance of asphalt surface mixtures that exhibitedthermal segregation during construction. From 2004 to 2009, a total of 14 construction projects wereidentified for monitoring. Five of these projects did not exhibit thermal segregation, while the remainingprojects did exhibit thermal segregation. In all cases, a Pave-IR thermal profiling system collected dataduring construction. Follow-up surveys using visual examination, ground-penetrating radar, and in somecases focused coring, were used to evaluate whether the locations of thermal segregation showed significantdistress. The projects constructed free of thermal segregation have not shown any distress due tosegregation. 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 thermalsegregation still exists shown by different surface appearance and localized changes in radar data. Oneproject showed evidence of cracking due to segregation. Core results from field projects suggested thesegregated locations will be more prone to cracking. This research project\ue2\u20ac\u2122s results certainly do not showthat thermally segregated locations will definitely fail within three to seven years of service; however, theresults 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