## 2 Experimental Design
### Evaluation of Binder  
Evaluation of Superpave Binder Properties  
Evaluating the performance of asphalt binders at various phases of their lifespan is crucial for guaranteeing the resilience and endurance of road infrastructure. An exhaustive examination was carried out utilizing three standardized test methods in accordance with the American Association of State Highway and Transportation Officials (AASHTO): the viscosity test (AASHTO T 316) [27], the Dynamic Shear Rheometer (DSR) test (AASHTO T 315) [28], and the Bending Beam Rheometer (BBR) test (AASHTO T 313) [26]. The Brookfield Rotational Viscometer was used to perform a rheological examination through a viscosity test. Viscosity measurements were conducted on a standardized 10.5 g sample of each modified binder type using a number 27 spindle. Assessments were conducted at two separate temperatures, specifically 135 \({}^{\circ}\)C and 180 \({}^{\circ}\)C, to encompass a wide variety of circumstances that binders can encounter. This method offers significant insights into the rheological properties of binders, which are crucial for achieving optimal blending and compaction procedures in construction. The purpose of the DSR test was to measure the viscoelastic properties of the binders in their original condition as well as after undergoing two aging processes--short-term aging (RTFO) and long-term aging (RTFO + PAV). The test was conducted at a frequency of 10 radians per second, which is approximately equivalent to 1.59 Hz. This frequency is considered optimal for accurately representing the material's shear-related behaviors in real-world conditions. The values of Complex Shear Modulus (G*) and Phase Angle (8) were calculated. The value G*/sin\(\delta\) was specifically computed to evaluate the material's ability to withstand rutting, whereas G*. sin\(\delta\) was evaluated at 25 \({}^{\circ}\)C to determine its susceptibility to fatigue cracking. The BBR test was conducted to assess the performance of the binders at low temperatures, utilizing the leftover samples obtained from the RTFO + PAV process. Creep stiffness (S) measurements were conducted on modified binder beams with dimensions of 125 \(\times\) 6.35 \(\times\) 12.7 mm at a temperature of \(-12\)\({}^{\circ}\)C to imitate cold-weather conditions. A 100 g force was exerted on the beam, and the displacement at the center of the beam was measured continuously for a duration of more than 60 s. This test is essential for comprehending the behavior of the binder in relation to thermal-induced stresses, particularly its sensitivity to cracking. The tests were performed three times each, and the average of the findings was calculated to ensure statistical robustness and reproducibility. This comprehensive evaluation technique facilitated a thorough comprehension of the performance characteristics of asphalt binders during different stages of their lifespan. The MSCR test is a method used to measure the recovery of multiple stresses in a material. The Multiple Stress Creep Recovery (MSCR) test was performed on a modified asphalt binder utilizing Dynamic Shear Rheometer (DSR) equipment in accordance with the AASHTO TP 70 guidelines [29]. The rheological properties of the binder were evaluated by conducting this test on both the unaged and short-term aged (RTFO) samples. The MSCR test was conducted at two distinct stress levels, specifically 0.1 kPa and 3.2 kPa. This involved subjecting the material to cycles of creep loading and unloading, with periods of 1 s and 9 s, respectively. Each stress level was subjected to a total of ten cycles. The test produces two crucial parameters: the nonrecoverable creep compliance (J\({}_{\text{nr}}\)) and the percentage recovery (% recovery). These measurements are used as quantitative tools to assess the susceptibility of asphalt binders to rutting. The nonrecoverable creep compliance (J\({}_{\text{nr}}\)) is determined by dividing the nonrecoverable shear strain by the applied shear stress.