Skip to Main content Skip to Navigation
Theses

Influence des hydroxypropylguars sur les propriétés des mortiers de ciment à l’état frais

Abstract : Modern factory-made mortars are complex materials, in which are added some kinds of admixtures used to exhibit various properties. Polysaccharides are admixtures used in order to improve water retention capacity and rheological behavior of freshly-mixed mortars.However, polysaccharides induce a delay of cement hydration and represent a large part of mortar raw material cost. The improvement of the knowledge about polysaccharide-cement interaction is therefore necessary. In past, different behaviors were observed according to the kind of polysaccharide. The study of a new polysaccharide family is thus a major way of research. The hydroxypropylguars were chosen since they were presented as promising water retention agents and they are now well-established in the construction industry.Results show that HPG improve the water retention capacity of cement-based mortars. The working mechanism is attributed to the formation of HPG aggregates above a critical dosage, which may stop the water flow by plugging the porous network at the interface mortar-substrate. Moreover, HPG induce a decrease in the hydrates growth rate because of adsorption on the cement hydrated phases, and enhance the consistency and the yield stress of mortars. All these properties are influenced by the pre-dissolution of HPG in the mixing water. A methodology of ultrasonic degradation was also established in order to study the molecular weight influence of polysaccharides on fresh-state properties. Cellulose ethers were systematically investigated as polysaccharidic admixture reference.
Document type :
Theses
Complete list of metadatas

Cited literature [265 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00936958
Contributor : Abes Star :  Contact
Submitted on : Monday, January 27, 2014 - 4:12:10 PM
Last modification on : Wednesday, June 24, 2020 - 4:19:08 PM
Long-term archiving on: : Sunday, April 27, 2014 - 10:56:47 PM

File

poinot-thomas-diff.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-00936958, version 1

Citation

Thomas Poinot. Influence des hydroxypropylguars sur les propriétés des mortiers de ciment à l’état frais. Autre. Ecole Nationale Supérieure des Mines de Saint-Etienne, 2013. Français. ⟨NNT : 2013EMSE0720⟩. ⟨tel-00936958⟩

Share

Metrics

Record views

755

Files downloads

4472