|
|
|
Cements and concentrated model suspensions. Flow, jamming and flocculation.
|
Lootens, Didier (2004) Cements and concentrated model suspensions. Flow, jamming and flocculation. PhD thesis Physique et Chimie des Matériaux, ESPCI. AbstractHere we report about the rheological behavior of very concentrated dispersions -or pastes- of granular or colloidal particles of cement or of monodisperse spherical silica particles. The model system of silica particles is used in order to control the physical chemistry properties of the suspension. Our research project is centered on two points which are focusing on the slurries properties: (i) the first one is the study of the structuring process by the coagulation at rest and its relation with setting. We use special tools (ultrasonic, confocal) to follow and understand the evolution from coagulation to the setting of cement (ii) the second is the study of the dynamic structuring phenomena, under shear, typical of the concentrated suspensions and named jamming. The flow can enter into a shear-thickening and, possibly jamming regime. The onset of this regime is shown to involve giant fluctuations of stress, assigned to the formation and breakup of direct frictional contact chains. The surface state of the particles is a determining factor in this transition. The studies of the normal stress and microscopic observation give good reasons to believe that solid friction is involved in the jamming transition.
| Item Type: | PhD Thesis (PhD) |
|---|
| Thesis Supervisor: | Van Damme, Henri |
|---|
| Date: | October 2004 |
|---|
| Board of examiners: | Joanny, Jean Francois and Moan, Michel and Botet, Robert and Flatt, Robert and Morris, Jeff and Hébraud, Pascal |
|---|
| Ecole Doctorale: | ED 397 PHYSIQUE ET CHIMIE DES MATERIAUX |
|---|
| Discipline: | Physique et Chimie des Matériaux |
|---|
| Collection (Fonds): | ESPCI |
|---|
| Institution: | ESPCI |
|---|
| Subjects: | 3. Physics, Optics |
|---|
| Uncontrolled Keywords: | Cement, Coagulation, Concentrated suspension, Confocal microscopy, Fluctuation, Friction, Jamming, Model system, Normal stress, Rheology, Shear thickening, Shear thinning, Surface state, Ultrasound propagation, Polymer., Ciment, Coagulation, Contrainte normale, Encombrement, état de surface, Fluctuation, Friction, Microscopie confocale, Polymère, Propagation ultrasonore, Rhéoépaississement, Rhéofluidification, Rhéologie, Suspension concentrée, Système modèle. |
|---|
Statistiques de consultation Repository Staff Only: edit this item |
