Laboratory evaluation on the aging susceptibility of reclaimed asphalt bitumen containing low-viscosity binder and cooking oil waste

This study investigates the use of cooking oil waste (COW) and low-viscosity binder (LVB) to improve the performance of reclaimed asphalt pavement (RAP) binders and promote the consumption of by-product materials. The aging resistance capacity of experimentally aged asphalt binders with COW as rejuvenators and recently synthesized high-penetration asphalt binders was evaluated using the Rolling Thin Film Oven Test (RTFOT) and the Pressure Aging Vessel (PAV) tests. The Dynamic Shear Rheometer (DSR) Test, Hamburg Wheel Tracking, and Overlay Tester (OT) were used to evaluate the dynamic shear characteristics and performance of the modified RAP mixture. The test results show that using low-viscosity binder (LVB) positively affected the quality of reclaimed asphalt binder after prolonged aging periods. Additionally, the dynamic shear modulus of the AP1 mixture was 5% less than the reference mixture after the PAV condition, indicating a reduced stiffness effect. Considering the performance of reinforced RAP mixture, all RAP mixtures withstood a load of 20,000 cycles settling under 20 mm after 10,000 cycles. In mix COW1, COW5, and LVB, the final settlement was 3.75 mm, 3 mm, and 2.66 mm. Meanwhile, the load reductions of the above mixes were 73.3%, 74.2%, and 76.4% after 1000 OT cycles. In conclusion, utilizing LVB in RAP binder can produce equivalent benefits as applying a rejuvenator additive, even at a high asphalt content (40%) threshold. This research can offer insights into improving the performance of RAP binders in service and promoting the development of green construction.