Waste frying oil modified bitumen usage for sustainable hot mix asphalt pavement

Asphalt concrete is composed primarily of aggregate and asphalt binder. By volume, a typical Hot Mix Asphalt (HMA) mixture is about 85% aggregate, 10% asphalt binder, and 5% air voids. Bitumen is very important as a binder material in asphalt concrete. However, the cost of the bitumen is relatively high. For this reason, highway professionals are looking for modifiers to decrease the bitumen content used in the asphalt pavement. In this study, waste frying oil (WFO) is used as a modifier to modify the bitumen. As a result, by adding WFO into the bitumen, optimum binder content of a mixture was decreased from 5.125% down to 4.575%. So that, roads constructed with WFO modified bitumen are sustainable because of decreasing the bitumen rate used in the mixture. In addition, softening point of the modified bitumen is decreased (up to 82%) while the penetration value is increased (up to 240%) by modifying the bitumen with WFO. The tensile strength ratios of the modified asphalt specimens are all above the minimum specification limit, 80%. Finally, required temperature for fast self-healing is decreased by modifying the bitumen with WFO. Specimens prepared with WFO modified bitumen are healed compared to the reference specimen.