• Thaumasite - Wikipedia

    en.wikipedia.org/wiki/Thaumasite Thaumasite is a silicate mineral with chemical formula Ca 3 Si(OH) 6 (C O 3)(SO 4)·12H 2 O.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.
  • Thaumasite: Mineral information, data and localities.

    www.mindat.org/min-3933.html Although it is generally assumed that a solid solution series between thaumasite and ettringite exists, both species have different space groups and a possible discontinuity was identified, characterised by a gap in the a-dimension of the solid solution phases (Barnett et al., 2000). Further work showed a miscibility gap in the solid solution (Barnett et al., 2003): ettringite can accept the ...
  • Thaumasite sulfate attack on concrete: Mechanisms ...

    www.sciencedirect.com/science/article/pii/S0950061814010502 Thaumasite (C 3 S S ¯ C ¯ H 15) is a rare naturally occurring mineral comprising complex hexagonal crystal structure of sulfate salt, usually found in metamorphic rocks and limestone , .It is composed of calcium silicate, carbonate, sulfate, and water. Erlin and Stark first reported thaumasite formation (TF) in portland cement concrete in 1965. It was found in sanitary sewer pipes, portland ...
  • Sulfate attack in concrete - Cement

    www.understanding-cement.com/sulfate.html Thaumasite can occur rarely as a natural mineral as an alteration product of limestones. Thaumasite can form in concrete and in mortar. The cement hydration products normally present, mainly calcium silicate hydrate and calcium hydroxide, are decomposed as a result of both sulfate attack and of carbonation.
  • Thaumasite Meaning & Use: Stimulates The Mind, Helps ...

    www.healing-crystals-for-you.com/thaumasite.html Thaumasite Stimulates The Mind To Enhance Thinking, Helps Problem Solving. Written By Liz Oakes. Thaumasite is stimulating to the mind and can enhance your thinking and may create a new way of thinking. This is a strong spiritual stone that may assist you to gain a greater understanding of why you are here.
  • Thaumasite | Definition of Thaumasite by Merriam-Webster

    www.merriam-webster.com/dictionary/thaumasite Thaumasite definition is - a white mineral Ca4Al6Si6O24(SO4,CO3,Cl2) consisting of a basic silicate, carbonate, and sulfate of calcium (hardness 3.5, specific gravity 1.88).
  • Thaumasite - definition of thaumasite by The Free Dictionary

    www.thefreedictionary.com/thaumasite Shehata, "Mineralogical and chemical assessment of concrete damaged by the oxidation of sulfide-bearing aggregates: Importance of thaumasite formation on reaction mechanisms," Cement and Concrete Research, vol.
  • MPA Cement Fact Sheet 2 Thaumasite form of sulfate attack ...

    cement.mineralproducts.org/.../FS_2_Thaumasite_form_of_sulfate_attack.pdf Thaumasite Expert Group, The thaumasite form of sulfate attack: Risks, diagnosis, remedial works and guidance on new construction. DETR 1999 Building Research Establishment, Concrete in aggressive ground. Special Digest SD1, Third Edition, 2005 MPA Cement Mineral Products Association Gillingham House 38 – 44 Gillingham Street London SW1V 1HU
  • Thaumasite sulfate attack on concrete: Mechanisms ...

    www.sciencedirect.com/science/article/abs/pii/S0950061814010502 Thaumasite sulfate attack (TSA) is a special form of sulfate attack typically occurring due to the availability of carbonates/bicarbonates in the cementitious matrix with abundance of moisture and a prevailing low temperature. It transforms concrete into a non-cohesive mass without any binding or load carrying capacity.
  • Thaumasite - Mindat.org

    www.mindat.org/gm/3933 Thaumasite is a very rare silicate/carbonate/sulfate mineral, and to find a specimen this good marks a notable occasion. The color in real life is a straw-yellow hue, quite clear in person. The gemminess and aesthetics make this a striking thumbnail 1.4 x .7 x ...