Laboratory Evaluation of the Performance Properties of Mastics Modified by the combination of Nano-Silica and Gilsonite additives

This research investigates the way nano-silica (NS) and Gilsonite additives affect the performance behaviors of asphalt binders and SMA mixtures. A 60/70 type of asphalt binder, Gilsonite (0, 3, 5, and 7% by the weight of asphalt binder), and nano-silica (0, 2, 4, and 6% by the weight of asphalt binder) are utilized. The physical and rheological behaviors of modified asphalt binders are evaluated by rotational viscosity (RV), dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), bending beam rheometer (BBR), and linear amplitude sweep (LAS) tests. The performance properties of mixtures are evaluated by the application of four-point bending (FPB) fatigue, resilient modulus (Mr), indirect tensile strength (ITS), dynamic creep, and wheel track tests. In order to analyze the data statistically, a two-factor analysis of variance (ANOVA) is evaluated. The rheological behavior test outcomes depicted that Gilsonite utilization and NS additives enhance the rutting and fatigue resistances of asphalt binders. Gilsonite utilization decreases the low-temperature resistance of asphalt binders, while NS improves that. Storage stability test outcomes reveal that Gilsonite utilization enhances the storage stability of asphalt binders. Also, the application of NS leads to enhance phase separation. The MSCR test results demonstrate an enhancement in the high-temperature performance of virgin asphalt binder at different levels of stress by adding Gilsonite and NS. Moreover, NS utilization enhances the rutting resistance of samples. Based on the LAS test, Gilsonite utilization and NS additives enhance the fatigue properties of asphalt binder.