The latest research progress of polyurethane modified asphalt binder: synthesis, characterization, and applications

Polyurethane (PU) is widely used in the automotive, furniture, and aviation industries. Recently, an increasing number of researchers used PU as a modifier for asphalt pavement modification due to its excellent wear resistance, high-low temperature performance and elasticity. Herein, the latest research progress of PU modified asphalt (PUMA) was reviewed through the following aspects: The preparation process of PU and PUMA; Analyzes the mechanism of polyurethane modified asphalt from a microscopic point of view; The use of molecular dynamics simulation to study the performance of polyurethane modified asphalt. The use of PU as a modifier, such as PU emulsified asphalt, PU foam asphalt, PU recycled asphalt, PU solid-solid phase change asphalt, bio-based PU-modified asphalt, self-repairing PU-modified asphalt; The use of PU and other modifiers composite modify asphalt. For example, PU/nano-materials, PU/SBS, PU/epoxy resin, and PU/warm mix additive modified asphalt; The use of PUMA in tunnels, bridge deck pavements, functional pavements, and special scenarios for crack and pothole maintenance. Furthermore, the challenges and future trends in PU-modified asphalt were reviewed drawing on current research findings.