Preparation and Properties of Self-Healing Polyurethane-Modified Asphalt Composed of Different Soft Segments

AbstractWhen asphalt pavement is in practical use, it is prone to cracking and other diseases due to the long-term effects of load and climate and the restricted self-healing properties of the asphalt material. In order to improve the properties and durability of asphalt pavement, we introduced disulfide bonds into polyurethane (PU) in this study. We prepared polyurethane-modified asphalt (PUA) containing dynamic disulfide covalent bonds using polytetrahydrofuran (PTMG), polyethylene adipate (PEA), and hydroxyl-terminated polybutadiene (HTPB) as soft segments. Subsequently, the rheological properties, healing performance, and microstructure of the PUA were studied. The results indicated that the PU with disulfide bonds was integrated into the asphalt and had good dispersity. A cross-linked network structure formed between them. PUA with HTPB as the soft segment had excellent high-temperature deformation and low-temperature cracking resistance and a prominent advantage in durability. In comparison, PUA synthesized with PEA had better high-temperature performance and fatigue resistance, and PUA synthesized with PTMG had considerable low-temperature properties and stability. The disulfide bonds had a positive impact on the high-temperature performance, aging resistance, and healing properties of PUA through constant dynamic exchange and topological rearrangement effects. This study provides a reference for the preparation of PUA with ideal self-healing ability and has instructive significance for the selection of soft segment materials for synthesizing PUA.