Implementation of warm-mix asphalt mixtures in Nebraska pavements.

PDFTech ReportMPM-0226-1121-0005-001Warm mix paving mixturesAsphalt pavementsPerformance testsPerformance measurementPavement performanceNebraskaNebraska Transportation CenterKim, Yong-RakZhang, JunBan, HokiUniversity of Nebraska--Lincoln. Dept. of Civil EngineeringNebraska. Dept. of RoadsNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceNTL-HIGHWAY/ROAD TRANSPORTATION-MaterialsNTL-HIGHWAY/ROAD TRANSPORTATION-Construction and MaintenanceUS Transportation CollectionThe primary objective of this research is to evaluate the feasibility of several WMA mixtures as potential asphalt pavingmixtures for Nebraska pavements. To that end, three well-known WMA additives (i.e., Sasobit, Evotherm, and Adverasynthetic zeolite) were evaluated. For a more realistic evaluation of the WMA approaches, trial pavement sections of theWMA mixtures and their HMA counterparts were implemented in Antelope County, Nebraska. More than one ton offield-mixed loose mixtures was collected at the time of paving and was transported to the NDOR and UNL laboratories toconduct comprehensive laboratory evaluations and pavement performance predictions of the individual mixturesinvolved. Various key laboratory tests were conducted to identify mixture properties and performance characteristics.These laboratory test results were then incorporated into other available data and the MEPDG software to predict thelong-term field performance of the WMA and HMA trial sections. Pavement performance predictions from the MEPDGwere also compared to two-year actual field performance data that have annually been monitored by the NDOR pavementmanagement team.The WMA additives evaluated in this study did not significantly affect the viscoelastic stiffness characteristics of theasphalt mixtures. WMA mixtures generally presented better rut resistance than their HMA counterparts, and the WMAwith Sasobit increased the rut resistance significantly, which agrees with other similar studies. However, two laboratorytests\ue2\u20ac\u201dthe AASHTO T283 test and semi-circular bend fracture test with moisture conditioning\ue2\u20ac\u201dto assess moisturedamage susceptibility demonstrated identical results indicating greater moisture damage potential of WMA mixtures.MEPDG results simulating 20-year field performance presented insignificant pavement distresses with no majorperformance difference between WMA and HMA, and this has been confirmed by actual field performance data.Although only two-year field performance is available to date, both the WMA and HMA have performed well. Nocracking or other failure modes have been observed in the trial sections. The rut depth and the roughness of WMA andHMA sections were similar