Performance Characterization of Asphalt Binders and Mixtures Modified with Polyethylene Wax Processed from Postconsumer Recycled Plastics

This study explored using polyethylene (PE) wax processed from postconsumer recycled (PCR) plastics for asphalt modification via the wet process. To that end, a battery of laboratory performance tests was conducted to characterize the properties of asphalt binders and mixtures with and without PE wax modification. Test results showed that PE wax had good compatibility with the two selected base binders in terms of storage stability and morphology results indicating minimum polymer separation tendency. The PE wax stiffened the base binder without affecting its elastic properties. A similar stiffening impact was also observed in the Hamburg Wheel Tracking Test (HWTT) and Indirect Tensile Asphalt Cracking Test (IDEAL-CT) results of the modified mixtures, but to a less significant extent. The Cyclic Fatigue test showed that using PE wax and/or styrene-butadiene-styrene (SBS) modification improved mixture fatigue resistance, and the improvement became more pronounced as the level of polymer modification increased. Finally, FlexPAVE simulations demonstrated the potential thickness reduction benefits of using PE wax and/or SBS-modified mixtures from the pavement structural design perspective.