Comparison of permanent deformation and fatigue resistance of hot mix asphalts prepared with the same performance grade binders

In this study, the volumetric properties, Marshall stabilities, the indirect tensile stiffness moduli, and the fatigue and permanent deformation strengths of hot mix asphalts prepared with the same performance grade binders in accordance with Superpave method at optimum binder contents were comparatively investigated. In addition, the effect of bitumen modification using SBS on the mechanical characteristics of the mixtures was evaluated. Dynamic creep and indirect tensile fatigue tests were conducted at two distinct stress levels and three different loading periods. As the binder tests, it was determined that the modified bitumen obtained by adding of 3% SBS by weight into the B160/220 binder yielded the same level of performance with the B70/100 bitumen. It was also found that using 3% SBS by weight for the purpose of bitumen modification enhanced the desired properties of the mixture to a significant degree. It was observed that the best performance belonged to the mixtures containing B70/100 bitumen, while the worst performance was found for the mixtures made from B160/220 bitumen. Additionally, although the mixtures prepared by the same performance grade binders in accordance with the Superpave system were expected to behave similarly, it was found that they differed considerably with respect to their stiffness, tensile strength and strength against permanent deformation.