Resilient modulus and the fatigue properties of Kansas hot mix asphalt mixes

103829973509172Final reportPDFResearch PaperK-TRAN:KSU-02-6RE-0281-01NTIS-PB2007101276C1319Hot mix paving mixturesDynamic modulus of elasticityModulus of resilienceFlexible pavementsBase course (Pavements)StiffnessFatigue (Mechanics)Asphalt testsKansasKansas. Dept. of TransportationRomanoschi, Stefan A.Dumitru, Nicoleta I.Dumitru, OctavianKansas State University. Civil Engineering Dept.Kansas. Dept. of Transportation. Bureau of Materials & ResearchK-TRAN (Research program)University of KansasNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceUS Transportation CollectionThis research study aimed to determine the dynamic modulus, bending stiffness and fatigue properties of four representative Superpave Hot Mix Asphalt (HMA) mixtures used in the construction of base layers of Kansas flexible pavements and to compare the measured values with those predicted by the National Cooperative Highway Research Program (NCHRP) Design Guide. To achieve these objectives, asphalt concrete beams were tested in third point-bending at constant strain, at four temperatures and four levels of strain. Dynamic resilient modulus tests were performed on asphalt cylindrical specimens at five temperatures and five loading frequencies. Multi-linear regression analysis was performed to develop a linear relationship between the bending stiffness and the fatigue life for the asphalt mixes tested. It was found that the dynamic modulus is not a good indicator of the fatigue performance of HMA mixes. At all temperatures and strain levels, the mix containing SBS polymer modified binder had a much longer fatigue life while having similar dynamic moduli with those of mixes with unmodified binders. The measured dynamic moduli on all four mixes were, in most cases, more than two times the dynamic moduli predicted by the NCHRP Design Guide. At the same temperatures and at the same loading frequency of 10 Hz, the measured dynamic moduli were more than two times larger than the corresponding bending stiffness. The fatigue model incorporated in the NCHRP Design Guide over-predicted the fatigue lives of the mixes with virgin binder and severely under-predicted the fatigue life of the mix and with SBS polymer modified binder. /Abstract from report summary page