0000000000162764

AUTHOR

Laure Regnaud

showing 3 related works from this author

Mechanisms and parameters controlling the tricalcium aluminate reactivity in the presence of gypsum.

2007

International audience; To understand the mechanisms and the parameters controlling the reactivity of tricalcium aluminate in the presence of gypsum at an early age, a study of the hydration of the “C3A–sulphate” system by isothermal microcalorimetry, conductimetry and a monitoring of the ionic concentrations of diluted system suspensions have been carried out with various gypsum quantities. The role of C3A source and its fineness were also studied. This work shows the fast initial formation of AFm phase followed by ettringite formation during the period when the sulphate is consumed. It has been highlighted that the time necessary to consume all the gypsum varies with the type of C3A and i…

Isothermal microcalorimetryEttringiteGypsumFineness0211 other engineering and technologieschemistry.chemical_elementMineralogyHydrationchemical and pharmacologic phenomena02 engineering and technologyCalciumengineering.materialEttringitechemistry.chemical_compound021105 building & constructionGeneral Materials ScienceReactivity (chemistry)Tricalcium aluminateBuilding and ConstructionCa3Al2O6021001 nanoscience & nanotechnologyKineticschemistryChemical engineeringengineering0210 nano-technologyAFm phase
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Early C3A hydration in the presence of different kinds of calcium sulfate.

2009

International audience; Hydration reactions of C3A with various amounts of calcium sulfate hemihydrate, gypsum or a mixture of two, were investigated by isothermal microcalorimetry, and a monitoring of the ionic concentrations of diluted suspensions. This study shows that sulfate type used modifies the early C3A-CaSO4 hydration products and the rate of this hydration. The fast initial AFm formation observed before ettringite precipitation in the C3A-gypsum system is avoided as soon as hemihydrate is present in the suspension. This was attributed to.higher super saturation degrees and then higher nucleation frequency with regard to the ettringite obtained in the presence of hemihydrate. More…

Isothermal microcalorimetryEttringiteGypsumInorganic chemistry0211 other engineering and technologiesNucleationHydrationchemical and pharmacologic phenomena02 engineering and technologyengineering.materialEttringitechemistry.chemical_compound021105 building & constructionGeneral Materials ScienceTricalcium aluminateSulfateSupersaturationPrecipitation (chemistry)Chemistry[CHIM.MATE]Chemical Sciences/Material chemistryBuilding and ConstructionCa3Al2O6021001 nanoscience & nanotechnologyKinetics[ CHIM.MATE ] Chemical Sciences/Material chemistryengineering0210 nano-technology
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Changes in Cement Paste and Mortar Fluidity after mixing induced by PCP: A parametric study

2006

International audience; The interaction mechanism between polycarboxylate-type superplasticizer (PCP) and cement hydration is not fully understood and incompatibilities between concrete and additive are sometimes observed. In some cases, the fluidity tends to increase (“overfluidification”) few minutes after mixing. This is a problem because the overfluidification leds to bleeding of the concrete which could be critical on job site. Our study consisted first in highlighting the phenomenon of “over-fluidification” by slump flow tests on mortar. Next, the time evolution of the rheological behaviour of cement pastes in the presence of PCP was analysed thanks to a rheometry protocol in order to…

Cement[CHIM.MATE] Chemical Sciences/Material chemistryMaterials scienceslump flowRheometrySuperplasticizerMixing (process engineering)[CHIM.MATE]Chemical Sciences/Material chemistryfluidityCivil engineeringsulphatePCPAdsorption“over-fluidification”Rheologyadsorption[ CHIM.MATE ] Chemical Sciences/Material chemistryComposite materialMortarParametric statistics
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