Effect of Lube-Cut and refined waste oil on physicochemical properties of RAP binders

Waste engine oil (WEO) and Lube-Cut show great potential as rejuvenators for restoring aged asphalt binders in reclaimed asphalt pavement. This study evaluates filtered WEO (FWEO), refined WEO (RWEO), Lube-Cut, and vacuum bottom (VB) through chemical and performance tests, including thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy, frequency sweep, linear amplitude sweep, and bending beam rheometer. Results reveal that Lube-Cut and RWEO have high thermal stability, with less than 1% mass loss during TGA, while FWEO shows 2% loss and VB and unrefined WEO lose 5% and 13%, respectively. FTIR indicates binders with RWEO have the lowest aging indices (0.7–1.2), reducing oxidation-related groups effectively. Morphological improvements were also seen with RWEO. The study highlights Lube-Cut as a cost-effective standalone rejuvenator and confirms that refining or filtering WEO improves rejuvenation performance. Both RWEO and Lube-Cut are sustainable options for enhancing aged asphalt. Furthermore, the study supports SDG 9, SDG 11, and SDG 12 by utilising waste-derived rejuvenators to improve recycled asphalt, and contributes to SDG 13 by reducing energy consumption and emissions linked to new asphalt production.