Effect of type of aggregate on permanent deformation of bituminous concrete mixes

The physical properties and performance of hot mix asphalt are governed by the properties of the aggregate, properties of the asphalt binder and asphalt–aggregate interactions. The study is aimed to compare the behaviour of bitumen containing various type of modifiers [styrene-butadiene-styrene (SBS) and ethylene-vinyl-acetate (EVA)] and aggregates (acidic and basic characters) for preparing hot mix asphalt on permanent deformation. Rutting and static creep tests were performed on various mixes to evaluate permanent deformation. Dynamic shear rheometer was used to determine the rheological properties and hence rutting parameter (G*/Sinδ). The results indicate that polymer modification increased rutting resistance. Moreover, samples prepared with EVA are more resistant to deformation compared to those prepared with SBS. Mixes consisting of quartzite aggregate are likely to deform more compared to marble mixes, both for modified and unmodified bituminous mixes, but the recovery of quartzite mixes on removal of load is also more.