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(PDF) Late anhydrite cements mark basin inversion: isotopic and
Isotopic analyses of texturally late intergranular and fracture-filling anhydrite suggest waters very similar to the present day formation waters. 634S values of anhydrite cements (+10%o CDT) indicate that sulphate in the Rotliegend originated from the stratigraphically overlying Zechstein evaporites. The (87Sr/86Sr)15o...
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Influence of Anhydrite on the Properties and Microstructure …
Keywords: hydraulic cementitious material; aluminophosphate cement; anhydrite; compressive strength; pore analysis 1. Introduction Ordinary Portland cement (OPC) is the most common building material in today's construction engineering and a crucial component of infrastructure projects and the de-veloping economy.
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Screed: Everything You Need to Know
Liquid cement screeds are applied in the same way as anhydrite and laid to the same thickness. They have similar properties to anhydrite: they are self-compacting, quick to lay and UFH-compatible. Manufacturers claim they are quicker to dry, even in adverse conditions, and can be tiled with little or no surface preparation.
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Hydration mechanisms of supersulfated cement | SpringerLink
Supersulfated cement (SSC) made with high activator content (0.8%) promoted a more intense hydration kinetics at early ages improving the compressive strength, in special at 24 h. However, since 7 days, a lower mechanical performance was verified, and it was associated with a faster consumption of anhydrite and formation of …
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(PDF) A syngenetic classification of anhydrite textures in …
Two phases of anhydrite cementation were recognised in this study: Phase I is represented by syndepositional anhydrite cement that affected the reservoir quality of the tidal flat facies, and ...
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Calcium Sulfate
Gypsum was first used with Portland cement to retard the rate of setting sufficiently to permit the proper placing of mortar and concrete. It is recognized that gypsum and calcium sulphate, in general, can play an important role in the manufacture of clinker as mineralizer or modifier for the recycling of alkalis. ... Anhydrite, CaSO 4, is a ...
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Activation of gypsum anhydrite-slag mixtures
Gypsum anhydrite-slag mixtures were produced by blending anhydrite with granulated blast furnace slag, Ca (OH) [sub 2] and small amounts of Na [sub 2]SO [sub 4] [center dot] 10H [sub 2]O and FeSO [sub 4] [center dot] 7H [sub 2]O as activators. A mechanism of conversion of anhydrite into gypsum through transient double salts in …
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Activation of gypsum anhydrite-slag mixtures
Gypsum anhydrite-slag mixtures were produced by blending anhydrite with granulated blast furnace slag, Ca (OH) 2 and small amounts of Na 2 SO 4 · 10H 2 O and FeSO 4 · 7H O as activators. A mechanism of conversion of anhydrite into gypsum through transient double salts in presence of activators is suggested. Activation of granulated …
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Effects of different gypsum varieties on the hydration and …
Anhydrite and DSG were used to adjust the hydration of RFSAC clinker in this study. The anhydrite used in the experiment was from Shengwei Special Cement Co., LTD., Shandong Linqu, and DSG was from Shanshui Group Co., LTD. Using XRD to test the mineral composition of the two gypsum. The results were shown in Fig. 1. The …
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Minimum thickness screed
Anhydrite screed is no less than three times as strong as cement-based screed. Due to its strength, the minimum thickness of anhydrite screed is slightly lower. For an adhering anhydrite screed you can start from a thin screed with a minimum thickness of 30 mm. For a non-adhesive anhydrite floor, the minimum thickness is 40 mm.
