Sustainable Cold Mix Asphalt: A Comprehensive Review of Mechanical Innovations, Circular Economy Integration, Field...

Climate change presents a major challenge of the Anthropocene, with construction activities contributing about 23% of global CO₂ emissions. Pavement engineering, particularly hot mix asphalt (HMA) production, generates roughly 350 million tons of CO₂ annually due to high-temperature processes. Cold mix asphalt (CMA) has emerged as a sustainable alternative, reducing energy use by 35-50% and emissions by 40-60% through ambient-temperature production with emulsified or cutback binders. Although early CMA formulations suffered from low mechanical strength, long curing times, and poor moisture resistance, recent innovations such as nano-modified binders, polymer and rubber additives, and optimized RAP utilization have greatly improved performance. Modern CMA now achieves enhanced rutting resistance (>4000 cycles/mm), moisture resistance (TSR > 85%), and rapid strength gain (24 h). This review synthesizes findings from over 160 studies to examine composition, property relationships, performance evaluation methods, life-cycle comparisons, and global field validations. Furthermore, it highlights gaps in predictive modeling, mix-design standardization, and circular economy integration to support the evolution of next-generation CMA technologies aligned with UN Sustainable Development Goals 9, 11, and 13.