Ettringite: Mineral information, data and localities.
Ettringite Group. Although it is generally assumed that a solid solution series between ettringite and thaumasite 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): …
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Physicochemical properties of ettringite/meta-ettringite …
Ettringite, of which chemical formula is 3CaO·Al 2 O 3 ·3CaSO 4 ·32H 2 O, or C 6 A S ¯ 3 H 32 as known in cement chemistry notation, is also named as calcium trisulfoaluminate hydrate or AFt in whose group ettringite is one of the most important members. It has a lower density (~ 1.77 g cm −3) and contains more water (~ 46%) than any other cement-based …
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Ettringite: Influence of Steam Curing and Excessive Sulphate …
Most of IBS manufacturers adopt steam-curing method for rapid hydration process, in which evolves cracking features due to the formation of ettringite and caused expansion at early age. This paper investigates the ettringite formation under the excessive sulphate...
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Environmental Impact Assessment of Soil Stabilization Materials …
Fly ash used in the study was locally acquired from a geo-thermal plant. Tables 2 and 3 list out the physical and chemical properties of fly ash used during the course of study. The physical and chemical properties of fly ash are attractive for many civil engineering applications, such as usage in concrete production or soil stabilization.
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Enhancing marl soil stability: nanosilica's role in mitigating
This article aims to assess the impact of nanosilica on the formation of ettringite and the nanostructure of calcium silicate hydrate (C-S-H) during the marl soil stabilization process with lime. ... Nanosilica addition aims to boost CSH gel production and prevent ettringite formation during pozzolanic or cement hydration, potentially reducing ...
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Ettringite Mineral Data
Moore A E, Taylor H F W, Acta Crystallographica, Section B, 26 (1970) p.386-393, Crystal structure of ettringite, Locality: Scawt Hill, Northern Ireland Physical Properties of Ettringite Cleavage:
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Experimental Studies on Ettringite-Induced Heaving in Soils
Ettringite formation and subsequent heaving in soils are complex topics that are not well understood. This research is an attempt to advance the state of the knowledge on these topics. ... for providing SEM and XRD equipment access to the present research. ... Burkart, B., Goss, C. G., and Kern, P. J. (1999). "The role of gypsum in production ...
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Ettringite Cements Its Potential | Feature
Researchers have identified a process that makes it possible for a mineral in cement—ettringite—to incorporate and hold the radioactive contaminant pertechnetate. The discovery could prove to be an important …
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Structural and spectroscopic characterization of ettringite mineral
Although thaumasite and ettringite are from the same family of minerals, several differences exist between their structures. Apart from the hexagonal structure of thaumasite (space group P6 3), the ettringite structure is trigonal (space group P31c). Further, ettringite contains Al atoms instead of Si, and three SO 4 2 − anions and two H 2 O molecules replace …
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Delayed Ettringite Formation | Concrete Experts International
What is Delayed Ettringite Formation? Generally DEF is seen as a form of internal sulfate attack. A number of factors such as concrete composition, curing conditions and exposure conditions influence the potential for DEF. DEF is believed to be a result of improper heat curing of the concrete where the normal ettringite formation is suppressed.
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Experimental study of delayed ettringite formation under …
The amount of ettringite production at different temperatures. Concerning the thermal stability of ettringite crystals, many studies have suggested that the decomposition temperature of ettringite is generally considered to be 70–80 °C [27,32,39,40]. To investigate the temperature limit and the generation of ettringite, the temperature ...
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Application of Steel Slag as an Aggregate in Concrete Production …
Steel slag is a solid waste produced in crude steel smelting, and a typical management option is stockpiling in slag disposal yards. Over the years, the massive production of steel slags and the continuous use of residue yards have led to vast occupation of land resources and caused severe environmental concerns. Steel slag particles can potentially be …
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Effect of ettringite morphology on the properties of …
analyzed [13, 14]. It is known that the reaction of formation of ettringite develops in accordance with the equation: 2С3А + 3CaSO4×2H2O + 26H2O = 3CaO×Al2O3×3CaSO4×32H2O Or 6 Сa2+ + 3 SO 4 2-+ 2Al3+ +12 OH-+ 26H2O = 3CaO×Al2O3×3CaSO4×32H2O One of the basic provisions of physical chemistry should be borne in mind, according to
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Kinetic model to predict cement susceptibility to delayed ettringite
R e rate of production of ettringite. ... equipment (Ekolu, 2004; Lawrence, 2003). In addition, this. technique has the advantage of reducing creep, shrinkage and loss.
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Ettringite instability in supersulfated cement: Investigation …
It is known that the primary hydration products of SSC are ettringite and calcium-silicate-hydrate (C–S–H), and the instability of the former has been observed in some studies. Thus, the aim of the present study was to investigate the influence of the SSC curing process on the formation of ettringite. ... SDT Q-600 equipment was used, and ...
