Research on self-healing behavior of asphalt modified by polyurea elastomer containing dynamic disulfide/diselenide bond

Adding self-healing materials to asphalt can improve the service life of asphalt pavement. In this research, three kinds of polyurea elastomers (PE) with self-healing properties were prepared: the elastomer containing disulfide bonds (PE-S1) obtained by one-step copolymerization and the elastomers containing disulfide/diselenide bonds (PE-S2/PE-Se) obtained by two-step copolymerization. The three elastomers were used as modifiers to prepare corresponding modified asphalt. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy demonstrate the successful preparation of the elastomer containing disulfide/diselenide bond. The results of fluorescence microscope and fracture-healing-tensile test demonstrated that elastomers containing dynamic di-sulfide/diselenide bonds had self-healing capability. Dynamic chemical bonds and synthesis steps had an impact on the thermal stability of the elastomer, but these were not enough to affect the preparation of elastomer modified asphalt. The results of tensile ductility test showed that all three kinds of elastomer modifiers could improve the self-repairing ability of asphalt binder, and the optimum content was 4%. At the same time, there are differences in the self-healing properties of elastomer modified asphalt with different dynamic chemical bonds and synthesis steps. PE-Se elastomer modified asphalt had the better short-term healing capability. PE-S1 elas-tomer modified asphalt had greater advantages in long-term healing capability.