Thaumasite
Thaumasite is a silicate mineral with chemical formula Ca3Si(OH)6(CO3)(SO4)·12H2O. It occurs as colorless to white prismatic hexagonal crystals, typically as acicular radiating groups. It also occurs as fibrous masses. Its Mohs hardness is 3.5 and it has a specific gravity of 1.88 to 1.90. Optically it is uniaxial negative with indices of refraction of nω = 1.507 and nε = 1.468.
It occurs as a hydrothermal alteration mineral in sulfide ore deposits and geothermal alteration of basalt and tuff. It occurs with zeolites, apophyllite, analcime, calcite, gypsum and pyrite.
Thaumasite can also be formed along with other calcium silicate hydrates (CSH) during cement alteration, especially when sulfate attack develops.
It was first described in 1878 in Sweden and named from the Greek, "thaumazein", to be surprised, in reference to its unusual composition with carbonate, sulfate and hydroxysilicate anions.
The silicate structure of thaumasite is unusual due to the presence of non-tetrahedral silicon in its crystal lattice. Indeed, an atypic octahedral configuration is observed for Si present in thaumasite in the form of hexahydroxysilicate: [Si(OH)6]2−, a species exhibiting a geometry similar to that of the hexafluorosilicate [SiF6]2−.

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Thaumasite - Wikipedia, the free encyclopedia
Thaumasite. Thaumasite w-prehnite Hydrous basic calcium carbonate sulfate and silicate Fairfax Quarry near Contraville Fairfax. Thaumasite (white) with ...
en.wikipedia.org/wiki/Thaumasite
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Thaumasite Mineral Data
Name Pronunciation: Thaumasite + Pronunciation Say Thaumasite ... Click Here for Larger Thaumasite Image in a New Browser Window Images: ...
webmineral.com/data/Thaumasite.shtml
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The Use of Limestone in Portland Cements: Effect on Thaumasite ...
1 The Use of Limestone in Portland Cements: Effect on Thaumasite Form of Sulfate Attack R. Doug Hooton 1 and Michael D.A. Thomas 2 1University of Toronto and
www.cement.org/astmc01/Reference16.pdf
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Thaumasite: Thaumasite mineral information and data.
Although it is generally assumed that a solid solution series between Thaumasite and ettringite exists, both species have different space groups and a possible ...
www.mindat.org/min-3933.html
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Sulfate attack in concrete - Understanding Cement
Overview of sulfate attack in concrete, describing conventional sulfate attack, delayed ettringite formation and Thaumasite.
www.understanding-cement.com/sulfate.html
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The occurrence of thaumasite in modern construction – a review
Jan 13, 2002 ... This paper provides a review of the reported cases of deterioration in modern construction, where the formation of the sulfate-bearing mineral ...
www.sciencedirect.com/science/article/pii/S0958946501000920
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Effect of ettringite on thaumasite formation - ScienceDirect
Dec 27, 2005 ... Deterioration of cementitious building materials is often caused by sulphate attack where ettringite and gypsum play the most destructive role at ...
www.sciencedirect.com/science/article/pii/S0008884605002784
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Thaumasite - Merriam-Webster Online
a white mineral Ca4Al6Si6O24(SO4,CO3,Cl2) consisting of a basic silicate, carbonate, and sulfate of calcium (hardness 3.5, sp. gr. 1.88) ...
www.merriam-webster.com/dictionary/thaumasite
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THAUMASITE (Hydrated Calcium Silicon Carbonate Sulfate ...
Thaumasite is a fairly rare mineral. Its chemistry and classification are interesting. It is sometimes classified as a silicate due to its silicon content and there is an ...
www.galleries.com/Thaumasite
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Thaumasite Expert Group Report: Review after ... - Planning Portal
Thaumasite Expert Group Report: Review after three years experience. Prepared by. Professor L A Clark and BRE in consultation with. The Thaumasite Expert ...
www.planningportal.gov.uk/uploads/odpm/4000000009288.pdf
Search results for "Thaumasite"
Google: approx. 45.300
Thaumasite in science
Thaumasite - Research - CMRU - The University of Sheffield
Thaumasite. Thaumasite formed at clay/PLC interface. In March 1998, serious deterioration involving the formation of the mineral Thaumasite (CaSiO3.CaCO3.
