Rheological Properties of Bituminous Mastic with Different Filler Content

Abstract

Bituminous mixture is widely used for pavement construction. It is made of coarse aggregates, fine aggregates and mineral filler, and mixed with bitumen. The coarse aggregates form a skeleton structure in mixture and the fine gravel with bitumen form a mortar. The mineral filler with bitumen forming a mastic, which determines the rheological characteristics of bituminous mixture. This study focuses on rheological properties of bituminous mastic with different content of mineral filler and with different types of bitumen such as base bitumen, SBS modified bitumen and warm bitumen (modified by Evotherm or Sasobit). By measuring the penetration, ductility and softening point of different mastics, and by applying the Brookfield test and DSR test, the viscosity-temperature curve and viscoelastic property are analyzed. The contribution of mineral filler content in mastic is discussed. The difference of rheological property among different mastic is emphasized, and the effects of warm mixing are analyzed. The results show that the technical parameters of bituminous mastic (penetration, ductility, softening point and viscosity) change linearly with the mineral filler content in normal or semi-logarithmic coordinates. The warm bituminous mastic has a larger phase angle in dynamic viscoelastic analysis and SBS bituminous mastic has a smaller phase angle. The warm additive of type “surfactant” doesn’t change the technical parameters of bitumen, but increases dynamic shear modulus, the warm type of “bitumen viscosity reduction” changes the technical parameters of bitumen.