Effect of low-content crumb rubber modification on the performance of bitumen and asphalt

The performance of flexible pavements is greatly influenced by rutting, fatigue, and durability, leading to premature failures under environmental conditions. The limitations of traditional bitumen in flexible asphalt pavements are due to the significant rise in traffic loads and volumes. The reason for incorporating tire waste into bitumen is its incredible qualities and economical price as a bitumen modifier. The quality of crumb rubber (CR)-modified bitumen mainly depends on the concentration of low-content CR dispersed into the base bitumen. The primary target of this research is to modify the bitumen with low-content CR to improve the thermal properties, rheology, rutting resistance, fatigue resistance, and moisture-damaged performance. The three concentrations, i.e., 5%, 10%, and 15% of CR, were selected based on extensive preliminary trials when dispersed in conventional 60/70 penetration grade bitumen. The consistency and mixture test results concluded that the optimum dosage of CR-10% provides a 20% improvement in thermal performance, a 15% increase in rheological stability, a 25% enhancement in rutting resistance, a 30% boost in fatigue resistance, and a 10% reduction in moisture damage susceptibility. The inclusion of CR makes rubberized asphalt an attractive and effective solution for highway construction, aligning with sustainable construction practices. The findings demonstrate that low-content CR-modified asphalt improved the durability of asphalt mixtures against moisture-induced damage and other benefits, such as reduced cracking and maintenance requirements. The CR technology led to a significant subsidization in the environmental impact of asphalt paving from 5 to 10% compared to standard paving applications.