Review of recycling waste plastics in asphalt paving materials

An ever-growing demand for depleted natural resources is one of the significant challenges facing the global asphalt pavement industry in building and maintaining global asphalt pavements. Because plastics are ubiquitous in the global economy, they are the latest in a series of high-profile materials to attract attention. Their low material recovery rates and the environmental impact of current disposal methods pose a threat to plastic recycling. Recycling plastic wastes in asphalt pavement is a possible approach to reducing environmental pressure and the demand for depleted natural resources. Many studies have proposed recycling plastic waste in asphalt pavement using dry- and wet-processed technologies. This review aims to comprehensively evaluate the feasibility of various recycled plastics in asphalt pavement concerning the properties of compatibility, storage stability, microstructure, thermo-rheology, and mechanical performance and to identify challenges and recommendations for the future. This review discusses recent developments and the feasibility of using plastic wastes as modifiers or additives to asphalt binders or asphalt mixtures in dry and wet processes, focusing on different materials from waste streams, how to produce such modified materials, and the characteristics of plastic waste modified asphalt, thus contributing to the sustainable management of resources and production of useful paving materials.