Effects of Waste Lubricant Oil on Rheological Properties of Asphalt Binders: Implications for Sustainable Asphalt Mixture Production

Reusing waste lubricant oil as an environmentally -friendly alternative for disposal and transforming it into a valueadded product is a promising solution. This study aimed to evaluate the rheological properties of asphalt binder (PG 64-XX) modified with waste hydraulic oil. Two levels of oil content, 3% and 5% by weight of the base binder, were added. Physical and rheological tests, including penetration, softening point, rotational viscosity, and performance grade (PG) tests, were conducted before and after subjecting the samples to the Rolling Thin Film Oven (RTFO), multiple stress creep and recovery (MSCR), linear amplitude sweep (LAS), and master curve procedures. Results showed that the addition of oil decreased the stiffness of the base binder, making it more susceptible to premature cracking and instability. However, the mixture and compaction temperatures decreased with the oil addition. Overall, considering the investigated oil contents, the asphalt binders modified with waste hydraulic oil did not exhibit satisfactory performance. It is hypothesized that incorporating residual hydraulic oil in recovered asphalt binders may yield more favorable results.