Evaluation of hot mix asphalt and binder performance modified with high content of nano silica fume

This research aims to evaluate the mechanical properties of hot asphalt mixtures prepared using modified asphalt binders with various contents of nano-silica fume (NSF). The modification to virgin bitumen is done by shear mixing with NSF at low contents (2, 4, 6, and 8%) and high contents (20, 30, 40, and 50%) with bitumen weight. The homogeneity of the modified asphalts was assessed using Scanning Electron Microscopy. The rotational viscosity, softening point, and penetration tests were used to evaluate the rheological-physical properties of the modified asphalt binders. The stiffness, moisture damage, rutting, and fatigue of the hot mixes prepared with NSF-modified binders were evaluated using Marshall, indirect tensile strength, and double punching tests. The results showed a significant improvement in the rheological-physical properties of the modified binders with high content compared to low content of NSF. Therefore, the modified binders with 30%, 40%, and 50% of NSF were selected to prepare NSF-modified mixtures. The results showed that asphalt mixtures incorporating 30, 40, and 50% NSF-modified binders were more resistant to moisture damage, rutting, and fatigue cracking compared to the control mixture. The novelty in this research is to produce a modified asphalt mixture with two-thirds a quantity of bitumen while achieving a high performance compared to the control mixture