Innovative Self‐Healing Asphalt via Dynamic Covalent Bonding: Design, Characterization, and Application of Crosslinked Desulfurized Rubber

ABSTRACT A novel self‐healing asphalt binder was developed by incorporating dynamic covalent crosslinked desulfurized rubber (DCR) into asphalt. The DCR was synthesized via hot‐press crosslinking of desulfurized rubber with liquid polysulfide rubber, introducing dynamic disulfide bonds into the network. Fourier‐transform infrared (FTIR) spectroscopy and 13 C nuclear magnetic resonance (NMR) confirmed the successful formation of the dynamic crosslinked structure. The DCR exhibited excellent fracture self‐healing and reprocessing capabilities, with the optimal formulation (DCR‐45) achieving a healing efficiency of 90.8% after 1 h at 60°C. DCR was then melt‐blended with base asphalt to prepare dynamic covalent crosslinked desulfurized rubber modified asphalt (DAP). Fracture and fatigue self‐healing evaluations demonstrated that DAP‐15 (15 wt% DCR‐45) possessed the best healing performance, with a fracture healing ratio of 88.48% after 6 h at 80°C, significantly outperforming the control sample without dynamic bonds. A healing model analysis revealed that the incorporation of DCR enhanced the diffusion‐based healing rate of asphalt. The self‐healing mechanism is attributed to the combined effect of asphalt flow and the dynamic exchange of disulfide bonds within the DCR network under thermal stimulation. This work provides a promising strategy for designing intrinsic self‐healing asphalt materials with extended service life.