Sustainable production of aging-resistant bitumen: Waste engine oil modification

Abstract

Using waste engine oil (WEOIL) within bituminous binders might be one of the most energy-efficient and sustainable means of producing aging-resistant bitumen due to the antioxidative properties of WEOIL. In this paper, the use of WEOIL to obtain aging-resistant bitumen and its optimum rates for short and long terms were investigated. In this regard, a base bitumen was modified with WEOIL in certain rates ranging from 1% to 5% by weight of bitumen. Then base and oil-modified bitumen samples were subjected to aging. To define the changes in rheological properties of bitumen based on rutting, fatigue, and thermal cracking resistance, dynamic shear and bending beam rheometer tests were performed on each sample. Furthermore, an aging index (AI) analysis was performed for both the short- and long-term aging conditions to express the effect of WEOIL on aging resistance of the bitumen. According to the AI analysis, short-term-aging-resistant bitumen is obtained by adding 3.5% WEOIL to the base bitumen, while a 5.8% contribution rate is required to avoid the long-term aging effect. Moreover, the increase in rate of WEOIL content improved the low-temperature cracking resistance. Consequently, utilizing WEOIL for production of aging-resistant bitumen can provide environmental and economic benefits based on conservation of natural resources and waste recycling.