Analysis of Factors Influencing the Low-Temperature Behavior of Recycled Asphalt Mixtures in Seasonal Freeze-Thaw Regions

The use of recycled asphalt mixtures in regions with seasonal freeze-thaw cycles is becoming more popular. However, strict requirements for low-temperature cracking resistance limit their widespread application. This study designed thirteen types of recycled asphalt mixtures to explore factors affecting low-temperature performance in seasonal freeze-thaw regions and potential optimization methods. The three-point bending test assessed the low-temperature cracking performance of mixtures with varying recycled asphalt pavement (RAP) content, asphalt-aggregate ratios, asphalt types, and gradations under both conventional and freeze-thaw conditions. Results show that destructive strain and fracture energy decrease with higher RAP content, but increase with higher asphalt-aggregate ratios and 4.75 mm sieve passing rates. Adding rubber powder significantly enhances both destructive strain and fracture energy. Furthermore, the destructive strain remains insensitive to factors under both and freeze-thaw conditions, while fracture energy effectively distinguishes differences in low-temperature crack resistance. Analysis of variance reveals that RAP content, asphalt-aggregate ratio, asphalt type, and gradation significantly affect fracture energy after freeze-thaw cycles. Optimizing gradation is recommended to improve low-temperature performance of recycled asphalt mixtures in freeze-thaw regions.