Nanocellulose-stabilized bitumen emulsions as a base for preparation of nanocomposite asphalt binders

Pickering bitumen emulsions stabilized by 1 % aqueous dispersion of microfibrillated cellulose (MFC) were used to obtain micro- and nanocomposite asphalt binders. Initial bitumen emulsions are characterized by a yield stress for a bitumen content of up to 40 %, while higher bitumen amounts result in phase inversion with the formation of highly viscous inverse emulsions. Drying of emulsions leads to the production of nanocomposite bitumen binders containing from 0.6 % to 8.3 % of MFC. In this case, the MFC content of 1.5 % or more formed a microfibrillar network in the bitumen, which gives it gel-like properties and the yield stress, increasing its cohesive strength and resistance to rutting. The effect of addition of 5 % sodium dodecyl sulfate (SDS) on the properties of the bitumen emulsions and the resulting binders is considered. SDS increases the emulsifying ability of MFC, making it possible to obtain 70 % direct bitumen emulsions and reducing their effective viscosity together with the yield stress. However, the presence of SDS in the dried binders increases the aggregation of MFC, reducing the stiffness of the resulting microcomposite binders, their yield stress, and rutting resistance.