## Materials and Methods
### Methods
#### 2.2.2 Testing Procedures  
To evaluate and compare the changes in the physical and rheological properties of CRM-, PP-, and TPS-modified asphalt samples with the corresponding parameters of the unmodified asphalt binders to determine the most appropriate additive, the conventional ductility, rotational viscosity (RV), and the dynamic shear rheometer (DSR) tests were performed following the ASTM specifications. At least three samples were measured for each type of modified bitumen; the average was considered the result.  
A Brookfield rotational viscometer apparatus was used to measure the binder viscosity at high temperatures ranging from 60-200 \({}^{\circ}\)C. The test was also conducted to determine the flow features of modified asphalt and assess workability parameters [22]. This test procedure is used to measure the rotational viscosity of the modified asphalt binders at an elevated temperature of 135 \({}^{\circ}\)C. The viscometer spindle and rotor were inserted in the hot binder sample near the edge of the can but were no more profound than the immersion depth mark on the shaft without plugging the vent hole. The rotor was allowed to acclimate to the temperature of the binder for approximately 1 min. The torque on the moving spindle in a sample of heated modified asphalt binder was used to measure the relative resistance to rotation. The torque and speed were used to determine viscosity in entipoises.  
The ductility test was applied to measure the tensile characteristics of the modified and unmodified asphalt materials. The ductility was measured by the distance in centimeters to which the standard specimen elongated before breaking. This occurs when a sample of the materials is pulled at a specified speed and temperature. After the sample preparation, the sides of the mold were removed and the clips were carefully hooked onto the testing machine without causing any initial strain. The pointer was adjusted to zero. The testing machine was then operated and the clips were pulled horizontally at a speed of 50 mm per minute. While the test is being done, the specimen both above and below by at least 25 mm was covered with water in the tank of the testing machine, where the temperature was maintained at 25 \({}^{\circ}\)C continuously within \(\pm\)0.5 \({}^{\circ}\)C [9].  
This method describes the process for determining the toughness and tenacity of modified asphalt binders by using several apparatuses such as container-metal, which is cylindrical in shape, has a flat bottom, and a nominal capacity of 90 mL and nominal inside dimensions of 55 mm in diameter, 35 mm in depth. Tension Head-polished metal has a hemispherical shape like a spider. The testing machine capable of the uniform movement of 50 cm/min had a minimum load capacity of 0.5 kN, sensitive to 0.005 kN. Moreover, a computer was used to automatically measure the three separate areas under the stress-strain curve to determine toughness, tenacity, and cohesiveness. The testing machine was operated to pull the tension head vertically at a speed of 50 cm/minute for the distance of 75 cm. The extension continued until the asphalt column broke, the curve reached zero force, it stabilized at a constant force close to zero, or until the machine's extension limit was reached [23].  
A DSR test was performed to determine an asphalt binder's resistance to permanent deformation (rutting) at medium- and high-temperatures by measuring the rutting parameter (G*/sin(\(\delta\))), phase angle (\(\delta\)), and complex shear modulus (G*) of the modified and unmodified asphalt binders. The temperature corresponding to the minimum amount of G*/sin(\(\delta\)) is known as the failure temperature and is predominantly used to determine the performance grade (PG) of asphalt [24]. The rutting parameter (G*/sin(\(\delta\))), phase angle (\(\delta\)), and complex shear modulus (G*) for the modified and unmodified binders were measured at temperatures of 58, 64, 70, 76, 82, and 88 \({}^{\circ}\)C, respectively, and had a constant loading frequency of 10 rad/s (1.59 Hz).