Computational Investigation of Concrete Pipe Flow: Critical Review

The prediction of concrete pumpability is of particular interest to properly design pumping circuits and select suitable pumps for successful processing of concrete. A critical review of empirical, analytical, and numerical models is carried out to predict concrete pumpability as a function of pipeline geometry, rheological properties of the bulk concrete, and the characteristics of the lubrication layer. The main mechanisms leading to the formation of the lubrication layer, including the wall effect, Reynolds dilatancy, and shear-induced particle migration (SIPM), are discussed. The main phenomenological models governing SIPM are formulated in terms of spatial variations of particles' interaction frequency and viscosity. In addition to the single-phase methodology, new computational approaches on SIPM in pipe flow of solid-liquid suspensions are discussed. The coupled computational fluid dynamics-discrete element method (CFD-DEM) and smoothed-particle hydrodynamics (SPH) methods are recommended as the most precise and realistic approaches to simulate concrete pipe flow compared to the DEM and single-phase modelings.