Perturbation patterns and velocity modelling of a fresh concrete around a spherical probe viscoprobeTM immersed in concrete mixers

Author(s): S. Mokéddem, N. Roquet, B. Cazacliu, C. Lanos
Paper category: Symposium
Book title: 3rd International RILEM Symposium on Rheology of Cement Suspensions such as Fresh Concrete
Editor(s): O.H. Wallevik, S. Kubens, S. Oesterheld
ISBN: 978-2-35158-091-2
e-ISBN: 978-2-35158-092-9
Pages: 155 - 162
Total Pages: 8
Language: English

Abstract: 
ViscoprobeTM is a system made of a spherical probe and a software, intended to deduce inline some rheological parameters of a fresh concrete, during the elaboration process. The software analyses a strength signal, assuming the Stokes's law. In the indsutrial practice, the analysis is efficient for sufficient fluid concrete as self compacting concrete [1]. In the present paper, the velocity field induced in two concrete mixers is analysed using numerical simulations, in order to assess the use of the Stokes's law for such complex non-Newtonian flows. The perturbation patterns created by the presence of a probe are analysed, first by exhibiting the influence of the probe on the global flow, then by displaying the influence of the blades on the local flow due to the probe alone. It is shown that, among the hypothesis of the Stokes's law, assuming that the fluid is at rest at infinity appears to be relevant in the studied cases. Also, the analysis reveals that concrete with higher Bingham behaviour requires more complex drag force estimation, including non-Newtonian rheology effect.

Online publication: 2009
Publication Type: full_text
Public price (Euros): 0.00