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Calcium aluminates

About: Calcium aluminates is a research topic. Over the lifetime, 490 publications have been published within this topic receiving 9200 citations.


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Patent
06 Feb 2019
TL;DR: In this paper, the authors used low-base calcium aluminates to increase the strength of the resulting extruded building material, utilizing waste from the production of concrete, which can be used in the manufacture of bricks, paving slabs and other small-piece products, the installation of foundations, including the foundations of roads.
Abstract: FIELD: construction.SUBSTANCE: invention relates to the field of construction and the production of building materials and can be used in the manufacture of bricks, paving slabs and other small-piece products, the installation of foundations, including the foundations of roads. Method involves crushing concrete scrap to pieces of 0.01–5.0 mm in size, moistening it to normal molding moisture, adding 5–40 % by weight of low-basic calcium aluminates with a dispersion of 2000–3000 cm/g, mixing wet concrete scrap and low-base calcium aluminates, compaction of the resulting homogeneous mixture at 10–100 MPa.EFFECT: technical result is an increase in the strength of the resulting extruded building material, utilizing waste from the production of concrete.1 cl, 3 tbl
Journal ArticleDOI
01 Jan 1954
TL;DR: In this article, the results of fundmental studies on the factors relating to the important physical properties of the special alumina cements obtained from high aluminous residue of potassium sulphate extraction of alunite ores were reported.
Abstract: In continuing the previous studies (Reports 1-6), in the present paper were reported the results of fundmental studies on the factors relating to the important physical properties of the special alumina cements obtained from high aluminous residue of potassium sulphate extraction of alunite ores.Various compounds, which can be surmised to be produced and contained in the clinker of the present special alumina cements from alunite, of calcium aluminates (mCaO⋅nAl2O3), calcium silicates (mCaO⋅nSiO2), calcium alumino-silicates (1CaO⋅mAl2O3⋅nSiO2), calcium ferrites (mCaO⋅nFe2O3), calcium alumino-ferrites (1CaO⋅mAl2O3⋅nFe2O3), ferrous silicates (mFeO⋅nSiO2), ferrous aluminates (mFeO⋅nSiO2), calcium magnesio-silicates (1CaO⋅mMgO⋅nSiO2), etc., were fully discussed and compared with those from other samples of common alumina cements, by various studying methods of microscope, X-ray analysis, separation of fine crystal powder by heavy liquide, etc.Among these results, the large amount contamination of 2CaO⋅Fe2O3 in the heavy specific gravity part (above 3.33) has the most inferior effect on the hardened strength, and the exsistences of 3CaO⋅Al2O3 and various alumino-silicates mAl2O3⋅nSiO2 (sillimanite Al2O3⋅SiO2, mullite 3Al2O3⋅2SiO2, etc.) are of most ambiguous points, which must be studied in the future studying.
Journal ArticleDOI
TL;DR: The growing of single crystals of calcium aluminates by zone melting under vacuum of 10−5 mm Hg has been studied in this article, where it is shown that some of the Al3+ ions in octahedral coordination have been driven back by the moving crystallization front.
Abstract: The growing of single crystals of calcium aluminates of compositions 12 CaO · 7 Al2O2, CaO · Al2O3, and CaO · 2 Al2O3 by zone melting under vacuum of 10−5 mm Hg permitted to establish that some of the Al3+ ions in octahedral coordination have been driven back by the moving crystallization front. Energetically, this process can be represented on the basis of the viscous flow model with the activation energy of −45 kcal/mole. The possible mathematical models have been considered for the processes of preparation of single phase crystals of the aluminates mentioned above which take account of incongruent vaporization of the component oxides and refining of the melt from structural impurities by the moving crystallization front. Die Zuchtung von Calciumaluminat-Einkristallen der Zusammensetzungen 12 CaO · Al2O3, CaO · Al2O3 und CaO · 2 Al2O3 durch Zonenschmelzen unter einem Vakuum von 10−5mm Hg erlaubte die Feststellung, das einige Al3+-Ionen in Sechserkoordination vor der Wachstumsfront hergeschoben werden. Energetisch kann dieser Prozes dargestellt werden mit Hilfe eines Modells des viskosen Fliesens mit der Aktivierungsenergie von −45 kcal/Mol. Die moglichen mathematischen Modelle wurden betrachtet fur Zuchtungsprozesse fur die einphasigen Kristalle der genannten Aluminate, die die inkongruente Verdampfung der oxidischen Komponenten und die Reinigung der Schmelze von strukturellen Beimengungen durch die Bewegung der Kristallisationsfront berucksichtigen.
Patent
27 Feb 2007
TL;DR: In this article, an ettringite binder for dense mortar, containing calcium sulphates and a mineral compound of calcium aluminates, was described, in proportions such that the useful C/A molar ratio of the mineral compound was between 1.2 and 2.7 and the weight sum of the useful phases (C+A) represented at least 30 % of the total weight of the compound.
Abstract: The invention relates to an ettringite binder for dense mortar, containing calcium sulphates and a mineral compound of calcium aluminates, said mineral compound of calcium aluminates comprising calcium C and aluminium A oxides which are soluble and combined in one or more crystallised and/or amorphous mineralogical phases, in proportions such that(i) the useful C/A molar ratio of the mineral compound of calcium aluminates is between 1.2 and 2.7 and(ii) the weight sum of the useful phases (C+A) represents at least 30 % of the total weight of the mineral compound.
Journal ArticleDOI
01 Jul 2014
TL;DR: In this paper, the strength and ions concentration in pore solution of the stabilized soils were investigated, and the results revealed that the strength of stabilized soils was almost identical as long as the calcium hydroxide (CH) concentrations in Pore Solution were saturated.
Abstract: Under the same cement content, the stabilized soils, made of the soils with similar physical properties, may be significant difference in the strength. In this research, three groups of soils were selected, and the soils in each group are similar in physical properties. Strength and ions concentration in pore solution of the stabilized soils were investigated. The result reveals that calcium hydroxide (CH) concentration in pore solution of the stabilized soils might not reach to saturation due to soil consuming Ca2+ and thus cause calcium silicate hydrates gels (C-S-H) and calcium aluminates hydrates gels (C-A-H) to form less. The cementitious hydrates are the main strength contributors of the stabilized soils. The Strengths of stabilized soils, the soils bearing similar physical properties, were almost identical as long as the CH concentrations in pore solution were saturated. The effect of chemical factors of soil on the strength of stabilized soil can be briefly attributed to the change of CH concentration in pore solution, and be further attributed to the influence of CH concentration on the amount of C-S-H and C-A-H formed in stabilized soils.

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20221
202112
202010
201914
201819
201715