Seminar - Thaumasite - Research - CMRU - The University of Sheffield
Thaumasite Seminar. International Seminar The Thaumasite Form of Sulfate Attack of Concrete was held successfully at Centre for Cement and Concrete, ...
Aims - Thaumasite - Research - CMRU - The University of Sheffield
Thaumasite Research Aims. The aims of this project were to improve the understanding of Thaumasite formation, the reasons for its occurrence and to propose ...
[PDF]The Role of pH in Thaumasite Sulfate Attack - University of Sheffield
INTERNATIONAL SEMINAR: The Thaumasite Form of Sulfate Attack of Concrete. The Role of pH in Thaumasite Sulfate Attack. Dr Qizhi Zhou (Judith). Centre for ...
[PDF]accelerate the thaumasite form of sulfate attack - eTheses Repository
University of Birmingham Research Archive e-theses repository ... changes of the skin friction affected by the formation of Thaumasite. TSA was successfully ...
1st International Conference on Thaumasite in Cementitious Materials
Extent of immiscibility in the ettringite-Thaumasite system. Barnett, Macphee and Crammond (Aberdeen University and BRE, UK); Formation of Thaumasite in ...
[PDF]Some thermodynamic calculations related to the formation of ... - Empa
Jun 29, 2010 ... Bauhaus University Weimar. 1. introduction. 2. solubility of Thaumasite. 3. data quality. 4. calculation of reaction paths related to Thaumasite ...
Thaumasite sulphate attack on self-compacting ... - Lund University
Cutting edge, world leading, research is carried out in a wide range of subjects including medicine,nano technology, synchrotron radiation, geo sciences and ...
Thaumasite form of sulfate attack in limestone cement mortars: A ...
Jul 23, 2009 ... University of Leeds logo University of Sheffield logo York University logo ... Thaumasite form of sulfate attack in limestone cement mortars: A ...
[PDF]Thaumasite Expert Group Report: Review after ... - Planning Portal
When I presented the One-Year Review of the Report of the Thaumasite Expert ... Les Clark, Professor of Structural Engineering, University of Birmingham.
Books on the term Thaumasite
Repair, Rejuvenation and Enhancement of Concrete: ...
Repair, Rejuvenation and Enhancement of Concrete: ...
Ravindra K. Dhir, M. Roderick Jones, Li Zheng, 2002
Thaumasite is a calcium sulphate carbonate silicate hydrate formed from the reaction of sulfates with silicate and carbonate in concrete exposed to cold wet conditions. The reaction can lead to softening, expansion and cracking of concrete.
Avoiding the Thaumasite Form of Sulfate Attack: Two-Year Report (BR 385)
Avoiding the Thaumasite Form of Sulfate Attack: Two-Year Report (BR 385)
M. A. Halliwell, 2010
This report presents the results of research to give the Thaumasite Expert Group data on which to establish interim recommendations for concrete mixes designed to minimise deterioration due to the Thaumasite form of sulfate attack.
Avoiding the Thaumasite Form of Sulfate Attack: Two-year Report
Avoiding the Thaumasite Form of Sulfate Attack: Two-year Report
M. A. Halliwell, N. J. Crammond, 2010
This report presents the results of research to give the Thaumasite Expert Group data on which to establish interim recommendations for concrete mixes designed to minimise deterioration due to the Thaumasite form of sulfate attack.
PRO 35: International RILEM Workshop on International ...
PRO 35: International RILEM Workshop on International ...
Karen Scrivener, Jan Skalny, 2002
Although ettringite and Thaumasite differ in formal symmetry, the transition between them could in theory be achieved continuously: in practice solid solution appears to be incomplete; ettringite and Thaumasite solid solutions coexist. Moreover ...
