Mechanical Performance of Hot-Mix Asphalt Modified with Porous Nanosilica Aerogels

Asphalt pavements are under extreme strain from high-volume traffic with ultraheavy axle loads, leading to rutting, fatigue, and moisture damage that reduces the useful life of asphalt mixtures. Studies have suggested that nanomaterials can be used in asphalt modification to delay asphalt pavement deterioration. The main objective of this research study is to investigate the influence of nanosilica aerogel (NSA) on the mechanical properties of hot-mix asphalt. The materials employed in the study include the 85/100 penetration grade asphalt binder, limestone aggregate, filler, and NSA additive in varying proportions of 1%, 2%, and 3% by asphalt binder weight. In order to evaluate the mechanical properties of the modified asphalt mixture, Marshall stability and flow, resilient modulus, moisture sensitivity, rutting, indirect tensile fatigue, and semicircular bending tests are performed. The results indicated that the range of 2 to 3% of NSA is a suitable limit for increasing the fatigue life, creep resistance, and strength of asphalt mixtures. Added NSA to asphalt mixtures can lead to a 40% increase in rutting resistance, an 80% increase in fatigue life, and a 12–15% increase in the stability of asphalt mixtures. In conclusion, the increase in aerogel improves the performance of uncracked asphalt mixtures and causes a slight decrease in the load leading to the fracture of cracked samples. Using NSA not only can lead to the creation of thermal, moisture, and sound insulation on the surface but also can lead to an increase in the stability, rutting resistance, and fatigue life of the asphalt mixture.