Short-Term Performance Characterization and Fatigue Damage Prediction of Asphalt Mixtures Containing Polymer-Modified Binders and Recycled Plastics

Abstract

This study evaluated the short-term performance properties and predicted cracking performance of asphalt mixtures containing polymer-modified asphalt (PMA) binders and recycled polyethylene (RPE). To that end, binder rheological testing, mixture performance testing, and FlexPAVE simulations were conducted. Furthermore, three PMA mixtures were selected for field evaluation on the National Center for Asphalt Technology Test Track and rapid performance testing during production. The PMA binders modified with styrene-butadiene-styrene (SBS), reactive elastomeric terpolymer (RET), and RET-compatibilized RPE had significantly improved elasticity and rutting resistance compared with the unmodified binder. The PMA binders also exhibited good storage stability with minimal separation tendency. Both polymer modification of the asphalt binder and adding RPE via the dry process improved the rutting resistance of the mixture. Although the unmodified and PMA mixtures exhibited notably different load-versus-displacement curves from the Indirect Tensile Asphalt Cracking Test (IDEAL-CT), they had similar cracking tolerance index ( CTindex) results. The Gf-versus- l75 /m75 interaction diagram allowed a more robust understanding of the IDEAL-CT results by considering mixture toughness and brittleness, and their interactions with CTindex. In all cases, polymer modification increased the stiffness and fatigue damage resistance of asphalt mixtures, while adding RPE via the dry process embrittled the mixtures, making them more susceptible to fatigue damage. The PMA mixtures had significantly better predicted cracking performance in FlexPAVE simulations than the unmodified mixture. This improvement was mainly caused by polymer modification of the asphalt binder. Finally, adding dry RPE pellets improved the rutting resistance but reduced the intermediate-temperature cracking resistance of the plant-produced PMA mixture containing an SBS-modified binder.