6533b86efe1ef96bd12cc8c9
RESEARCH PRODUCT
Experimental study of Si–Al substitution in calcium-silicate-hydrate (C-S-H) prepared under equilibrium conditions.
André NonatIsabelle PochardXiaolin Pardalsubject
Calcium hydroxideCalcium-silicate-hydrate (C-S-H)Aluminium hydroxide0211 other engineering and technologiesAnalytical chemistryMineralogychemistry.chemical_elementIonic bonding02 engineering and technologyBuilding and ConstructionCalcium021001 nanoscience & nanotechnologyKinetic energychemistry.chemical_compoundChemistrychemistryAluminium021105 building & constructionAluminiumThermodynamic equilibriaGeneral Materials ScienceTricalcium aluminateCalcium silicate hydrate0210 nano-technologydescription
International audience; C-A-S-H of varying Al/Si and Ca/(Al+Si) ratios have been prepared introducing C-S-H (Ca/Si=0.66 and 0.95) at different weight concentrations in a solution coming from the hydration of tricalcium aluminate (Ca3Al2O6) in water. XRD and EDX (TEM) analyses show that using this typical synthesise procedure, pure C-A-S-H is obtained only for calcium hydroxide concentrations below 4.5 mmol L−1. Otherwise, calcium carboaluminate or strätlingite is also present beside C-A-S-H. The tobermorite-like structure is maintained for C-A-S-H. A kinetic study has shown that the formation of C-A-S-H is a fast reaction, typically less than a few hours. The Ca/(Al+Si) ratio of C-A-S-H matches the Ca/Si ratio of the initial C-S-H, in the ionic concentration range studied i.e., less than 4.5 and 3 mmol L−1 of calcium hydroxide and aluminium hydroxide respectively. The Al/Si ratio increases with the aluminium concentration in the solution and reaches a maximum value of 0.19.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2009-08-01 |