Use of waste engine oil residue for sustainability in road construction

There are several waste materials that are abundantly available in all countries, and their disposal is causing harm to the environment. Handling these resources improperly can be hazardous to living beings. In this research, one such resource, waste engine oil residue (WEOR), is considered for the partial replacement of the asphalt binder. WEOR contains a complex mixture of pollutants, including heavy metals, polyaromatic hydrocarbons (PAHs), and other harmful substances, which require careful handling. This study aims to explore environment-friendly utilization of WEOR in the asphalt binders and evaluate its performance after long-term aging. The study is divided into two parts. The first part consists of an environmental check for the utilization of WEOR, and the second part evaluates the performance change of the asphalt binder modified with WEOR. The environmental tests show no significant concentrations of heavy metals and no emission of hydrogen sulfide (H₂S) gas into the atmosphere while blending WEOR with asphalt binder. The X-ray diffraction analysis indicated that the introduction of thermoplastic copolymer (TPC) with the WEOR led to amorphization (enhanced elasticity) and stabilization in the asphalt binder. This phenomenon of amorphization helped the extended binders resist the aging process, as quantified by fluorescence microscopy and Fourier transform infrared spectroscopy, showed a reduction in PP parameter and chemical aging index by up to 53 % and 13 %, respectively. The performance of the extended binders after aging was better than that of conventional asphalt binders, which was observed with the reduction in complex modulus shifting parameter up to 50.6 units in extended binders. Therefore, WEOR, with a small portion of TPC, was found to be a sustainable material to reduce the consumption of asphalt binders in road construction.