Synergistic Effect of Nanosilica Particles on Rutting and Cracking Resistance of Polymer Modified Asphalts

In many regions worldwide, modified binders have become the standard for enhancing pavement performance. To address the limitations of polymer-modified asphalts, nanomaterials, such as nanosilica, have been widely adopted as asphalt binder modifiers. This study explores the synergistic effects of nanosilica particles in improving the performance of various polymer-modified asphalts. Two polymers, polyethylene (PE) and polypropylene (PP), were incorporated into the asphalt binder at varying concentrations. Fourier-transform infrared (FTIR) spectroscopy was used to investigate the chemical interactions between the nanosilica and the polymer-modified binders. Performance properties, including fatigue life at different temperatures and resistance to rutting deformation, were evaluated. Response Surface Methodology (RSM), based on a Box-Behnken Design, was utilized to develop performance predictive models and optimize the overall asphalt mixture. Additionally, the reliability of the nano-modified polymer asphalt binders was assessed using parametric survival analysis. The results revealed a significant improvement in fatigue life for nano-modified polymer asphalts compared to control mixtures, indicating greater resistance to fatigue cracking under high-stress conditions. Rutting deformation was reduced by nearly 50% in nano-modified mixtures compared to standard polymer-modified asphalts. Moreover, polypropylene-based nano-modified asphalts demonstrated superior rutting resistance compared to their PE counterparts, highlighting polypropylene's greater ability to enhance mixture stiffness. Reliability analysis further confirmed that PP nano-modified asphalts outperformed PE nano-modified asphalts at all strain levels. The validation of the RSM model showed a strong correlation between the predicted and experimental results, with prediction errors under 7%, demonstrating the model's robustness.