Rheological and Chemical Characteristics of Waste Engine Oil Residue–Based Bitumen

With the rapid depletion and scarcity of bitumen resources, researchers are exploring alternative binders for the construction of asphalt pavements. This has led to exploration of additives or substitutes that not only meet requirements but also enhance the physical and chemical properties of conventional binders. This research partially replaced base bitumen with waste engine oil residue (WEOR). The residue was added to base binder in proportions of 15%, 20%, and 25% by weight, and the modified binder was prepared with blending durations of 30, 40, and 50 min. The thermal storage stability of WEOR-modified binders was evaluated to check the homogeneity of the blended materials. Tests such as fluorescence microscopy and Fourier-transform infrared spectroscopy (FTIR) were conducted to determine the dispersibility of the residue in the base binder and the changes in the chemical composition of the base and modified binders respectively. Frequency sweep tests were conducted to evaluate the rheological properties of the blends. The higher blending duration resulted in a more homogeneous blend of the materials. Increased WEOR content led to a reduction in stiffness, which in turn resulted in poor resistance to rutting in lower-frequency traffic conditions. Furthermore, the effect of aging on the modified binders was analyzed using multiple stress creep recovery tests and linear amplitude sweep tests. It was found that the modified binders performed better than the base binder at lower stress and strain levels.