PRO 33: 3rd International RILEM Symposium on Self-Compacting ...
PRO 33: 3rd International RILEM Symposium on Self-Compacting ...
Ólafur H. Wallevik, Indriði Níelsson, 2003
Nobst, P. and Stark, J.: Investigations on the influence of cement type on the Thaumasite formation. In Proceedings of the First International Conference on Thaumasite in Cementitious Materials. Building Research Establishment, 2002. 6 .
Geology and Mineral Resources of the Ivanpah Quadrangle, ...
Geology and Mineral Resources of the Ivanpah Quadrangle, ...
Donnel Foster Hewett, 1956
The heavier fraction, though less in volume, was composed of the greenish- yellow (chalcedony-yellow) mineral which, when examined under the microscope was found to be monticellite, and the white "float" or light material was Thaumasite.
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Thaumasite
Latintos: A short-hand cement chemistry notation: CS · Cs · Cc · H15 for thaumasite
CS · Cs · Cc · H15 is a widely used short-hand notation for the mineral Thaumasite [1]. In this notation, symbols CS, Cs, Cc and H15 represent the four components calcium silicate, calcium sulfate, calcium carbonate and hydrate (water), respectively, as they occur in the formula of Thaumasite's chemical composition: CaSiO3 · CaSO3 · CaCO3 · 15H2O.
golatintos.blogspot.com/2011/06/short-hand-cement-chemistry-notation-cs.html
Sulfates in Soil, Part III | Red Rock Consulting
In Part II I talked about the soil stabilization chemicals which react with sulfate-rich soils. This section covers what happens when the sulfate soil,
www.redrockgeo.com/archives/sulfates-in-soil-part-iii
£10m rotting bridge needs replacing over M5 Ι Construction Enquirer
www.constructionenquirer.com/2011/06/06/bids-invited-for-10m-m5-bridge-replacement/
The Mysteries of Maqarin | GeoSphere
We all know that cement is a man-made substance and therefore cement is always synthetic right? Wrong! In the unusual case of Maqarin, Jordan the stars aligned to produce natural cement and many of the “synthetic” minerals found therein. The Maqarin site has been the subject of an intense geological investigation by a consortium of over 100 researchers for years in an attempt to try and understand this system and its implications.
blogs.egu.eu/geosphere/2013/07/19/the-mysteries-of-maqarin/
The Study on Hydration and TSA Towards Cement-Based Material Cantaining Ultra-fine Limestone | Engineering Science Research
www.eng-paper.com/the-study-on-hydration-and-tsa-towards-cement-based-material-cantaining-ultra-fine-limestone-2/
What Is Hardcore? What Is It Used For? | Danjo Skips | Croydon
As part of Danjo Skips recycling services, construction waste is broken down into hardcore. But what is hardcore and what is it used for?
www.danjo-skips.co.uk/news/what-is-hardcore/
Silicate - New World Encyclopedia
www.newworldencyclopedia.org/entry/Silicate
Aquablue Chemistry: Pozzolan
A pozzolan is a material which, when combined with calcium hydroxide, exhibits cementitious properties. Pozzolans are commonly used as an addition (the technical term is "cement extender") to Portland cement concrete mixtures to increase the long-term strength and other material properties of Portland cement concrete, and in some cases reduce the material cost of concrete.
xplorechemistry.blogspot.com/2012/03/pozzolan.html
Mindat Mineralogy Messageboard
The web's most comprehensive and regularly updated mineralogy database with information on minerals from around the world and thousands of photos
www.mindat.org/forum.php?read,7,96788,96873
What is “Silicate” ? - LifeSun
Silicate A silicate is a compound containing an anionic silicon compound. The great majority of silicates are oxides, but hexafluorosilicate and other anions are also included. This article focuses mainly on the Si-O
lifesun.info/what-is-silicate/
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