Search results for "Rhéologie"
showing 8 items of 8 documents
Interactions ciment-organofunctional silanes : implications on hydration and on mechanical properties of the modified systems
2010
Nowadays concrete is the most attractive option for the construction sector. This is because concrete itself is a low cost, low energy and low environmental impact material. Moreover, concrete structures are very durable and high load bearing. This is achieved by incorporating steel, because concrete itself is a very low tensile strength material. Chemically, the weakness originates in the cohesive nature of cement used for concrete making. Nanoscale experimental investigations and numerical simulations showed that cohesion of cement paste is caused by short range surface forces acting between calcium silicate hydrates (C-S-H) in the interstitial solution. This thesis addresses the possibil…
Modelling the cement-latex interactions : experimental and simulation approach : Consequences on the rheological propertiec
2014
Latex is used in industrial mortars to improve the material properties. This behaviour is obviously related to the interactions between cement phases and latex which are still not understood. In this frame, the aim of the present work is to understand the role of latexes in mortar in particular how the various latex characteristics, such as the latex chemistry surface, or the latex size, influence the characteristics of this complex granular system. The major issue concerns the reactivity of the cement: indeed, several parameters are modified during cement hydration which governs the development of the paste mechanical properties. Consequently in order to avoid side effects due to cement hy…
Influence of superplasticizers structure on the hydration, the initial surface creation and the fluidity of cement model systems
2014
Nowadays the use of superplasticizers admixtures becomes unavoidable for concrete. It allows enhancing the rheological properties at the fresh state: the initial flow and slump retention during the 2-3 first hours of the life of a concrete. The understanding of this mechanism is still partly elucidated for PCE (grafted copolymers). The aim of this thesis was to challenge the assumption of the evolution of the adsorbed amount of PCE per instantaneous mineral surface unit as origin of the fluidity temporal evolution during the workability period.On an inert system (calcite), we confirmed that the fluidity is mainly governed by the adsorption level. Thus for a same surface adsorption density, …
On the study of the different factors influencing the structure and the texture of semi-humid baked aerated cereal products : sensory and instrumenta…
2014
Since texture is the manifestation of structural, mechanical and surface properties of a material, it represents a key characteristic for food materials. It reflects food quality, freshness perception influencing consumer acceptance.Studies encountered in the scientific literature that are devoted to cereal based foods texture are foremost based on bread also biscuits scarcely on cakes. This study entitled ‘study of the different factors influencing the structure and the texture of semi-humid baked aerated cereal products: sensory and instrumental dimensions of texture’ focus on cake softness characterization, set up and evolution. First, the investigation of the influence of soft wheat flo…
Study of the action of phosphate ions contained in the mixing water of the hydration of a Portland cement.
2005
Cementation is considered as the most attractive solution for the conditioning of low and intermediate radioactive wastes. The species contained in these wastes can strongly influence the reactivity of the cement pastes, it is in particular the case of the ortho-phosphate ions which are found in the evaporation concentrates. The aim of our work was to determine the influence of these ions on the hydration and the rheological properties of the cement pastes at early age as well as the mechanical and physical properties on the hardened material.
Viscosity of artificial bolus of high protein extruded snacks
2018
Pulse legumes (pea, lentil, faba bean) are excellent source of proteins (20-30% db), dietary fibers (10-30%), and starch (40-55%). The formulation of gluten-free extruded snacks made entirely from pulse legumes is an interesting way to introduce legumes to young people. Due to the reactivity of protein components under thermomechanical treatment, extrusion can produce cellular structures with various texture and starch-protein composite morphology. In turn, the morphology of parietal material governs masticatory performances. For the first time, the interaction coefficient between bolus and saliva was determined by taking into account multi-scale structure of high-protein solid foams. The p…
Influence de l'état protéique sur la dynamique de séparation de phase et de gélification dans un système ternaire aqueux à base de protéines de pois …
2012
Two aqueous systems at 20°C in 0.1 M NaCl and pH 7.2 containing globular pea proteins and sodium alginate were investigated in this study. First, phase behavior of (i) either low-denatured mixed globulins or (ii) their thermally pre-aggregated counterparts - alginate mixtures was compared using a multi-scale approach, by means of phase diagram and microstructure analysis by confocal microscopy. Thermodynamic incompatibility was the main driving force leading to phase separation within the mixtures, which presented according to their initial biopolymer composition both different morphological and time-evolution features of coexisting phases. Thereafter, a cold-set gelation for each system wa…
Rhéologie et déformation du verre dans des conditions extrêmes
2018
Hardness measurements performed at room temperature have proven that glass can flow under elevated pressure. During industrial glass production processes, the actual distribution of stress components in the glass during scribing remains, to date, poorly quantified, and thus continues to be challenging to model numerically. To better quantify the viscous contribution to the rheology of glass, the effect of pressure on the viscosity and structural relaxation of glass, needs to be quantified experimentally by in situ deformation measurements.In this thesis, I performed experiments and models to study: (i) the volumetric relaxation of glass after high-pressure treatment above the glass transiti…