Investigation of the use of waste oil in recycled asphalt mixtures with regard to sustainability and structural performance criteria

The rapid growth of the global population has made waste management a critical issue on a global scale. In this context, the concepts of recycling and sustainability have come to the forefront with their environmental, economic, and social dimensions, requiring holistic approaches. The efficient use of limited natural resources, combined with the responsibility to leave a livable environment for future generations, has made the reuse of waste materials vitally important. This study investigates the potential use of waste engine oil (WEO) and waste vegetable oil (WVO), both of which have environmentally harmful effects, as additive materials in the asphalt industry. Reclaimed asphalt pavement (RAP) contents were determined as 0%, 10%, 30%, and 50%, and for each mixture, fundamental engineering parameters such as bulk specific gravity, water absorption, stability, flow, and Marshall quotient were analyzed. Based on the obtained results, 30% RAP was identified as the optimal ratio. Mixtures were then prepared by adding 5% and 10% of WEO and WVO separately at this RAP level, and their performances were compared. The experimental results demonstrated that the addition of waste oils improved the engineering properties of hot mix asphalt and contributed to preventing bitumen aging. The best performance was achieved with 10% WEO and 5% WVO. This study offers an innovative approach to the utilization of waste oils, contributing both to the reduction of environmental pollution and the enhancement of asphalt performance. Furthermore, it promotes the sustainable use of materials in the construction sector. Keywords: Bitumen Aging, Waste Engine Oil, Waste Vegetable Oil, Reclaimed Asphalt Pavement, Recycling