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FACTEURS DETERMINANT L'ORGANISATION ET LA RHEOLOGIE DU SYSTEME ARGILE-EAU POUR DES SUSPENSIONS DE SMECTITES.

Abstract : Smectites are swelling clays widely used in industry. Theirs mechanical properties are unequal according to their mineralogical and physicochemical characteristics. The aim of this study is to improve the knowledge of the interlayer cation impact on the structure built by the smectite-water system according to the concentration. Homo-ionic (Na+, Ca2+) and bi-ionic systems are observed. This study crosschecks mineralogical methods, physicochemical analysis and broad range of rheometric tests.
At low concentration (less than 60 g/l) the calcium dispersions are shear thinning and few viscous due to the layer association in huge deformable flocks. The sodium smectite layers are dispersed; the dispersions are highly viscous. The lowest viscosity is detected for mix of 20 % of sodium smectite and 80 % of calcium smectite.
At higher concentration (60 to 100 g/l), the yield stress and viscoelastic properties are studied by creep-recovery tests, oscillatory tests and imposed shear step. At the liquid state, the flow is first heterogeneous with a shear banding effect then homogeneous. The results make it possible to define the concentration area characteristic of each mechanical behavior (viscosity, shear thinning and yield stress) according to the saturation cation. The thixotropic properties are characterized with destructuring-restructuring tests. Two kinetics are determined.
Finally we realize a data base with 12 natural and industrial bentonites. The rheograms would be efficient to differentiate the natural calcium bentonites (newtonian law), natural sodium bentonites (Herschel-Bulkley law) and activated calcium bentonites (Bingham law).
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https://tel.archives-ouvertes.fr/tel-00263559
Contributor : Sandrine Paumier <>
Submitted on : Wednesday, March 12, 2008 - 2:25:18 PM
Last modification on : Tuesday, October 22, 2019 - 10:14:04 AM
Long-term archiving on: : Friday, September 28, 2012 - 11:05:11 AM

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  • HAL Id : tel-00263559, version 1

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Sandrine Paumier. FACTEURS DETERMINANT L'ORGANISATION ET LA RHEOLOGIE DU SYSTEME ARGILE-EAU POUR DES SUSPENSIONS DE SMECTITES.. Géologie appliquée. Ecole Supérieure d'Ingénieurs de Poitiers, 2007. Français. ⟨tel-00263559v1⟩

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