Repurposing waste plastics into cleaner asphalt pavement materials: A critical literature review

Abstract

Abstract Current practice of recycled waste plastics includes 7 major types: polyethylene terephthalate (PETE), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), and others such as acrylonitrile butadiene styrene (ABS), ethylene vinyl acetate (EVA), polycarbonate (PC), and polyurethane (PU). This paper provides a comprehensive and in-depth literature review on the feasibility and the state-of-art repurposing waste plastics into cleaner asphalt pavement materials. Optimum dosage of waste plastics should be identified based on appropriate engineering performance parameters such as viscosity of asphalt, and rutting, fatigue cracking, thermal cracking, and moisture resistance of asphalt mixtures. If the appropriate amount of plastic is not determined, adverse impacts on the performance of the pavement could occur. Plastic wastes are incorporated into asphalt mixes by the dry (aggregate substitute) or wet (binder modifier, extender, or substitute) methods. In general, the incorporation of plastic wastes into asphalt mixes showed improvements in performance parameters such as stiffness, and rutting and fatigue resistance. However, HDPE, PVC, LDPE, PP, and PS yielded conflicting performance measures. Overall, the capability of recycling waste plastics into asphalt mixes would minimize landfilling, reduce dependence on nonrenewable resources, and diversify asphalt pavement building options. Additional research is needed to fully understand the effects of various plastics on the performance of the pavement, and potential environmental and economic impacts this process could implicate. Another area where further study is needed are methods to improve the compatibilization between plastic and asphalt.