Chemical and rheological properties evaluation of a novel synchronous rejuvenated aged SBS modified asphalt

The aging hardening of neat asphalt binder and the aging degradation of styrene-butadiene-styrene (SBS) polymer could significantly shorten the service life of the SBS modified asphalt (SBSMA) pavement and produce vast waste asphalt pavement materials. In order to recycle and reuse the aged SBSMA in a sustainable way, a green compound rejuvenator, which consists of aromatic oil and triallyl isocyanurate (TAIC), was developed to restore the original properties of the aged SBSMA based on the synchronous rejuvenating mechanism (i.e., colloidal structure regulation and SBS polymer structural reconstruction). The rejuvenating efficiency of the newly developed compound rejuvenator was first verified by fluorescence images, functional group characteristics, and molecular weight distributions of the SBSMA before and after rejuvenation. The rheological properties of the synchronous rejuvenated SBSMA (SRSBSMA), including the high-temperature permanent deformation resistance, low-temperature anti-cracking resistance, and fatigue resistance performance, were subsequently tested and compared with those of the SRSBSMA developed in previous studies. The results showed that aromatic oil had the capability to stabilize the unbalanced colloidal structure of the aged neat asphalt binder, while TAIC underwent a chemical reaction with the active group of the aged SBS to reconstruct the crosslinking network structure of the SBS modifier. Additionally, the rheological test results indicated that the performance of SRSBSMA restored by the new compound rejuvenator was the closest one to that of the virgin SBSMA as compared with the existing rejuvenators. To this end, the newly developed compound rejuvenator is proven to be promising in restoring the properties of SBSMA, which thus can be used to efficiently rejuvenate the aged SBSMA pavement.