Recycling high-dosage SBS-modified Reclaimed Asphalt Pavement (RAP) into high-grade asphalt pavement based on a novel warm mix asphalt-synchronous rejuvenation (WMA-SR) technology

Indiscriminate disposal of styrene butadiene styrene (SBS)-modified reclaimed asphalt pavement (RAP) leads to significant environmental issues and waste of valuable materials. To address this issue, this study explores and validates the feasibility of recycling the high-dosage SBS-modified RAP mixtures at high dosages into the surface layer of the high-grade asphalt pavement based on a warm mix asphalt-synchronous rejuvenation (WMA-SR) technology with a synchronous rejuvenation composite (SRC) synthesized. The optimum ratios of aromatic oil and triallyl isocyanurate (TAIC) in the SRC were first identified as 4.20 % and 4.82 %, respectively, using the FTIR peak area ratio restoration. Sasobit and Evotherm 3 G, two WMA additives, were afterwards combined with different types of rejuvenators to fabricate WMA-recycled asphalt mixtures at RAP dosages of 20 %, 40 %, and 60 %. Subsequently, a series of performance property tests were then conducted on the WMA-recycled asphalt mixtures, and a balanced mix design approach (BMD) was employed to identify the Sasobit as the suitable WMA additive and 40 % as the maximum SBS-modified RAP mixture dosage. Finally, the feasibility of the BMD on the RAP mixture design was proven through the long-term fatigue resistance tests. Evaluation results indicate that both the SRC and WMA additives are indispensable for the promotion of high-dosage SBS-modified RAP mixtures into high-grade asphalt pavement recycling.