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The current study aims to examine the physical and rheological properties at the high-temperature range of 52, 58, 64, 70, 76, and 82°C, utilizing adjusted asphalt binders. Three kinds of asphalt modifiers were selected such as styrene-butadiene-styrene, ethylene vinyl acetate, and end of life tires. The selected additives were implemented with different contents ranging from 4% to 7% by the weight of neat asphalt. Various test methods have been established, such as ductility, viscosity, microscopic inspection, and dynamic shear rheometer experiments. Results proved that the percentage decrease in ductility was 93%, 91%, and 88% with regard to the adding of the end of life tires (ELTs), ethylene vinyl acetate (EVA), and styrene-butadiene-styrene (SBS) additives, respectively. Outcomes also confirmed that viscosity was boosted from 0.411 Pa.s to 1.249, 1.0986, and 0.9785 Pa.s after adding 7% of ELTs, 7% of EVA, and 7% of SBS, respectively. The rutting parameter and complex shear modulus increased after modification, indicating the excellent performance of asphalt. The conclusions confirmed that the ELTs have fewer agglomerates and have good compatibility before ageing and excellent compatibility after the ageing process. Thus, the ELTs are deemed as efficient dispersion additive for avoiding separation during the storage and handling of the asphalt binder. Lastly, ELTs were accepted as the best enhancer for their positive influence on physical and rheological characteristics, which means higher quality amended bitumen would give higher resistance to permanent deformation.

The overall objectives of this study were to determine the most appropriate additive for improving the physical properties and the medium- and high-temperature performances (mechanical performance) of asphalt binders. Three different types of modified binders were prepared: crumb rubber modifier (CRM), polypropylene (PP), and tafpack super (TPS), which had concentrations of 2%, 3%, 3.5%, and 4% by weight of asphalt binder, for each modifier. Their physical and rheological properties were evaluated by applying various tests such as ductility, rotational viscosity, toughness, and tenacity, as well as the dynamic shear rheometer (DSR) test. As a result, the physical properties of the modified bitumen binders were compared, as were the medium- and high-temperature performances (mechanical performance), which had temperatures of 58, 64, 70, 76, 82, and 88 °C, respectively. This was how the most appropriate modifier was determined. The results demonstrated that the asphalt binder properties significantly improved by utilizing CRM followed by PP and TPS modifiers. The increase in the rutting parameter (G*/sin(δ)) after asphalt modification indicated its excellent performance at both medium- and high-temperatures. Lastly, the CRM was determined as the most preferred additive because of its positive effect on the physical properties and enhancement of the medium- and high-temperature performance (mechanical performance).