Abstract
The restricted availability of raw materials underscores the significance of recycling asphalt materials that have reached the end of their service life, facilitating their reuse with additives for economic and sustainability benefits. The study includes both empirical investigations and numerical analyses. Empirical studies were conducted in four stages to evaluate the binder and mixture. First, the rheological properties of binders obtained from various sources were assessed in both unmodified and modified states. Second, the binders were subjected to different levels of aging. Third, the presence of additives in the binders was investigated. In the final stage, the analysis of asphalt pavement layers was conducted using the finite element method (FEM) for both modified and unmodified binders. Performance tests were carried out to evaluate the binder's properties, and physical examinations were conducted to compare these properties. The binders were tested under both unaged and aged conditions using linear amplitude sweep (LAS), frequency sweep (FS), multiple stress creep recovery (MSCR), and bending beam rheometer (BBR) tests. The results indicated that aging increased the stiffness of the binders, regardless of their source. Additionally, the introduction of a rejuvenator reduced the binder's stiffness, particularly at low temperatures. Findings showed that the growth rate (GR) and rutting parameters increased with binder aging, while the frequency decreased. The R(2) value of 0.92 demonstrates a strong correlation between the parameters. Polymer-modified binders demonstrated superior deformation resistance and higher stiffness stability. Overall, aging reduced asphalt flexibility, whereas modified binders improved long-term pavement deformation performance.