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These are the three phases which can crystallize in contact with water, although it is to be remembered that the hemihydrate is a metastable phase. Gypsum occurs in several varieties: crystallized as …
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gypsum content up to 3%, for higher value of gypsum the strength starts to decrease, this is for both 0.4 and 0.5 W/C ratio, and it may b e attrib uted to the effect of setting time
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Engineering performance of asphalt pavement highly depends on the properties of bitumen, the bonding material to glue aggregates and fillers together. During the service period, bitumen is exposed to sunlight, oxygen and vehicle loading which in turn leads to aging and degradation. A comprehensive understanding of the aging mechanism of bitumen is of …
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Gypsum modification is an effective strategy to improve the water resistance of magnesium oxychloride cement paste (MOCP), but its early-ages performance evolution has not received much attention. The exothermic characteristics and hydration kinetic parameters of MOCP with different contents and types of gypsum are investigated. The …
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DOI: 10.1016/j.cemconres.2022.106860 Corpus ID: 249482156; New insights into the effect of gypsum on hydration and elasticity development of C3S paste during setting @article{Huang2022NewII, title={New insights into the effect of gypsum on hydration and elasticity development of C3S paste during setting}, author={Tingjie Huang and Qiang …
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The effect of K2SO4 activator on the hydration of chemical anhydrite obtained from burned FGD-gypsum has been studied by different experimental techniques.
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In the present work, different aging treatments were performed to investigate the pre-aging effect on the formation of Ω phase and mechanical properties in Al-Cu-Mg-Ag alloy. The results showed that pre-strain could inhibit the formation of Ω phases, which was detrimental to the alloy strength. Due to the introduction of pre-aging treatment …
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The effect of the process is determined by its conditions - the duration and relative humidity of the environment. ... As a result of aging, the strength properties of gypsum stone have increased ...
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The presence of residual C 3 A can be further associated with its higher content in the original mixtures of the M1010 series, but also with the overdosed gypsum content used, which has been found ...
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In this study, three kinds of phase structures are produced after gypsum calcination: CG150, CG350, and CG750 correspond to bassanite, anhydrite III, and anhydrite II, respectively. CG350 was the most brittle with the largest specific surface area and pore volume, followed by CG150 and CG750.
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The results demonstrate that important differences occur in the hydration of each C3A polymorph and gypsum when no lime is added; orthorhombic C3A reacts …
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Phase Change Materials (PCM) can be used for thermal energy storage, aiming to enhance building energy efficiency. Recently, gypsum plasterboards with incorporated paraffin-based PCM blends have ...
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Particular attention is paid to the presence of a cubic phase and its effect on isothermal aging. Sintering at 1550°C can result in a significant amount of large cubic grains in the specimens, that have a detrimental impact on aging resistance, especially for the first stage of the aging process. Cubic grains appear to be enriched in yttrium ...
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The paper assesses the influence of the calcination temperature of synthetic gypsum binder on the binding properties of innovative gypsum pastes, as well as on masonry and plastering mortars. The calcination process of gypsum binder was carried out at four different temperatures ranging from 170 to 190 °C. The specimens for testing …
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gypsum can affect the hydration products and hydration rate of mineral, such as alite, C 3A and ferrite phase [3–10]. The chemical reaction between C 3A and different amounts of gypsum is of great relevance as it affects the early hydration products. According to the calorimetric curves obtained for the different gypsum additions, mechanism
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In two preceding studies [14], [29] on the aging of binary C 3 A / gypsum blends at similar conditions of 90 % RH / 35 °C, the peak amount of ettringite in an aged sample was reached between 3 and 7 days of exposure, which fits the retarders' behavior in the present work. It also serves as an explanation to why the pure CEM I 52.5 N ...
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Some study results that reported the effects of adding different amounts of gypsum on the UCS of fine-grained soils (mostly clayey soils) after 7 d and 28 d of curing time are summarized in Fig. 1, Fig. 2, respectively.Two different trends are observed in …
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The synthesis of α -calcium sulfate hemihydrate (α -CSH) from flue gas desulfurization (FGD) gypsum is a good way to realize the comprehensive utilization of …
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The phase changes of gypsum were considered to be sufficiently understood for a long time. However, due to the increasing importance of gypsum recalcination (connected with the planned closure of thermal power plants resulting in a lack of FGD gypsum) and new detailed research associated with it, gaps in the current …
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This study investigates the thermal and mechanical properties that arise from aging Ni-rich Ni–Ti (Nitinol) at temperatures below 250 °C, well below those commonly used to fabricate medical devices. We demonstrate that the Ni50.8–Ti49.2 composition decomposes at temperatures as low as room temperature and discuss the unusual …
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DOI: 10.1016/j.jobe.2020.101801 Corpus ID: 225317559; Effect of wetting-drying cycles on gypsum plasters containing ground basaltic pumice and polypropylene fibers @article{Durgun2020EffectOW, title={Effect of wetting-drying cycles on gypsum plasters containing ground basaltic pumice and polypropylene fibers}, author={Muhammed Yasin …
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β-HPG was used as the main cementitious material to prepare eco-friendly gypsum composites in this work. The crystal phase composition of β-HPG is depicted in Fig. 1 (a), which mainly includes a large number of CaSO 4 ·0.5 H 2 O and partial SiO 2.As can be seen in the scanning electron microscope image (Fig. 1 (b)), the crystal …
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Highlights. •. Freezing-thawing and wetting-drying accelerated aging tests are considered to simulate outdoor conditions. •. Two straw-gypsum plaster composites …
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After the induction period, the behavior changes and gypsum enhance the C 3 S hydration [6,8,18,19,[51][52][53][54][55] [56] [57]; see Fig. 4. Yamashita et al. [58] have observed that increasing ...
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Incorporating a small amount of gypsum affects the formation and growth of hydrates and the compositions of aqueous phases in fresh C 3 S paste during the …
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Fig. 1 shows the XRD pattern of FGD gypsum raw materials, which indicates that the main phase of FGD gypsum is calcium sulfate dihydrate. The morphology of FGD gypsum is given in Fig. 2.As illustrated in Fig. 2 a, the FGD gypsum has large particles with an average particle size distribution of about 60 μm. Fig. 2 b clearly reveals that …
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Request PDF | On Nov 4, 2021, Kechang Zhang and others published Improvement of the Hydration Kinetics of High Ferrite Cement: Synergic Effect of Gypsum and C 3 S–C 4 AF Systems | Find, read and ...
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The effects of phosphoric acid (H3PO4) in pressurized aqueous solution on the dehydration of CaSO4·2H2O to form α-hemihydrate gypsum (α-HH) phase and the regulation of crystal shape …
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Alkali substituted C 3 A converted to ettringite faster and more completely than pure C 3 A. Ettringite from prehydration caused a seeding effect, which promotes crystal growth and …
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To promote the recycling of industrial waste and produce ultra-low carbon energy storage materials with low-energy consumption this work innovatively proposes to capture carbon dioxide using the mixture made of 70 wt% desulphurization gypsum and 30 wt% carbide slag via a aqueous solution method, and the carbonized mixture used as …
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