The incorporation of rejuvenators in asphalt technology has emerged as a promising sustainable method for rejuvenating the properties of aged modified asphalt binder. The use of isocyanate compounds as active reagents for rejuvenating aged SBS-type asphalt binders presents notable limitations. Firstly, these compounds are associated with high vapor pressures, making them potentially hazardous and volatile, which poses risks to environmental safety and worker health during application, thereby restricting their widespread adoption. Secondly, the literature indicates a critical gap in the effectiveness of existing rejuvenation agents, particularly in restoring the performance of SBS-type asphalt binders at low temperatures. This study evaluates the combined effects of sunflower oil and diallyl phthalate (DAP) as low-risk rejuvenators to enhance the functional characteristics of aged high-viscosity modified asphalt (HVMA). Sunflower oil restored lost volatiles, while DAP repaired fractured SBS polymer chains. The research involved formulating rejuvenators with optimal concentrations of sunflower oil and DAP, followed by a range of physical, rheological, and chemical tests to evaluate the performance-related properties of the rejuvenated HVMA. The results showed a notable improvement in both high-temperature and low-temperature performance, as well as in the chemical properties of aged HVMA. The recovery rate of the high-performance material was determined to be 96.8 % using the multiple stress creep recovery test. Low-temperature results indicated that as DAP content increased, the low cracking temperature improved, suggesting a recovery rate of 98.55 %. Furthermore, chemical analyses revealed recovery rates of 89.8 % and 90.3 % for Fourier transform infrared spectroscopy and gel permeation chromatography tests, respectively. These findings indicate that the synergistic use of sunflower oil and DAP effectively restores the properties of HVMA. The application of this rejuvenation method not only enhances pavement performance but also promotes the use of biodegradable materials in asphalt technology, ensuring a more sustainable approach to pavement maintenance and construction.