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A syngenetic classification of anhydrite textures in carbonate
Many studies have indicated the presence of anhydrite as a cement in carbonate reservoirs (e.g., Saller and Henderson 1998; Melim and Scholle 2002; Lucia et …
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Making of anhydrite cement from waste gypsum
The formation of anhydrite cement was examined by microscopy and X-ray diffraction. Data showed that a stable anhydrite can be produced by heating phosphogypsum at 1000°C. The effects of different chemicals on setting and hardening …
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Influence of limestone and anhydrite on the hydration of Portland
The cement clinker was ground together with the anhydrite in the laboratory ball mill. The cement clinker was homogenized with 15 wt% of ground limestone and different quantities of natural anhydrite (2.5, 3.5 and …
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Analysis of anhydrite gypsum effects on quality of cement
With respect to learn effects of gypsum and anhydrite on cement parameters, the physical and mechanical parameters of cement samples which is mixture of clinker-gypsum and clinker-anhydrite with 4.0, 4.5, 5.0, 5.5 and 6.0% are investigated. 3.1. Fineness and grinding time of cement samples
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Hydration mechanism of calcium sulfoaluminate-activated …
This cement consists of 80% granulated blastfurnace slag (GBFS), 15% anhydrite, and 5% high-belite calcium sulfoaluminate cement (HB-CSA) clinker. The hydration mechanism of CSA-SSC was experimentally investigated using isothermal calorimetry, X-ray diffraction, thermogravimetric analysis, and scanning electron …
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Effects of alternative calcium sulphate-bearing materials on cement
1. Introduction. Role of cement retarders is to prevent C 3 A and water fast reaction, that's why natural gypsum is grinded and blended with clinker in cement mills with the different additives according to the cement type. Gypsum hemihydrate and anhydrite exists in nature same as gypsum and can replace gypsum partially or completely in …
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ANHYDRITE IN CLINKER | Role of Cement Science in …
ANHYDRITE IN CLINKER. There are contradicting opinions about the behaviour of concrete made of cement produced of clinker containing anhydrite. …
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Environmental and sequence stratigraphic implications of anhydrite
The anhydrite cements (poikilotopic, pervasive and fracture filling anhydrite cement), that are common in lagoon and shoal facies, affected the reservoir units and reduced the poroperm values. The poikilotopic and pervasive cements occluded or decreased some of the precursor pore spaces by filling pore throats imparting low …
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Study of aluminum sulfate and anhydrite on cement hydration
Setting regulator used in Portland cement is anhydrite in this research. Due to the low dissolution rate of anhydrite, sulfate is insufficient during the hydration process of C 3 A, so the existing period of amorphous AFm before the formation of AFt is prolonged. In present study, in control cement paste, before 24 h of hydration, the main ...
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Making of anhydrite cement from waste gypsum
1. The stable anhydrite cement can be produced by heating phosphogypsum at 1000°C. 2. The microstructure of anhydrite cement shows the formation of euhedral prismatic and rhombic shaped crystals of platy structure. 3. Maximum attainment of compressive strength in anhydrite cement is achieved with the use of sodium sulfate …
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Cement hydration
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Dehydration Pathways of Gypsum and the Rehydration …
The dehydration products of gypsum under different temperature and water vapor pressure were investigated by thermodynamic theory. Additionally, the rehydration mechanism of soluble anhydrite was also studied by Monte Carlo (MC) simulations. The thermodynamic calculation results reveal that the dehydration mechanism of gypsum …
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Analysis of anhydrite's effects on quality of cement
This paper briefly describes the results of utilization of natural anhydrite in cement pastes of CEM-I and CEM-II types. The aim of the study has …
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Common well cements and the mechanism of cement-formation …
This article reviews the common well cements and describes the basic nature of the cement-formation bond in zonal isolation and its effects on the mechanical and hydraulic performance. The cements are Classes G and H Portland well cements. The cement-formation interface bonding mechanism is a combination of the mechanical indentation of …
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Research status of super sulfate cement
Cement is one of the most popular building materials used all over the world. The produce of traditional cement requires huge mineral resources as raw material and fossil energy as fuel, followed by massive emission of greenhouse gases. ... Anhydrite and dihydrate gypsum have similar effect on the hydration evolution of SSC (as shown in Fig. …
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Petrographic and geochemical constraints on the formation and
Anhydrite cement is present in Upper Jurassic sandstones in the Gulf of Mexico as poikilotopic masses in which detrital grains are replaced and as smaller …
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Recycling of phosphogypsum to prepare gypsum plaster
The preparation of anhydrite from PG had a lower energy consumption compared to the traditional building materials. Besides, as is well known, the production of each ton of ordinary Portland cement will emit 0.7–0.8 tons of carbon dioxide [51]; thus, it is conducive to reduce the economic burden caused by "carbon trading".
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Effects of sulfates on the hydration of Portland cement – A review
Calcium sulfate is used in Portland cement to control the C 3 A reaction to induce the optimum hydration of C 3 S to occur. The amount of calcium sulfate in the Portland cement influences the hydration, rheology, setting, phase assemblage, porosity distribution, and strength in cementitious materials. If added in excess, it can also lead to ...
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Hydration and mechanical properties of FGD gypsum-cement …
The simplex-centroid design method [28] with upper and the lower bounds of component ratio is a design method for concrete composition based on multiple performance requirements that could gain the optimal composition of cementitious system.By comparing the variation of the compressive strength and softening coefficient of gypsum-cement …
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Anhydritec
About Us. Anhydritec is a Business Unit of the Minersa Group, producer of industrial minerals and chemical products.Minersa is one of the largest producers of synthetic anhydrite in Europe. Anhydritec is a European leader in anhydrite technologies for all type of applications and markets, from construction (flowing screeds) through industrial …
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