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Bottom Ash: Production, Characterisation, and Potential for …
Specific separation equipment was used for the 0–2 and 2–6 mm granular fractions while standard magnetic drums and eddy current separators were used for the larger fractions (6–20 and 20–40 mm). Table 20 shows the various specific equipment used for the treatment of fractions of IBA in fractions 0–2 and 2–6 mm.
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The mechanism of the formation and transformation of …
ettringite depends on the ion concentration in liquid phase, i e, thermodynamic condition in the system. 3.3 Effect of gypsum addition on the stability of ettringite By addition of various amount of CsH2 (PA:2.0% S03, PB:4.0% S03) into cement clinker with 15% C3A content, the effect of gypsum addition on the stability of ...
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Cement-Admixture Incompatibility
The hydration product that we would normally like to see form in this initial phase is a mineral called ettringite. But if a sufficient amount of the inter-ground gypsum used to control flash set is not present when the cement and water are mixed together, the highly undesirable aluminate hydrate forms.
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Delayed etttringite formation in concrete (DEF)
of ettringite. Cooling followed by prolonged exposure to moist conditions can, in some circumstances, cause the slow formation of ettringite. Where has DEF been found? The most common occurrence of DEF worldwide has been in heat cured precast concrete components, such as railway sleepers. It is estimated that DEF may also have occurred in
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Mechanistic Insights into a Sustainable …
Ettringite production would, therefore, benefit greatly from the development of new synthetic pathways, economically viable and fulfilling current ecological requirements. ... weight 3 g) to exclude the incorporation of iron …
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Delayed etttringite formation in concrete (DEF)
What is delayed ettringite formation (DEF)? DEF is expansion and cracking of concrete associated with the delayed formation of the mineral ettringite (a hydrated calcium …
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Experimental Studies on Ettringite-Induced Heaving in Soils
Ettringite was successfully synthesized in the laboratory by simulating conditions close to those in chemically treated sulfate-bearing soils. Soils spiked and compacted with the …
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First-principles investigations of arsenate doping into the ettringite …
DOI: 10.1016/j.jclepro.2023.138266 Corpus ID: 260231000; First-principles investigations of arsenate doping into the ettringite lattice @article{Zhao2023FirstprinciplesIO, title={First-principles investigations of arsenate doping into the ettringite lattice}, author={Yingliang Zhao and Yong Sun and Zhenbang Guo and Jingping Qiu and Xiaogang Sun}, journal={Journal of …
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Mechanistic Insights into a Sustainable …
An environmentally friendly mechanochemical synthesis of ettringite was developed which combines the advantages of a high conversion/short reaction time (94 % in 2 h) with no CO 2 release or waste …
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Ettringite – Wikipedia tiếng Việt
Ettringite là một khoáng chất calci nhôm sulfat với công thức: Ca 6 Al 2 (SO 4) 3 (OH) 12 ·26H 2 O. Nó là một khoáng chất từ không màu đến màu vàng kết tinh hệ tinh thể lục phương.Các tinh thể lăng trụ này thường không có màu, biến thành màu trắng khi mất nước một phần. Nó là một phần của nhóm ettringite bao gồm các ...
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A literature review on delayed ettringite formation: …
The expansion deterioration that occurs in concrete structures exposed to high temperature fluctuation in wet environments is often attributed to delayed ettringite formation (DEF). Due to the complex mechanism and various factors that influence DEF, it is difficult to establish effective methods for predicting the expansion and suppressing deterioration. With …
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Modelling the Kinetic Behaviour of Delayed Ettringite …
The expansion data sets were sourced from the data published in [].A summary of the experimental process is given here. The GP cement was compliant with AS 3972 and ATIC specifications (0.47% Na 2 O e, 2.6% SO 3).The C 3 A content was estimated to be 7.9 wt% using a modified Bogue's method. In order to develop expansion in the concrete prisms due to …
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First-principles investigations of arsenate doping into the ettringite …
Journal of Cleaner Production. Volume 419, 20 September 2023, 138266. First-principles investigations of arsenate doping into the ettringite lattice. ... Ettringite (Ca 6 Al 2 (OH) 12 (SO 4) 3 ∙26H 2 O) is one of the main components of hydrated cement and is known to stabilize anionic species. Thus, it is a promising material for the ...
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Ettringite formation and microstructure of rapid hardening …
Ettringite production and microstructure The amount of ettringite produced during hydration was calculated using the following equation: Ettringite (%)=100R h E s (100−L s )/R s E h (100−L h ) where R h and R s are the XRD peak areas of ettringite and internal standard, respectively, for the hydrated sample, and E h and E s are the peak ...
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Delayed Ettringite Formation
Delayed ettringite formation (DEF) may be defined as the formation of ettringite in a cementitious material by a process that begins after hardening is substantially complete and in which none …
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