Use of thixotropy model to capture competition between paste deflocculation and sand particle migration

Author(s): Ye Qian and Shiho Kawashima
Paper category: Proceedings of the International RILEM Conference Materials, Systems and Structures in Civil Engineering 2016 Segment on Fresh Concrete
Editor(s): Lars N. Thrane, Claus Pade, Oldrich Svec and Nicolas Roussel
ISBN: 978-2-35158-184-1
e-ISBN: 978-2-35158-185-8
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 186-195
Total Pages: 10
Language : English

Abstract: Shear-induced particle migration is widely recognized to be a challenge in characterizing the shear rheological properties of fresh cement-based mortar systems. In this study, we aim to quantify particle migration by describing torque decay during steady-state flow with the aid of a thixotropy/migration model. It is found that a two exponential model is needed to sufficiently fit the decay curve of fresh mortars. Physically, we argue that each exponent captures the colloidal deflocculation of the paste phase and shear-induced migration of the granular phase (i.e. sand particles). We explore the competition between these two mechanisms by varying sand volume and clay addition. Results provide support that colloidal deflocculation and shear migration are represented by each of the two exponentials.

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00

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