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The mechanisms behind shear thickening behaviour of fresh self-compacting concrete

Author(s): D. Feys, R. Verhoeven, G. De Schutter
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: 105 - 112
Total Pages: 8
Language: English

Shear thickening in fresh self-compacting concrete is a phenomenon which has been described only a few times in literature. However, it is a phenomenon that should not be neglected, as it increases the viscosity of the material at high shear rates. Breaking of concrete mixers and excessive pumping pressures, with a possible rupture of the piping system, can be the vry dangerous consequences of not taking into account shear thickening.
From the rheology literature, it is known that shear thickening can have different causes. The two most applied theories are the formation of temporary clusters of fine particles and the transfer of momentum between larger particles.
Experiments with more than 60 different SCC mixes have revealed, after elimination of measurement artefacts, that there is a certain critical shear stress above which shear thickening occurs. Other evolutions in the obtained results, like the increase in shear thickening with increasing SP dosage and the fact that traditional cement paste/concrete does not show shear thickening for the same shear rates, tend in favour of the cluster-formation theory. Although, these conclusions cannot be generalised and momentum transfer cannot be excluded anytime.

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

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