Incorporating Impact of Aging on Cracking Performance of Mixtures During Design

US Transportation Collection2019PDFTech ReportSias, Jo EDave, Eshan V.Zhang, RunhuaRahbar-Rastegar, ReyhanehUniversity of New Hampshire. Department of Civil and Environmental EngineeringNew Hampshire. Bureau of Materials and ResearchUnited States. Department of Transportation. Federal Highway AdministrationUniversity of New Hampshire. Department of Civil and Environmental EngineeringUnited StatesAging (Materials)Asphalt mixturesBituminous bindersCrackingMaterials selectionMix designAsphaltpavementpavement crackingpavement designpavement performance.FHWA-NH-RD-26962O26962O, A004(534)Final ReportAging can significantly affect the properties of asphalt binders and mixtures, causing increase in stiffness, reduction in relaxation capability, and increase in brittleness. Eleven mixtures were evaluated in this project using different laboratory conditioning protocols to evaluate how the properties of asphalt binders and mixtures, including rheological properties, fatigue, and fracture behavior will change over time. Comparisons between different aging levels, binders and mixture properties are conducted by using complex modulus (E*), Simplified Viscoelastic Continuum Damage (S-VECD) approach, Semi Circular Bending (SCB) and Disk Shaped Compact Tension (DCT) fracture tests on mix, and 4mm Dynamic Shear Rheometer (DSR) test on binder. By employing the various performance indices of asphalt mixtures and binders measured from the tests, the aging and cracking susceptibility of the mixtures and binders are quantitatively evaluated and investigated. The results show that the two virgin binders and mixtures generally show the good cracking performance after each aging condition. The binders and mixtures with the softer grade and the largest difference between performance grade (PG) high and low temperatures typically have good cracking performance originally, however, they show higher aging susceptibility compared with other materials. Finally, based on the findings from the testing and analysis, suggestions and guidance are developed for NHDOT to quantitatively evaluate the aging and cracking susceptibility of asphalt binders and mixtures during material selection and mixture design incorporating the impact of aging.96