Results 181 to 190 of about 15,071 (234)
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Synthetic Preparation of Ettringite
Advanced Materials Research, 2014This work is the opening chapter of the study that deals with products of degradation, which might form in hardened cement paste after exposure to sulphate attack.
Marcela Fridrichová +4 more
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Investigations on ettringite cements
Advances in Cement Research, 1994Cement pastes were prepared by mixing C3A, CA, C4A3S, C4AF or a CaO-Al2O3-SiO2 glass as Al3+ donor with CaSO4·2H2O, Ca(OH) and water. After curing in completely closed moulds to prevent expansion, the hardened pastes exhibited strength properties comparable with those of other inorganic cements.
I Odler, P. Yan
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Expansive admixtures (mainly ettringite)
Cement and Concrete Composites, 1998Abstract The hydration chemistry of expansive cements is described with emphasis on the components for formation of ettringites. Expansive cement concrete as ‘shrinkage-compensating concrete’ or ‘chemical prestressing concrete’ is applied to many kinds of concrete construction.
S. Nagataki, H. Gomi
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Cement and Concrete Research, 1993
Abstract Solid solutions of ettringites containing SO42−, B(OH)4− and CrO42− were investigated. The compositions of the solid solutions under different synthesis conditions are represented by paste reaction (1) and “saccharate method” (2): 1. 1: [Ca6Al2 (OH)12·24H2O]6+ [(3−3x) (SO4)·(3x) (Cro4)·2H2O]6− 0≤x≤1 2. 2: [Ca6Al2 (OH)12·24H2O]6+ [(x)
H. Poellmann +3 more
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Abstract Solid solutions of ettringites containing SO42−, B(OH)4− and CrO42− were investigated. The compositions of the solid solutions under different synthesis conditions are represented by paste reaction (1) and “saccharate method” (2): 1. 1: [Ca6Al2 (OH)12·24H2O]6+ [(3−3x) (SO4)·(3x) (Cro4)·2H2O]6− 0≤x≤1 2. 2: [Ca6Al2 (OH)12·24H2O]6+ [(x)
H. Poellmann +3 more
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Crystal chemistry of ettringite
Mineralogical Magazine and Journal of the Mineralogical Society, 1962Summary Crystal-chemical calculations are based on three chemically analysed samples of ettringite and their respective unit-cell dimensions and specific gravities. The large hexagonal unit cell is deduced to contain 384 oxygen atoms, 64 cations with co-ordination number 6 or more, and 48 cations with co-ordination number 4 or less.
Duncan McConnell, Joseph Murdoch
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C4A3 hydration ettringite formation, and its expansion mechanism: I. expansion; Ettringite stability
Cement and Concrete Research, 1981Abstract C 4 A 3 S hydration, the mechanism of C 4 A 3 S expansion, ettringite formation and its thermal stability are examined in a 3-part study. In this part, the amount of ettringite formed and the C 4 A 3 S degree of hydration are interrelated, and correlated with the degree of expansion beyond an induction period for the ...
K. Ogawa, D.M. Roy
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Advances in Cement Research, 1993
Ettringite was formed during the hydration of C3A with gypsum at temperatures between 25 and 80°C. Ettringite formation was retarded when hydration was carried out in KOH solutions whose concentrations were as high as 2·0M. Solutions with KOH concentrations between 0·5 and 1 . OM have the greatest retarding effect.
P. W. Brown, J. V. Bothe
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Ettringite was formed during the hydration of C3A with gypsum at temperatures between 25 and 80°C. Ettringite formation was retarded when hydration was carried out in KOH solutions whose concentrations were as high as 2·0M. Solutions with KOH concentrations between 0·5 and 1 . OM have the greatest retarding effect.
P. W. Brown, J. V. Bothe
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Ettringite Deposits in Air Voids
Transportation Research Record: Journal of the Transportation Research Board, 2004Investigations of pavements suffering from freeze-thaw damage in the presence of deicing salts have found significant deposits of ettringite in the air voids. Concern has been expressed that the deposition of ettringite in air voids reduces their effectiveness in protecting the concrete.
Rachel J. Detwiler +2 more
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The kinetics of ettringite formation
Cement and Concrete Research, 1989Abstract Conversion of hemihydrate to gypsum, and ettringite formation in the system C 3 A CaSO 4 · 1 2 H 2 O H 2 O three hydration temperatures using x-ray diffraction. Analysis of the kinetics of gypsum formation suggests that the rate limiting step changes from an initial dependence on the hemihydrate ...
Paul Wencil Brown, Phillip LaCroix
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In-situ observation of ettringite crystals
Journal of Crystal Growth, 2009In-situ observation of growing ettringite crystals in solution has been carried out and the morphology change of ettringite has been investigated under various conditions. In particular, the acceleration behavior of ettringite growth in the presence of calcite, the cause of which is not yet understood, is examined.
Ryuichi Komatsu +3 more
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