Volume 15, No. 1, 2021
Received: 2021/01/09, Accepted:
Authors:
Omar Taleb; Fouad Ghomari; Mohammed Amine Boukli Hacene; Mustapha Henaoui; Hamza Soualhi;
Abstract:
Vane rheometers are widely used in determining the rheological properties of concrete. However, the geometry of the vane can have an impact on stress calculation. This research falls within this context. Indeed, an experimental study, using a rheometer with an inverted double U-shaped vane, was carried out to study the rheological behavior of self-compacting concrete (SCC) with different granular skeletons. The accuracy of the results was then discussed with respect to the distributions of pressures, stresses and shear rates within the gap, by conducting Computational Fluid Dynamics (CFD) simulations.
The experimental results obtained showed that SCC has a nonlinear behavior which can be described by the Herschel-Bulkley model. In addition, a ratio (gravel/ sand) close to 1 could ensure a low shear threshold and a sufficient viscosity to avoid segregation. In addition, numerical simulations showed that the shape of the blade
used can generate depression areas which can affect the global stress value. Moreover, it was found more interesting to round the bottom corners of the blades in order to reduce the risk of segregation. Numerical analysis also revealed that the rheometer used can also provide suitable shear rates for concrete mixing or pumping studies.
Keywords:
Self-compacting concrete, Rheology, Vane rheometer; Computational fluid dynamics, Yield stress, Viscosity