CIVIL ENGINEERING 365 ALL ABOUT CIVIL ENGINEERING



AbstractThis paper presents an experimental investigation into the effects of aging on the rutting performance of both hot-mix asphalt (HMA) and warm-mix asphalt (WMA) mixtures and an analytical study of how these effects should be reflected in pavement mechanistic-empirical (ME) design and analysis for WMA mixtures. Double-barrel foamed technology and Evotherm additive were selected to produce the WMA mixtures and an HMA mixture with the same volumetric properties as the two WMA mixtures was used as the control mixture. The WMA and HMA mixtures were conditioned at different aging levels and subjected to dynamic modulus tests and triaxial repeated load permanent deformation tests. Also, binder was extracted and recovered from each mixture to evaluate the effects of aging on the binder scale. The results indicate that the two WMA mixtures show less stiffness and more permanent deformation than the HMA control mixture under the same loading conditions. The Double barrel WMA mixture showed greater susceptibility to aging than both the Evotherm WMA mixture and the HMA mixture. The results also show that the ratio of permanent strain to resilient strain, which is the rutting model parameter in pavement ME, is not affected by the level of aging or by mixture type (i.e., HMA versus WMA). However, if these results are implemented in pavement ME, the higher dynamic modulus value obtained from the HMA mixture compared to the WMA mixtures would lead to less resilient strain and therefore less permanent strain. This trend is in agreement with triaxial repeated load permanent deformation test results and the common understanding that HMA mixtures provide greater resistance to permanent deformation than WMA mixtures.



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