Novel Tri-Viscous-Model to Simulate Pumping of Flowable Concrete Through Characterization of Lubrication-Layer and Plug-Zones (2021-12)¶

In this study, computational fluid dynamics (CFD) was employed to simulate the pipe flow of 18 self-consolidating and four highly-workable concrete mixtures in a 30-m long pumping circuit. Pressure loss (ΔP) in 100- and 125-mm diameter (DP) pipelines was measured under low (1.2–6.2 l/s) and high (8.1–16.4 l/s) flow rates (Q). The numerical simulation was successfully carried out using a two-fluid model and a new variable-viscosity single-fluid approach, namely double-Bingham and tri-viscous models, respectively. The radial variation of rheological properties of the concrete across the pipe section, representing the plug flow, sheared concrete, and lubrication layer (LL) zones was successfully simulated based on a total of 404 pipe flow experiments. The relative LL viscous constant (ηLL) values obtained using numerical simulations-to-those obtained experimentally using a tribometer ranged between 30% and 200%. Moreover, the coupled effect of the characteristics of different flow zones, DP, and Q on ΔP was evaluated.