Review of research on waste plastic modified asphalt

Abstract To further explore the application of waste plastics in asphalt pavement, this paper begins with the classification and characteristics of waste plastics. It then provides a state-of-the-art review of the preparation methods and processes of waste plastic modifiers, waste plastic-modified asphalt, and waste plastic-modified asphalt mixtures. The paper also analyzes the factors influencing the compatibility between waste plastics and asphalt and summarizes the performance evaluation indicators for waste plastic-modified asphalt and its mixtures. It explores the research approaches and findings of domestic and international scholars and presents examples of waste plastics applications in pavement engineering. This study concludes that there is a basic consensus that waste plastics can improve the high-temperature performance of asphalt. The use of cracking processes to solve the storage stability of waste plastic polymer-modified asphalt is the key to promoting its application. Additionally, future research is expected to prioritize optimizing automated sorting and chemical pretreatment for efficient plastic waste recycling, advancing composite modifiers through polymer-additive synergies, and validating long-term pavement performance via accelerated aging and extended field trials. Concurrently, efforts will focus on integrating life-cycle sustainability metrics into policy frameworks, advocating incentives like tax breaks, and establishing technical standards to scale eco-friendly plastic-modified asphalt applications. These steps aim to enhance compatibility, durability, and environmental benefits in infrastructure systems.