Xiaoming Li, Chuanxu Li, Liqiang Xi, Yudong Zhu, Panpan Dong, Peitong Chen, Fan Zhang, Fayong Yang
To maximize the resource utilization of waste tires, this study systematically investigates the rheological degradation, phase stability, and micro-evolution mechanisms of high-content (30 wt%-50 wt%) desulfurized rubber modified asphalt (HDRA) under short-term and long-term thermo-oxidative aging by rotating film oven test and pressure aging vessel test (RTFOT and PAV). Through multi-scale approaches including DSR, BBR, TD-GC-MS, FTIR, and microscopic morphology characterizations (SEM/FM), the macroscopic rheology, full-lifecycle volatile organic compound (VOC) emissions, and morphological responses were quantitatively evaluated. The results reveal that the 50% HDRA exhibits a unique "aging self-adaptive" characteristic: thermo-oxidative exposure triggers deep swelling and cross-linking of the dense rubber network, which substantially reinforces high-temperature elasticity while restricting particle migration, thereby completely reversing the initial high-temperature segregation susceptibility. However, the hyper-dense skeleton introduces a low-temperature "rheological trade-off"; long-term aging restricts the internal free volume, significantly diminishing the stress relaxation capacity under sub-zero conditions. Furthermore, gaseous molecule tracking and chemical index analysis confirm a microscopic "sacrificial protection" mechanism. The early-stage intensive depolymerization and devulcanization of the rubber network consume thermo-oxidative energy and physically and chemically shield the base asphalt from profound hardening. Consequently, as aging deepens, the full-lifecycle failure mode transitions from conventional matrix embrittlement to severe polymer-asphalt interfacial debonding and phase homogenization. This study provides a novel theoretical foundation for the precise design and eco-friendly application of ultra-high content solid-waste rubber in long-life pavement materials.