Evaluation of a novel supplemental rejuvenator using vacuum gas oil for aged SBS modified asphalt

The rejuvenation of aged asphalt in the reclaimed asphalt pavement (RAP) is a focus point of achieving efficient recycling of RAP. The objective of this study is to develop a novel rejuvenator using vacuum gas oil (VGO) and evaluate its effectiveness for rejuvenating aged SBS modified asphalt. The effects of this new rejuvenator on low temperature performance and fatigue properties of aged SBS modified asphalt were assessed through bending beam rheometer and linear amplitude sweep tests. Frequency and temperature sweep tests were conducted to compare rheological properties of rejuvenated asphalt with original SBS modified asphalt. The rejuvenating mechanism of the rejuvenator on aged SBS modified asphalt was analyzed based on microscopic characterization techniques and molecular dynamics simulations. The results revealed that the rejuvenator restored low temperature performance and fatigue resistance of aged asphalt while maintaining a high level of high temperature deformation resistance. This demonstrated that VGO effectively replenished light component in asphalt and promoted SBS swelling and dispersion within the asphalt. The rheological properties of rejuvenated asphalt were different from original SBS modified asphalt, and it had more elastic characteristics and lower temperature sensitivity. The novel supplemental rejuvenator restored the performance grade of aged asphalt to its original or even better level, providing a new solution for the efficient recycling of asphalt material. • Vacuum gas oil replenishes light component and promotes SBS dispersion. • The pre-swelling process optimizes the supplemental rejuvenator preparation. • Rejuvenator restores PG grade of aged asphalt to its original or even better level. • The rejuvenator primarily interacts with the aged asphalt through physical blending.