Laboratory evaluation of rejuvenation effect of reactive rejuvenator on aged SBS modified bitumen

A reactive rejuvenator (RR) containing epoxy functional groups and a conventional rejuvenator (CR) were used to regenerate the aged SBS modified bitumen (SBSMB). Effects of two kinds of rejuvenators on physical properties, rheological properties, chemical structure and phase morphology of the aged SBSMB were investigated. Compared with CR, RR performs better in recovering the physical and rheological properties of aged SBSMB, especially for ductility, 9 wt% RR could recover the ductility of aged SBSMB to a level which is close to virgin SBSMB, and the RR shows more effective regeneration effect in the repeated aging and regeneration. FTIR and phase morphology analysis indicates that epoxy functional groups in RR could react with carboxylic groups formed in the degradation of SBS and generate carboxylic ester group, which could bond those oxygenated chain fragments of SBS, enhance the interaction among the SBS chains and partially offset the degradation of SBS chains and the swelling and dilution effects of oily compositions on SBS, resulting in good restoration of the network structure of SBS and the ductility of SBSMB.