44. Influence of microfillers on the rheological behaviour of cement pastes: comparison between silica fume and micronized quartz

Title: 44. Influence of microfillers on the rheological behaviour of cement pastes: comparison between silica fume and micronized quartz
Author(s): A. Vasylchenko, M. Chaouche, M. Moranville, P. Naproux
Paper category : conference
Book title: 5th International RILEM Symposium on Self-Compacting Concrete
Editor(s): G. De Schutter and V. Boel
Print-ISBN: 978-2-35158-047-9
e-ISBN: 978-2-35158-088-2
Publisher: RILEM Publications SARL
Publication year: 2007
Pages: 303 - 308
Total Pages: 6
Nb references: 3
Language: English

Abstract: The steady state rheological properties of cement pastes were investigated as a function of the mix-design constituents. In particular a comparison between the performances of two types of microfillers has been performed. Namely silica fumes (both condensed (CSF) and uncondensed (USF)) and micronized quartz (MQ) with two different finenesses. The influence of the type and dosage of the high water reducer admixture (HWRA) was also investigated. The pastes were found to behave as Herschel-Bulkley fluids. However, the rheological parameters, including the yield stress, the consistency and the fluidity index, were in general dependent upon the shear-rate interval considered. The pastes mix-designed with silica fume were found to be shear-thinning at small shear rates and shear-thickening at high shear rates, while those with MQ were shear-thickening throughout the whole shear-rate interval considered. The pastes with MQ and USF had comparable yield stresses, in agreement with spread tests performed on mortars. At high shear rates the difference between the rheological behaviours of the MQ and SF pastes was found to be highly sensitive to the type of HWRA.

Online publication: 2009-06-16
Publication type : full_text
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