Cold Temperature Creep Compliance and Strength of Missouri Hot Mix Asphalt (HMA) Mixtures Using Indirect Tensile Test

016509162017Final ReportPDFTech Reportcmr 17-014MoDOT project # TR201713Air voidsCalibrationCold weatherCreepHot mix asphaltMechanistic-empirical pavement designTemperatureTensile strengthThermal degradationAASHTOWare (Software)DesignHighwaysMaterialsPavementsIndirect Tensile TestsUnited StatesMissouriMissouri. Dept. of TransportationLusher, Steven M.Missouri University of Science and Technology. Department of Civil, Architectural, and Environmental EngineeringMissouri. Dept. of Transportation. Division of Construction and MaterialsUS Transportation CollectionMissouri Department of Transportation (MoDOT) has for the second time in about 10 years, performed the local calibration of the mechanistic-empirical pavement design guide software, now designated as AASHTOWare Pavement ME Design. Cold-temperature creep compliance and tensile strength of hot mix asphalt (HMA) are the two inputs to the thermal cracking module within the software and are required for local calibration. The test protocol used for this work is American Association of State Highway and Transportation Officials (AASHTO) test method T 322, \u201cStandard Method of Test for Determining the Creep Compliance and Strength of Hot Mix Asphalt (HMA) Using the Indirect Tensile Test Device.\u201d MoDOT-supplied materials were a) 18 different sets of the top lifts (layers) separated from six inch diameter pavement cores, and b) 54 boxes of 150 mm diameter gyratory-compacted specimens (GCSs). The 54 boxes of GCSs were produced from 27 different plant-produced mixes compacted to two levels of air voids per mix. Creep testing was performed at 0, -10, and -20\ub0C (32, 14, and -4\ub0F, respectively) and tensile strength testing was performed at -10\ub0C. Poisson\u2019s ratio was estimated from the creep testing results. With a few exceptions, expected trends of increasing creep compliance with increasing temperature, and decreasing tensile strength with increasing air voids were confirmed during top-lift core and GCS-derived specimen testing. With a couple of exceptions, GCS-derived specimen testing resulted in the expected trend of increasing creep compliance with increasing air voids, at all temperatures. Although they are not required for local calibration of the thermal cracking module, estimated Poisson\u2019s ratio values were reported but did not always follow expected trends (e.g. maximum value of 0.5), especially during the top-lift core testing.75