Performance of asphalt mixtures containing high reclaimed asphalt pavement and waste steel rolling oil

Reducing costs, dealing with environmental problems, and preserving more natural resources are among the main incentives for reusing asphalt instead of road reconstruction. However, asphalt reuse involves the addition of some modifiers to the asphalt mixture. In this respect, rejuvenators investigated in the previous studies did not perform properly against all failures. Besides, they had problems such as lacking access to the required amount for road construction and high production costs. Regarding the high-temperature resistance and antioxidant properties of the waste steel rolling oil (WSRO), for the first time, the effect of using this lubricant was investigated on the recovery of bitumen aging and the performance of asphalt mixture containing high amounts of reclaimed asphalt pavement (RAP). To this end, the conventional (penetration and softening point) tests and rotational viscosity test were conducted to determine the optimal amount of rejuvenator. In addition, FTIR and FESEM tests were carried out for chemical and morphological investigation. SCB and dynamic creep tests were performed on a balanced mix design to examine the performance against cracking and rutting. Moisture sensitivity was also investigated by performing an indirect tensile test. The results show that a uniform texture was created in the aged bitumen modified with WSRO, and there was a decrease in functional groups that represent the occurrence of aging. Therefore, WSRO can restore aging and improve rutting and cracking performance. Resistance to moisture sensitivity also improved. Overall, the results show a performance improvement in the mixture containing high RAP content mixed with WSRO as a waste rejuvenator. However, more studies encompassing rheological, economic and environmental aspects, are needed to conclude about the practical use of this material.