Crumb Rubber Modified Bitumen for Flexible Pavement: A Comprehensive Review

Crumb rubber modified bitumen (CRMB) has gained significant attention as a sustainable and performance-enhancing binder for flexible pavements. This comprehensive review consolidates knowledge on the production methods (wet process, dry process, and terminal blending), influence of crumb rubber on physical and rheological properties of bitumen, and the consequent improvements in pavement performance including resistance to rutting, fatigue cracking, low-temperature cracking, and aging. The review also examines the Indian regulatory framework under IS 15462:2019, the environmental and economic advantages of incorporating waste tire rubber, and the challenges hindering widespread adoption. Findings from the literature consistently demonstrate that CRMB outperforms conventional bitumen in terms of high-temperature stability, elastic recovery, and long-term durability. The review identifies research gaps and provides direction for future work towards optimized mix designs and field performance evaluation in Indian climatic conditions.