Effect of nano silica on the performance of modified crumb rubber bitumen and asphalt mixtures

The performance of CR-modified bitumen is mainly influenced by compromising on storage stability, elasticity, and high-temperature rutting. The primary target of this research is to address these concerns by incorporating nano-silica (NS) at five different dosages, i.e., 1–5% by weight of bitumen into the controlled bitumen (CR-10%) using a wet mixing technique. The characterization of the nano-CR formulations was evaluated using Fourier Transform Infrared spectroscopy (FTIR). The physical interaction between the NS and controlled bitumen enhanced the storage stability, elasticity, and high-temperature performance. The nano modification with controlled bitumen improved the engineering properties, thermal susceptibility, high-performance grading (PG), and rheological characteristics. The comprehensive asphalt test results concluded that high NS dosage provides appropriate moisture damage, rutting, and fatigue performance. The statistical analysis validated that the optimum dosage of NS-5% provides improved elasticity, storage stability, and rutting resistance by 10%, 48%, and 11%, respectively. These findings confirm that NS has significant potential for improving CR-asphalt performance, which is a promising future additive for practical applications in pavement engineering.