INVESTIGATION INTO A FLOW OF A POLYMER–BITUMEN BINDER, DESCRIBED BY THE CROSS MODEL, IN A CYLINDRICAL PIPE

Mathematical modeling of a fl ow of polymer–bitumen binder in a cylindrical pipe has been carried out. Oxidized BND 70/100 grade butadiene–styrene copolymer-modifi ed bitumens have been selected for investigations. The results of investigations have shown that the rheological properties of the binding substances under consideration can be described with the Cross model. At low shear rates, the spatial structure formed as a result of modifying bitumen with a polymer remains unchanged, and the fl ow is characterized by high eff ective viscosity values. At high shear rates, the process of spatial structure breakdown becomes intense and is accompanied by viscosity decrease. With increase in temperature the binder passes from a gel state to a liquid state. With increase in the average fl ow rate the formation of a dynamic boundary layer and the fl ow stabilization occur at large distances from the inlet. The eff ective viscosity values in the near-axial zone increase downstream. With hydrodynamic stabilization in the nearaxial region a high-viscosity fl ow zone is formed. In the pre-axial fl ow zone, the eff ective viscosity assumes maximum values, while near the wall, it takes minimum values.
Mathematical modeling of a fl ow of polymer–bitumen binder in a cylindrical pipe has been carried out. Oxidized BND 70/100 grade butadiene–styrene copolymer-modifi ed bitumens have been selected for investigations. The results of investigations have shown that the rheological properties of the binding substances under consideration can be described with the Cross model. At low shear rates, the spatial structure formed as a result of modifying bitumen with a polymer remains unchanged, and the fl ow is characterized by high eff ective viscosity values. At high shear rates, the process of spatial structure breakdown becomes intense and is accompanied by viscosity decrease. With increase in temperature the binder passes from a gel state to a liquid state. With increase in the average fl ow rate the formation of a dynamic boundary layer and the fl ow stabilization occur at large distances from the inlet. The eff ective viscosity values in the near-axial zone increase downstream. With hydrodynamic stabilization in the nearaxial region a high-viscosity fl ow zone is formed. In the pre-axial fl ow zone, the eff ective viscosity assumes maximum values, while near the wall, it takes minimum values.
Author:  O. V. Matvienko, N. S. Firsanova, O. A. Skvortsova, and I. S. Cherkasov
Keywords:  rheology, road construction, bitumen binders, SBS-polymer, viscosity, non-Newtonian liquid, Cross model.
Page:  479