Study on the Self-Healing Performance of Polyurethane/Graphene Oxide-Modified Asphalt Based on Dynamic Disulfide Bonds

In this study, an investigation on using polyurethane/graphene oxide (PU/GO) containing disulfide bonds as a modifier to improve the self-healing ability of asphalt was conducted. PU/GO with different GO contents were synthesized and modified asphalt with different PU/GO dosages (2%, 4%, 6%, 8%) were also prepared. The effect of GO contents on the mechanical and self-healing properties of PU/GO was explored and the impacts of PU/GO contents on the basic properties and self-healing properties of asphalt were also investigated. The results indicated that GO could significantly improve the mechanical properties of PU, as the tensile strength of PU/GO with 1.6% GO increased by more than 100% compared with pure PU. Moreover, GO also had a positive impact on the early-stage self-healing properties of PU/GO. PU/GO could be well dispersed in asphalt and clearly improve the low-temperature performance of base asphalt. When the PU/GO content is 8%, the ductility of modified asphalt was almost 6 times that of base asphalt. The results of both ductility and BBR self-healing tests revealed that the addition of PU/GO improved the self-healing properties of asphalt under room temperature and infrared light conditions. Especially under infrared light conditions, the ductility self-healing coefficient of 8% PU/GO-modified asphalt could reach 100% after healing for 15 min.