Use of infrared thermography to detect thermal segregation in asphalt overlay and reflective cracking potential.

PDFTech ReportSWUTC/15/600451-00111-1DTRT12-G-UTC06ThermographsInfrared imageryBituminous overlaysReflection crackingFinite element methodTemperaturePavement jointsDifferential thermal analysisUnited StatesSouthwest Region University Transportation Center (U.S.)Elseifi, Mostafa A.Dhakal, NirmalGulf Coast Center for Evacuation and Transportation ResiliencyUniversity Transportation Centers Program (U.S.)US Transportation CollectionThe objectives of this study were to assess whether temperature differentials measured using InfraredThermography (IRT) occur in an overlay built on top of discontinuities such as joints and cracks and tostudy the horizontal and vertical thermal profiles in the asphalt overlay using a validated Finite Element(FE) modeling approach. To achieve this objective, an infrared camera was used to monitor thetemperature profiles in the asphalt mat in a number of field projects from the time it was placed to aftercompletion of the compaction process. The temperature profiles were monitored on top and away ofsevere discontinuities and joints in the existing pavement. Results showed that thermal measurements ontop of the joints were consistently lower than away from it, which may indicate that temperature loss mayoccur at the joints. Further, a validated FE model predicted a slightly higher rate of thermal loss at thebottom of the overlay above the joint than away from it due to convection losses at the joint. While thisdifference may not be large enough to be identified as thermal segregation, it can influence the bulkproperties of the overlay at the joints and promote early cracking. Thermal differences were also observedin the vertical direction as lower temperatures were predicted at the top and the bottom of the overlayduring construction due to convection losses with the ambient atmosphere and conduction between the hotoverlay and the existing pavement