Pre-treatment of ground tire rubber is emerging as a popular method to incorporate rubber particles in dense-graded asphalt mixtures. This study investigates the effects of a chemically engineered Dry-Process Ground Tire Rubber (DP-GTR) modification in asphalt binders and mixtures. The DP-GTR is comprised of rubber particles measuring 400 to 600 µm in diameter (minus #30 mesh) coated with a non-elastomeric liquid. No change in aggregate gradation is necessary in DP-GTR modification of asphalt mixtures. In this study, the effects of DP-GTR modification on binder properties were measured by dynamic shear rheometer, Multiple Stress Creep and Recovery (MSCR), and bending beam rheometer tests. Additionally, mixture properties measured by three cracking tests: Disk-shaped Compact Tension (DC[T]) test, Illinois Flexibility Index, and indirect tensile asphalt cracking test and one rutting test (Hamburg wheel track test) were evaluated. Results showed: (a) 10–12°C bump on binder high temperature performance grade with 10% DP-GTR modification by weight of binder; (b) improvement in non-recoverable compliance in MSCR test indicated higher rut resistance; (c) increase in DC(T) fracture energy at low temperatures; (d) decrease in rut depth; and (e) decrease in flexibility index and cracking test index. Field performance of the chemically treated DP-GTR sections located in different states was examined to address discrepancies observed in the cracking tests. The cracking and rutting performance of all the field sections was good-to-excellent, suggesting that some of the currently popular simple cracking tests may not be able to properly assess the cracking resistance inherent in GTR-modified asphalt mixtures.

磨碎轮胎橡胶的预处理作为将橡胶颗粒掺入致密渐变沥青混合物中的一种流行方法正在兴起。这项研究调查了化学工程干法地面轮胎橡胶（DP-GTR）改性对沥青粘合剂和混合物的影响。DP-GTR由直径400至600 µm（负＃30目）的橡胶颗粒组成，上面涂有非弹性液体。沥青混合料的DP-GTR改性无需改变骨料的级配。在这项研究中，通过动态剪切流变仪，多重应力蠕变和回复率（MSCR）和弯曲梁流变仪测试来测量DP-GTR改性对粘合剂性能的影响。此外，混合物的性能可通过以下三个裂化测试进行测量：盘状紧凑拉伸（DC [T]）测试，伊利诺伊州柔韧性指数，并进行了间接拉伸沥青开裂试验和一项车辙试验（汉堡轮迹试验）。结果表明：（a）粘合剂高温性能等级在10–12°C时发生颠簸，DP-GTR的改性量为粘合剂的10％；（b）MSCR测试中不可恢复的依从性的改善表明较高的耐车辙性；（c）在低温下增加DC（T）断裂能；（d）车辙深度的减少；（e）柔韧性指数和裂化试验指数的降低。对处于不同状态的化学处理过的DP-GTR切片的现场性能进行了检查，以解决在裂化测试中观察到的差异。所有领域的开裂和车辙性能都非常出色，