The Effect of Lignin and Soybean Oil on Rheological Behavior of Asphalt Binder

In this study, an attempt has been made to investigate how the rheological behaviors of bitumen are affected by the use of lignin and soybean oil. In the current research, lignin (3%, 5%, 7% by weight of bitumen) and soybean oil (5% by weight of bitumen) were added to modify two main types of bitumen (AC 60-70 and AC 85/100). The performance evaluation of different bitumen was evaluated by examining their physical and rheological behavior by penetration tests, ductility, linear range sweep, multiple stress creep recovery, dynamic shear remoter, rotational viscosity and softening point tests. The results of rheological behaviors showed that the use of lignin additive increases the softening point and decreases the degree of penetration. The use of lignin reduces the low-temperature strength of the bitumen, while oil improves the low-temperature strength of the bitumen. The results of the multiple stress creep recovery (MSCR) test with the addition of lignin showed an increase in the high yield temperature of virgin bitumen at different stress levels. While the use of oil reduces the creasing strength of the sample. According to the results of the linear range sweep (LAS) test, the use of lignin additive reduces the fatigue properties of bitumen. While soybean oil strengthened it.