Performance of High-Elastic Modified Asphalt for Paving-Type Recycled Stress Absorption Layer

To enhance the performance of recycled high-elastic modified asphalt binder and achieve high-quality and high-content utilization of RAP fine materials in the design of stress absorbing layers, a highly permeable recycled high-elastic modified asphalt (ZGT-R) was prepared by adding SBS modifier, light component oil, and penetrant to replenish the degraded SBS molecules and reduce intermolecular forces. The conventional properties, elastic recovery, degree of fusion between new and aged asphalt, rheological properties, and micro-modification mechanism of ZGT-R and ordinary recycled high-elastic modified asphalt before and after the addition of the rejuvenator were analyzed. The results show that, compared with the two types of ordinary recycled high-elastic modified asphalt, the penetration and ductility of ZGT-R increase by 51.6% and 22.4%, respectively, and the elastic recovery also improves, demonstrating excellent anti-reflection cracking performance and regeneration effect. The higher viscosity ratio also proves that ZGT-R breaks through the limitation of the degree of fusion between new and aged asphalt. In terms of rheological properties, when the aged asphalt content is between 35% and 55%, ZGT-R exhibits lower temperature sensitivity and stress sensitivity and overall shows better anti-deformation ability. Regarding the micro-modification mechanism, the SBS in ZGT-R exhibits a dense spatial cross-linked network structure, proving the full swelling and diffusion of SBS and providing a new idea for the design of high-elastic modified asphalt for recycled stress absorbing layers.