The synergistic effect of waste engine oil and organic montmorillonite on properties of bitumen: Conventional, high-temperature rheological, and self-healing

Abstract

In order to conserve non-renewable natural resources, recycling waste engine oil (WEO) in bitumen can help lower CO2 emissions and advance the environmental economy. This paper makes an effort to investigate the viability of WEO and organic montmorillonite (OMT) to enhance the high-temperature rheological and self-healing of bitumen binder. Conventional tests and dynamic shear rheology (DSR) test were used to examine the influence of WEO/OMT on the traditional performance and high-temperature rheological properties. Based on a fatigue-healing test, evaluation indicators such as fatigue life recovery (FLR), modulus recovery (MR), and dissipated energy recovery (DER) were chosen to determine the degree of healing of bitumen. The mechanism was revealed by the atomic force microscope (AFM). Finally, a radar chart was employed to analyze the comprehensive properties of WEO/OMT modified bitumen. The results indicate that WEO modified bitumen loses ductility and penetration when OMT is added while increasing softening point and high-temperature performance. Compared to original bitumen, the rutting factor of bitumen modified with 3% WEO and 2% OMT has the most significant increase by 31.2%. The performance of the bitumen binder during fatigue and self-healing is improved by the addition of OMT and WEO. Regardless of the OMT level, bitumen modified with 9% WEO shows a significant improvement in FLR, MR, and DER compared to the original bitumen. In conclusion, the inclusion of WEO/OMT in bitumen offers a fresh approach to developing sustainable pavement materials.