Viscoelastic Response of Bitumen Emulsion Mastic with Various Active Fillers

The performance of the Cold Bitumen Emulsion (CBE) mixture is strongly controlled by the bituminous binder (bitumen emulsion) and the hydraulic binder (active filler). CBE mixture behavior, based on the mastic (both earlier mentioned binders) properties, may vary from a stiff behavior (hydraulic binder) to an asphalt like behavior with viscoelastic deformation failure (bitumen emulsion). This research aims to assess the impact of different fillers on the viscoelastic characteristics of CBE materials and also to evaluate the suitability of the sigmoid model to describe the rheological properties of CBE mastic. To address this aim, bitumen emulsion was mixed separately with eight fillers/blended fillers. The rheological properties of the prepared mastics were evaluated by conducting oscillating temperature-frequency sweep tests, utilizing the Dynamic Shear Rheometer (DSR). The raw data were shifted to the reference temperature and modelled using the sigmoid model to get a smooth master curve. Results showed that most of the active fillers exhibited stiff behaviour. Among the eight fillers, two of them own balanced rheological characteristics while only two fillers reduced the neat CBE binder complex modules. It was found that the sigmoid model was able to satisfactorily describe the rheological properties of CBE binder and mastic over a range of temperatures and frequencies.