Preparation and properties of hydroxy-terminated polybutadiene polyurethane-modified asphalt

Polyurethane (PU) is currently one of the most widely used polymers, which has the advantages of high strength, high-temperature resistance, and excellent low-temperature flexibility, etc. To address the issues of high-temperature deformation and low-temperature cracking in traditional polymer-modified asphalt. This study prepared four types of hydroxyl-terminated polybutadiene polyurethane (HTPB-PU) modified asphalts through in-situ polymerization, providing a new type of polyurethane-modified asphalt binder. The microstructure and molecular structure of the polyurethane-modified asphalt (PUMA) binder were analyzed using fluorescence microscopy and infrared spectroscopy. Additionally, the rheological properties and adhesion characteristics of the PUMA were investigated. The results indicate that when the HTPB polyurethane content reaches 7 %, the modified asphalt transitions to a two-phase continuous structure, with the polymer phase beginning to influence the rheological properties of the asphalt. As the HTPB-PU content increases, the high-temperature deformation resistance and low-temperature cracking resistance of the modified asphalt improve. Notably, when the PU content exceeds 5 %, resulting in superior low-temperature performance compared to SBS-modified asphalt with 4.5 % SBS content. Moreover, with the increase in HTPB-PU content, the fatigue resistance and pull-off strength between the PUMA and aggregates also improve. This study has successfully prepared PUMA with excellent comprehensive performance, providing a reference for further research and application of PUMA. © 2024 Elsevier Ltd