Regeneration mechanisms of aged SBS modified asphalt from RAP materials: Molecule structure, morphology, phase transition, and interface adhesion characteristics

In this study, the environmentally friendly rejuvenators with waste thermal conductive oil, polymer, and the interfacial reinforcing agent were prepared. And the influence of the different rejuvenators on the rejuvenation mechanisms of aged SBS modified asphalt was characterized by different scales including the molecule structure, morphology, phase transition and interface adhesion characteristic, and macro performance. The results show that the thermal-oxidative aging process increases the molecular weight of asphalt, promotes the SBS phase to agglomerate, and decreases the high and low temperature performance, thermal stability, and adhesion. When the rejuvenator was added, the molecular weight distribution of asphalt binders can be improved, while adding the regenerant-II can supplement the SBS modifier and reform the cross-linking structure. Furthermore, the regenerant-II has a better recovery effect on the morphology structure and resumes the thermal behavior. And then softening point and ductility can be recovered by 89.7% and 94.8% of the original SBS modified asphalt. Under the action of the interfacial reinforcing agent, the regenerant-III could increase the adhesion work to 95.49% of the original SBS modified asphalt.

Automated summary

In this study, environmentally friendly rejuvenators composed of waste thermal conductive oil, polymer, and interfacial reinforcing agent were prepared. The effects of different rejuvenators on the rejuvenation mechanisms of aged SBS modified asphalt were characterized at different scales, including molecule structure, morphology, phase transition, interface adhesion characteristic, and macro performance. The results showed that the rejuvenator could improve the molecular weight distribution of asphalt binders and reform the cross-linking structure of SBS phase. The addition of regenerant-II had a better recovery effect on the morphology structure and thermal behavior, while regenerant-III enhanced the adhesion work of the original SBS modified asphalt.