Rejuvenation performance and mechanism of aged SBS modified asphalt rejuvenated by bio-oil based rejuvenators

To further understand the performance and mechanism of bio-oil based rejuvenators during hot recycling with high-content reclaimed styrene-butadiene-styrene (SBS) modified asphalt pavement (RAP-SBS), three kinds of bio-oil based rejuvenators (R1: waste edible oil (WEO), R2: WEO and SBS compound, R3: WEO and reactive agent compound) with different dosages (4 %, 8 %, and 12 %) were used to prepare rejuvenated SBS modified asphalt in this study. Dynamic shear rheometer (DSR) and bending beam rheometer (BBR) were used to study the rheological performances at high, medium, and low temperatures. Fluorescence microscopy (FM) and Fourier transform infrared (FT-IR) spectroscopy were utilized to reveal the rejuvenation mechanisms. The results show that R1 mitigates the agglomeration of aged SBS, and its rejuvenated asphalts have inferior permanent deformation resistance and superior elastic recovery ability but insufficient stress relaxation at extremely low temperatures. R2 can supplement the SBS phase while the ability to repair the network structure is limited, and the permanent deformation resistance of its rejuvenated asphalts is the best. R3 can effectively restore the network structure through chemical reactions. Its rejuvenated asphalts exhibit the best resistance to fatigue cracking. Also, they can significantly improve the speed of viscoelastic flow to release shrinkage stress at low temperatures. Based on the rheological performances of rejuvenated asphalts, utilizing the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) analysis, the recommended dosages are R2 at 12 %, and R3 at 8 %. •Three rejuvenators based on waste edible oil were utilized to regenerate aged SBS modified asphalt.•The effects on the performance of rejuvenated SBS modified asphalts were investigated at both the macroscopic and microscopic levels.•TOPSIS analysis was applied to select appropriate rejuvenator dosage.