Investigating the rutting behavior of asphalt binders modified with high-dense polyethylene and gilsonite at high temperatures

In recent years, in order to improve the functional properties of asphalt binder, researchers have turned to modify asphalt binder using various materials such as chemicals, polymers, nanomaterials, etc. Rutting is one of the most important and common failures that occur in asphalt pavement. In order to investigate the effect of additives on rutting failure, two types of modifiers including gilsonite (natural mineral bitumen) and high dense polyethylene (HDPE) have been used in this study. For this purpose, pure bitumen 85/100, with three amounts of 4, 8, and 12 percent by weight of bitumen with gilsonite and three amounts of 2, 4, and 6 percent by weight of bitumen with HDPE, has been mixed with a high shear mixer. By conducting a dynamic shear rheometer (DSR) test at 4 temperatures of 58, 64, 70 and 76 degrees Celsius, the effect of additives on asphalt rutting behavior has been investigated. Based on the DSR test results, it can be said that the short-term aging of modified asphalt binder has a significant effect on the amount of rutting based on the G*/sinδ parameter. The results show that the lowest amount of rutting parameter (G*/sinδ) at temperatures of 58, 64, 70 and 76 degrees Celsius in pre-aging conditions is related to asphalt binder modified with 4% HDPE. But among the aged samples, the asphalt binder sample containing 6% HDPE had better rutting behavior. The rutting behavior of asphalt binder modified with gilsonite also shows that with the increase of gilsonite percentage up to 12%, the rutting resistance rate of bitumen has also increased and its effectiveness is more significant in aged samples.