Microscopic, thermochemical, and rheomechanical measurements of rejuvenated/modified binders incorporating waste tractor oil and sawdust pyrolysis agents

This study aims to evaluate the influence of waste-derived rejuvenators and modifiers on asphalt binder performance through microscopic, thermochemical, and rheomechanical measurements. Waste materials derived from recycled tractor engine oil and post-consumer sawdust pyrolysis agents, including bio-oil (BO), separated bio-oil (SBO), engine oil (EO), and biochar (BC), are used to rejuvenate recycled asphalt binder (RAB) and modify virgin asphalt binder (VAB). EO and SBO (5–15%) were used to rejuvenate RAB, while BC (5–25%) was added to modify both VAB and 15% EO-rejuvenated RAB. Comprehensive testing, incorporating SEM/EDX, FTIR, TGA, and CHNS/O analysis alongside penetration, softening point, and advanced rheological tests (RV, DSR, MSCR, and LAS), revealed optimal concentrations of 15% EO and 25% BC. Results demonstrate that EO effectively rejuvenates RAB, while BC significantly enhances the high-temperature stability and fatigue resistance of both VAB and rejuvenated binders. The findings highlight a synergistic effect between waste-derived rejuvenators (SBO and EO) and modifiers (BC), underscoring their potential to improve asphalt performance sustainably. This research provides a viable pathway for integrating waste-derived materials into pavement engineering, offering both environmental benefits and enhanced material durability. Future research is suggested to optimize practical applications and assess long-term field performance.