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Gypsum exposed to high temperature exhibits significant shrinkage, which could be reduced by a suitable filler. Vermiculite is commonly used as an additive to …
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Therefore, this study uses powders in a stirred suspension at specified temperatures to determine the temperature dependence of gypsum dissolution rates. The dissolution of gypsum, (1) CaSO 4 ⋅ 2 H 2 O → Ca 2 + + SO 4 2 − + 2 H 2 O, has a standard Gibbs energy change of ΔG° = 26.1 kJ mol −1, yielding a solubility product of K …
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The mineral compositions of P 2 O 5 and F impurities in PG are hardly examined by XRD due to the low content, as indicated from Fig. 1 b. To test the phase transformation of P 2 O 5 and F impurities with different chemical compositions, firstly, 15 wt% CaHPO 4 ·2H 2 O, Ca(H 2 PO 4) 2 ·H 2 O, Na 2 SiF 6, NaF, and H 3 PO 4 in …
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Results showed that both sawdust and ash of palm tree have significantly enhanced the physical properties of gypsum cubes tested in this paper, weight, porosity, and …
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Materials. LBM, gypsum, MgCl 2, citric acid (CA), and water are used to prepare the MOCP.The mass fraction of α-MgO in LBM is 67.6%, and it is obtained by calcining magnesite at 700–900 °C.LBM is provided by Haicheng Magnesium Minerals Co., Ltd. with a specific surface area of 1274 m 2 kg −1 and an average particle size of 14.7 …
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The introduction of the European Union's climate change legislation and the intended use of renewable energy sources instead of fossil fuels will significantly reduce the production of flue gas desulfurization (FGD) gypsum used as the raw material for gypsum mortar plasters' production. This has forced mortar producers to look for alternative …
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The performance of composite gypsum at elevated temperatures depends on the treatment temperature and reflects the combined effects of gypsum phase change and the filler effects of silica flour or talc powder. Thermal treatment at ≤200 °C increased the thermal resistance of all gypsum boards but decreased their compressive strength.
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Thermal treatment at ≥300 °C significantly increased the compressive strength of gypsum with silica flour and talc powder but induced intensive microcracks and thus failed the thermal insulation. This investigation indicates that silica flour can …
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Gypsum is one of the important construction materials in Iraq in plastering surfaces and gypsum board, the ability of gypsum to give a comfortable an aesthetic ambiance as a construction material increase the need of gypsum, The particle size, total surface area and particle size distribution were factors affecting plaster properties used …
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As a first approach to evaluate the effect of high temperature on the microstructure nature of gypsum/cement binder matrix, Yu and Brouwers [18] analyzed the phases of hardened gypsum matrix's dehydration procedure by heating it to 1000 °C. It was found the microstructure of the gypsum matrix considerably changed beyond …
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mass attained a standard consistency requirements (at a flow of (100 ± 3) mm. the test was carried out by slump flow using hollow pipe with dimensions ( dia 3.5 cm and height 5.1 cm) .this test ...
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The effect of utilization of natural anhydrite gypsum type instead of natural gypsum rock on the properties of cement paste prepared from CEMI and CEMII cements was investigated by Tzouvalas et al. [17]. It was shown that natural anhydrite could efficiently retard the setting of cement with no significant change in the physico …
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This study deals with the retardation of cement setting time and workability in hot weather such as in Sultanate of Oman. Combination of sugar and gypsum was …
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retarding effect, and t his effect, controlled by Gypsum, can shorten t he long setting time caused by sugar. The setting time of cement paste was reduced from 5.5 hours to 3 hours with an ...
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It is also worth mentioning that the cation exchange capacity of soils changes with temperature, pressure, soil-solution composition, and soil ... which is a poorly graded (SP) from the arid area of Oman. They mixed 3%, 6%, 9%, and 12% by weight of gypsum with the soil and concluded that the 28 d UCS of the soil increased by about 33% after ...
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O= Plaster of Paris or (hemihydrate gypsum) At higher temperature (about 200ºC). Gypsum loses all its water of crystallization and changes to anhydrate gypsum as shown in Eq. (2). CaSO 4.2H 2 O ...
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The addition of gypsum caused an absolute increase in LOI and SO 3 content in cements, contrary to their contents from CaO, SiO 2, Al 2 O 3 and Fe 2 O 3 which decreased with the. Conclusion. The effect of gypsum content on properties of anhydrous cements, cement pastes and mortars was studied using various contents of gypsum.
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A summary of the effect of gypsum treatment on the mechanical and engineering properties of soils, including unconfined compressive strength (UCS), …
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Introduction. As a consumption industry that is high in energy and resources, Portland cement (PC) manufacture has become one of the major sources of CO 2 emissions, accounting for about 8 % of global emissions [1], [2]. With the acceleration of urbanization over the next 30 years, global cement production will reach 5 billion tonnes …
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This paper studies the different calcination temperature on the properties of titanium gypsum physical effects, and the mechanism of the effects are discussed in this paper. Research has shown that with the increase of calcination temperature, the mechanical properties of titanium gypsum present a trend of after rising first down. When the …
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When gypsum boards with no visible fibre exhibit fire-induced fall off, their cold surface temperature fell between 560 °C and 710 °C, while that for gypsum boards with obvious fibre contained ...
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The thermal properties of gypsum boards at elevated temperatures were described e.g. by Thomas [8] and by Park et al. [11] and thermal models were proposed by Thomas [6], Lázaro et al. [12] Weber [13] and Mehaffey et al. [14]. Gypsum exposed to high temperature exhibits significant shrinkage, which could be reduced by a suitable filler.
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The production of flue gas desulfurization gypsum poses a serious threat to the environment. Thus, utilizing gypsum-based self-leveling mortar (GSLM) stands out as a promising and effective approach to address the issue. β-hemihydrate gypsum, cement, polycarboxylate superplasticizer, hydroxypropyl methyl cellulose ether (HPMC), retarder, …
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Recent research has focused on investigating the influence of plastic waste on the properties of gypsum-based materials, including the quality of the interfacial …
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Geoff Thomas [11] in 2002, studied the effect of the thermal properties on gypsum plasterboard at elevated temperatures and developed a finite element thermal model for LTF walls. The thermal ...
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VARIATIONS within the normal range of temperature do not exert a very profound effect upon the rate of hydration of gypsum plaster 1,2.For example, Fig. 1 shows the maximum rate of increase of ...
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A mix containing fixed amounts of gypsum and ordinary portland cement clinker was ground in plant and laboratory ball mills to examine the effect of grinding in different mills on the cement properties.
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The study evaluated the influences of anhydrous gypsum, di-hydrate gypsum, and limestone powder on fresh properties and compressive strength of concrete with ground granulated blast-furnace …
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Chen et al. studied the thermal damage characteristics of the gypsum rock in Yingcheng, Hubei Province, and found that high-temperature (50–260°C) has a …
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Also the results indicate that cellulose fiber used in gypsum reduced the amount of deterioration of properties of fiber-reinforced gypsum (FCG) at 40 C and 200 C temperature, and the cellulosic ...
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