Integration of warm mix technology and high crumb rubber content for enhanced asphalt treated base material

Incorporating high-content crumb rubber (CR) into asphalt binders offers a cost-effective approach by partially replacing base asphalt, and the resulting cost savings can offset the additional expenses of warm mix asphalt (WMA) additives. This study explores the integration of WMA technology into rubber asphalt with high CR content to achieve enhanced binder performance without increasing overall material costs. Various WMA additives were evaluated based on their viscosity-reducing effects and cooling potential, and optimal dosages were determined. The influence of these additives on the physical and rheological properties of rubber asphalt was systematically analyzed. Furthermore, a warm mix rubber asphalt treated base (ATB) mixture was developed through optimized gradation design and compaction methods, based on mixture volumetrics and pavement performance requirements. Performance evaluations, particularly focused on anti-reflection cracking resistance, were conducted. The results show that the viscosity reduction is more effective when WMA additives are introduced during the breeding stage, with greater effects at higher dosages. Additionally, aggregate gradation optimization based on fractal theory contributes to improved mechanical performance, and the Marshall compaction method outperformed the gyratory method in terms of compactness and bearing capacity. The final warm mix rubber asphalt ATB mixture demonstrated excellent mechanical performance and superior resistance to reflective cracking, along with improved low-temperature crack resistance and reduced temperature sensitivity. This study provides practical guidance for the large-scale application of warm mix rubber asphalt as a sustainable and cost-effective flexible base material.