With growing emphasis on environmental protection and sustainability in highway construction, the high mixing and compaction temperatures of styrene-butadiene-styrene (SBS)-modified asphalt have raised concerns regarding energy consumption and pollutant emissions. Sasobit, a warm-mix additive with a melting point of 99 °C, effectively reduces asphalt viscosity and construction temperatures while enhancing high-temperature performance; however, it may adversely affect low-temperature crack resistance. To address this challenge, this study developed low-dosage Sasobit–SBS composite asphalt incorporating aromatic oil and crumb rubber to reduce production temperatures while maintaining performance. Evaluations on binder properties and mixture performance showed that Sasobit effectively lowers mixing temperatures and preserves rutting resistance, while external modifiers, especially crumb rubber, significantly enhance low-temperature crack resistance (by 24%) and fatigue life (by 50%). Moreover, the crumb rubber formulation reduced production costs by 11% compared to conventional SBS asphalt, demonstrating a practical and cost-effective strategy for improving durability in cold regions.

1. Various environmental and economic challenges have influenced the construction industry in recent years. As a result, reclaimed asphalt pavement (RAP) with high content has been increasingly rec...

Owing to certain inherent deficiencies in their properties, fine reclaimed asphalt pavement (RAP) particles have not yet been widely reused worldwide, resulting in significant environmental pollution and economic waste. Currently, a diverse array of design methods for asphalt mixes has been proposed. These methods can exert a varying influence on the degree of blending (DoB) and the performance of recycled hot-mix asphalt containing fine RAP particles, and some methods may be better suited for recycling fine RAP particles. However, the specific effects and differences among these various methods have yet to be fully revealed. Therefore, this research comprehensively explored these behaviors. Four distinct mix design formulations were investigated: the dense-graded Asphalt Concrete Group (Group AC), the Stone Mastic Asphalt Group (Group SMA), the High-modulus Asphalt Concrete Group (Group HMAC), and the rejuvenator-modified Asphalt Concrete Group (Group AC+Re). It can be found that the DoB and performance varied across different groups. The DoB spanned from 69% to 82%, with Group SMA showing the highest and Group HMAC exhibiting the lowest. The tensile strength ratio (TSR) of Group AC performed only 73.7%, failing to meet the specification threshold; nevertheless, this shortfall can be compensated by employing alternative methods or adding rejuvenator. Group HMAC exhibited the highest splitting-tensile strength and fracture energy. In addition, the incorporation of rejuvenator can enhance most performance of mixes. Some findings may provide a new perspective for the application of fine RAP particles.