In concrete chemistry, ettringite is a hexacalcium aluminate trisulfate hydrate, of general formula when noted as oxides: 6CaO·Al2O3·3SO3·32H2O or, 3CaO·Al2O3·3CaSO4·32H2O. Ettringite is formed in the hydrated Portland cement system as a result of the reaction of tricalcium aluminate (C 3A) … See more Ettringite is a hydrous calcium aluminium sulfate mineral with formula: Ca6Al2(SO4)3(OH)12·26H2O. It is a colorless to yellow mineral crystallizing in the trigonal system. The prismatic crystals are typically … See more The mineral ettringite has a structure that runs parallel to the c axis -the needle axis-; in the middle of these two lie the sulfate ions and H2O molecules, the space group is P31c. Ettringite crystal system is trigonal, crystals are elongated and in a needle like shape, occurrence … See more • Cement • Cement chemists notation • Concrete See more Ettringite was first described in 1874 by J. Lehmann, for an occurrence near the Ettringer Bellerberg Volcano, Ettringen, Rheinland-Pfalz, Germany. It occurs within metamorphically altered limestone adjacent to igneous intrusive rocks or within xenoliths. It also occurs as See more Ongoing research on ettringite and cement phase minerals is performed to find new ways to immobilize toxic anions (e.g., borate, selenate and arsenate) and heavy metals to … See more WebJan 1, 1992 · Reactions between time, alumina released from clay during pozzolanic reactions, and sulfates present in some soils (causing the formation of the highly expansive crystalline mineral...
Ettringite review PDF Cement Concrete - Scribd
WebEttringite occupies a larger volume than AFm phase and crystallizes under the form of acicular needles. This reaction is expansive and can cause a huge crystallization pressure in the small concrete pores once they are totally filled by the growing ettringite crystals. WebDEF is a result of high early temperatures (above 70 o C – 80 o C) in the concrete which prevents the normal formation of ettringite. DEF-induced damage is not a common phenomenon in concrete. Water or moisture from an external source is required for the reaction to occur, the availability of which will affect both the rate and the extent of ... firefox text mode
Ettringite - Wikipedia
WebEttringite or hydrated calcium aluminum sulfate hydroxide (Ca 6 Al 2 (SO 4) 3 (OH) 12 ·26H 2 O) is formed by the reaction between sulfate ions and the aluminate phases … WebFeb 23, 2016 · Ettringite (Ca 6 Al 2 (SO 4) 3 (OH) 12 ·26H 2 O) is a naturally occurring compound in calcium-rich, alkaline environments, which is found as a secondary mineral … WebFeb 23, 2016 · Ettringite is a crystalline acicular material formed of columns of calcium and aluminum double hydroxides, whose residual charges are stabilized by sulfate ions and water molecules positioned among these columns. firefox text is blurry