Using bio-oil as a rejuvenator for asphalt extracted from reclaimed asphalt pavement

Every year, huge quantities of asphalt pavement resulting from road rehabilitation are crushed. To address the threat of waste accumulation and achieve a sustainable environment, the world has turned to recycling these asphalt wastes by treating them with renewable materials for reuse. In this research, bio-oil, which is a green liquid composed of oils extracted from biomass (corn oil, hill oil, sunflower oil, soybean oil, rapeseed oil and vegetable oil), was used. Many studies have employed different types of bio-oil as rejuvenators, showing good results for aged asphalt treated with bio-oil. Therefore, this type of bio-oil was used to demonstrate its effect on the physical condition and physical properties of bio-oil. One of the characteristics of the reclaimed asphalt was tested by adding bio-oil in different weight percentages (1%, 2%, 3% and 4%) to a blend of 70% virgin asphalt and 30% reclaimed asphalt to determine the ideal bio-oil proportion. Physical tests (penetration, softening point, ductility and viscosity) were conducted on the mixture. The results showed that adding bio-oil at an optimum rate of 1.31% to the mixture increased penetration and ductility by 15.6% and 34%, respectively; reduced the softening point by 7% and decreased viscosity at 135 °C and 165 °C by 33% and 58%, respectively. According to the results, aged asphalt can be renewed to a condition similar to virgin asphalt, offering both environmental and practical benefits by reducing waste.