Results 131 to 140 of about 3,590 (187)
Some of the next articles are maybe not open access.
Applied Mechanics and Materials, 2015
The exposure of cement to high concentration of sulphate anions for a prolonged time period can lead to the formation of secondary ettringite and thaumasite. The preparation of synthetic ettringite is described in this paper.
Jan Gemrich +3 more
openaire +1 more source
The exposure of cement to high concentration of sulphate anions for a prolonged time period can lead to the formation of secondary ettringite and thaumasite. The preparation of synthetic ettringite is described in this paper.
Jan Gemrich +3 more
openaire +1 more source
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
openaire +1 more source
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
openaire +1 more source
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
openaire +1 more source
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
openaire +1 more source
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
openaire +1 more source
Borate Substituted Ettringites
MRS Proceedings, 1992ABSTRACTThe setting of cement is adversely affected by soluble borates. To reduce interference, the extent to which borate can be insolubilized has been investigated. One specific mechanism of insolubilization is by inclusion into ettringite. Ettringite, Ca6Al2(SO4)3(OH)12·26H2O, is a normal and stable constituent of Portland cement. It has an open but
Csetenyi, Laszlo J., Glasser, F. P.
openaire +2 more sources
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
openaire +1 more source
Minerals explained 59: Ettringite
Geology Today, 2021Some minerals are of interest both in fundamental and applied sciences. This is especially the case for ettringite Ca6Al2(SO4)3(OH)12·26H2O (hexagonal). As a secondary mineral, it was described in 1874 in limestone xenoliths from the Eifel volcanic area in Germany.
Thiéry, Vincent, Rica, Brunilda
openaire +3 more sources
Natural specimen of triple solid solution ettringite–thaumasite–chromate-ettringite
Journal of Thermal Analysis and Calorimetry, 2013Three natural minerals of ettringite group were investigated by TG to refine their chemical composition. Two samples are ettringite Ca5.97Mg0.01Sr0.02Al1.99Cr0.01(SO4)3(OH)12·23.7H2O and bentorite Ca5.99Mg0.01Cr1.95Al0.01Si0.03(SO4)2.82·(CO3)0.20(OH)12·19.4H2O, but the third one Ca5.99Na0.01Al1.38Si0.62(SO4)2.49·(CrO4)0.36·(CO3)0.46(OH)12·15.8H2O has ...
V. A. Drebushchak +3 more
openaire +1 more source
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
openaire +1 more source
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
openaire +1 more source