A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Formation of calcium sulfoaluminate hydrate compounds. Part II
The formation of ettringite (3CaO dot Al2O3 dot CaSO4 dot 32H2O) and monosulfate (3CaO dot Al2O3 dot CaSO4 dot 12H2O) from tricalcium aluminate (3CaO dot Al2O3), gypsum (CaSO4 dot 2H2O), and sodium hydroxide (NaOH) solutions were investigated by isothermal calorimetry and X-ray diffraction analyses. Tricalcium aluminate/gypsum mixtures with a molar ratio of 1:1 sulfate-to-aluminate were hydrated at constant temperatures from 30 to 90 degree C in deionized water and in 200 and 500 mM of sodium hydroxide (NaOH) solutions. Hydration in deionized water produced ettringite and monosulfate as the dominant crystalline phases, regardless of temperature. Complex assemblages of phases formed in 200 and 500 mM of sodium hydroxide; these included ettringite, monosulfate, and U-phase, at all temperatures. Calorimetry and X-ray diffraction data indicated that U-phase formation becomes the dominant reaction as sodium hydroxide concentrations increase. U-phase is the only AFm phase observed after hydration in 1.0 M of NaOH. The data also indicated that the presence of sodium cations promotes AFm formation.
Formation of calcium sulfoaluminate hydrate compounds. Part II
The formation of ettringite (3CaO dot Al2O3 dot CaSO4 dot 32H2O) and monosulfate (3CaO dot Al2O3 dot CaSO4 dot 12H2O) from tricalcium aluminate (3CaO dot Al2O3), gypsum (CaSO4 dot 2H2O), and sodium hydroxide (NaOH) solutions were investigated by isothermal calorimetry and X-ray diffraction analyses. Tricalcium aluminate/gypsum mixtures with a molar ratio of 1:1 sulfate-to-aluminate were hydrated at constant temperatures from 30 to 90 degree C in deionized water and in 200 and 500 mM of sodium hydroxide (NaOH) solutions. Hydration in deionized water produced ettringite and monosulfate as the dominant crystalline phases, regardless of temperature. Complex assemblages of phases formed in 200 and 500 mM of sodium hydroxide; these included ettringite, monosulfate, and U-phase, at all temperatures. Calorimetry and X-ray diffraction data indicated that U-phase formation becomes the dominant reaction as sodium hydroxide concentrations increase. U-phase is the only AFm phase observed after hydration in 1.0 M of NaOH. The data also indicated that the presence of sodium cations promotes AFm formation.
Formation of calcium sulfoaluminate hydrate compounds. Part II
Clark, B.A. (author) / Brown, P.W. (author)
Cement and Concrete Research ; 30 ; 233-240
2000
8 Seiten, 27 Quellen
Article (Journal)
English
Formation of calcium sulfoaluminate hydrate compounds: Part I
| Tema Archive | 1999
The formation of calcium sulfoaluminate hydrate compounds
| Online Contents | 2000
The formation of calcium sulfoaluminate hydrate compounds
| British Library Online Contents | 2000
The formation of calcium sulfoaluminate hydrate compounds
| Online Contents | 1999
| British Library Online Contents | 1999