(Received 25 December 2011; accepted 15 May 2012)
Published Online: 2012
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This study evaluated the viscoelastic properties of a performance grade binder modified with different dosages of a selected wax-based warm mix asphalt (WMA) additive (WMA1). The effects of reduced rolling thin film oven (RTFO) aging on the stiffness of the WMA1-modified binder were also evaluated. The viscoelastic properties of the modified binders were then used to estimate the dynamic modulus (E*) values of the WMA mixes through time temperature superposition principles. Furthermore, the effects of a selected liquid anti-stripping agent (ASA), ASA1, on the properties of the WMA1-modified binder were investigated. It was observed that the linear viscoelastic limits of WMA1-modified binders decreased with an increasing dosage of WMA1. Reduced RTFO aging was found to have significant effects on the stiffness of the WMA1-modified binder. The Hirsch model was found to provide better approximations of the E* values than the Witczak model. The Witczak model, based on dynamic shear rheometer data, was found to significantly underestimate the E* values. Although ASA1 did not reduce the beneficial effects of WMA1, it was found to increase the E* values of the WMA mix. The findings of this study are expected to offer transportation professionals a better understanding of the evaluation of WMA binders and mixes.
Research Associate, School of Civil Engineering and Environmental Science, The Univ. of Oklahoma, Norman, OK
David Ross Boyd Professor and Aaron Alexander Professor, School of Civil Engineering and Environmental Science; and Associate Dean for Research and Graduate Programs, College of Engineering, Norman, OK
Stock #: JTE104639