The assessment of effects of hydrated lime usage as filler on the performance of mixtures prepared with modified bitumen

In this thesis study, effects of 2% hydrated-lime usage as filler on the performance of hot mix asphalt prepared with pure and modified binders was examined. In the study, styrene-butadiene-styrene (SBS), Iranian Gilsonite (IG) and American Gilsonite (AG) were used as additives in bitumen. After conducting Superpave binder experiments, 4.0% of SBS, 11.0% of American Gilsonite and 10.0% of Iranian Gilsonite in terms of bitumen weight were decided to be used. For mixtures without hydrated lime, design binder contents were determined according the Superpave method. For mixtures containing hydrated lime, binder contents which are specified for mixtures without hydrated lime regarding to binder type were used. Mixtures with and without hydrated lime were identified to satisfy criteria for specification. Mixture samples were subject to Marshall stability and flow, resistance to moisture-induced damage (retained Marshall stability and tensile strength ratio), indirect tensile stiffness modulus, wheel tracking and indirect tensile fatigue tests. Experiment results suggested that stability, resistance to moisture-induced damage and permanent deformation, stiffness, tensile strength and fatigue life of mixtures increased as hydrated lime and bitumen additives were used in mixtures. Hydrated lime usage as filler was identified not to be as effective as usage of SBS, IG and AG as bitumen additive. SBS additive was found to be the most effective in terms of resistance to moisture-induced damage. American Gilsonite was confirmed to be the most effective additive in terms of stability, stiffness, tensile strength and fatigue.