Advancing asphalt binder performance through nanomaterial and polymer modification: Experimental and statistical insights

• Effects of NS, NHL, SBS, and EVA on asphalt binder performance were evaluated. • Tests included basic properties, PG grading, MSCR, LAS, and microstructural analysis. • ANOVA confirmed the statistical significance of binder modification. • SBS at 6 % optimized rutting resistance, while 4 % improved fatigue life. • SEM analysis revealed modifier dispersion and binder morphology changes. The rapid increase in vehicle numbers, traffic speed, and axle loads has considerably shortened pavement lifespan and escalated maintenance costs. To address these challenges, modifying asphalt binders with nanomaterials and polymers has become essential for enhancing pavement durability and performance. In this study, an extensive experimental program was conducted to evaluate the effects of inorganic nanomaterials; nano-silica (NS) and nano-hydrated lime (NHL) and polymer modifiers (elastomeric SBS and plastomeric EVA) at varying dosages (2 %, 4 %, and 6 % by weight of asphalt binder) on asphalt binder properties. The investigation included conventional physical properties, high-temperature performance grading (PG), Multiple Stress Creep Recovery (MSCR), and Linear Amplitude Sweep (LAS) tests. Additionally, Scanning Electron Microscopy (SEM) was employed to assess the microstructural characteristics of modified binders. To statistically validate the findings, ANOVA analysis was performed to determine the significance of each modifier on the tested properties. The results demonstrated that SBS-modified binders exhibited superior rutting and fatigue resistance, with 6 % SBS being the most effective for high-temperature performance and 4 % SBS providing optimal fatigue life. Nanomaterial modifications also improved binder stiffness and high-temperature stability, with NHL performing better than NS. However, EVA showed limited enhancement in rutting and fatigue resistance. Overall, the findings confirm that polymer modification, particularly with SBS, is the most effective approach for improving asphalt binder performance under varying traffic and environmental conditions.