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A typical low-calcium fly ash was used as additive in mortar, replacing part of the volume either of Portland cement or aggregate. The development of the strength, heat, porosity, bound water, and calcium hydroxide content was measured.In aggregate replacement higher strengths were observed after 14 days, whereas in cement replacement higher strengths were …
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Fly ash (FA) is a pozzolanic material that commonly used as a starting material for geopolymer synthesis. In Thailand, high calcium fly ash has been widely investigated as source material for geopolymer synthesis [9-12] Lightweight concrete is one of construction material that is widely used in a house-building.
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The history of magnesium oxysulfate (MOS) cement began with a patent granted in 1891 to Enricht for "artificial stone or cement". MOS cement is an air-dried magnesia-based material produced by the reaction of magnesium oxide, magnesium sulfate and water [1], [2], …
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i (Kanpur) fly ash has low calcium (2.4) and low carbon (2.55%). The fly ash from Neyveli Lignite Corporation (Neyv. li) was of high calcium (16.85%) and low carbon (1.45%) variety. …
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According to ASTM C618, a fly ash with at least 18% CaO is classified as a high-CaO fly ash. A fly ash with less than 18% Cao is classified as a low-CaO fly ash or Class F …
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Ground lignite bottom ashes (BAs) with median particle sizes of 16, 25, and 32 μm were used. NaOH, sodium silicate, and temperature curing were used to activate the geopolymerization. Results showed that relatively high strengths of 40.0–54.5 MPa were obtained for the high-calcium bottom ash geopolymer mortars.
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Although high calcium fly ash can be used as a source material for geopolymer binder, it has rarely been studied with other wastes especially, glass wool waste. Therefore, this study presents the use of glass wool (GWF) from the insulating materials waste and high calcium fly ash (HCFA) as binary precursors to produce geopolymer paste.
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Sulfate attack is one of the major threats to concrete structures. In this study, strength degradation, by magnesium sulfate (MgSO 4) reaction, of low-calcium fly ash geopolymer-hemp shiv concrete was carefully investigated.The hemp shiv was pretreated with AlCl 3-KOH to prevent water absorption.Air and water curing were also performed to elucidate …
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The results of the XRF test are reported in Table 3.Both fly ash samples were found to be high calcium fly ash (class C), with total content of SiO 2 + Al 2 O 3 + Fe 2 O 3 of 67.8% and 66.29% for FA1 and FA2, respectively, and the CaO level of more than 10% and with a very low loss on ignition (LOI) value. FA2 has higher CaO content than FA1.
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The objective of this study is to investigate the effectiveness of replacing nano-SiO 2 with rich husk ash for improving the performance of recycled aggregate geopolymer concrete (RAGC) made from high-calcium fly ash that is able to set and harden without heat curing. The mechanical properties and fire-resistant performance of RHA-added and nS ...
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Waste minimization is a major approach whereby many industries decrease environmental pollution and promote cleaner production. To achieve sustainable development, a novel idea is proposed herein to recycle magnesium slag (MS) and high-calcium fly ash (FA) into cementitious materials which are then mixed with aeolian sand (AS) to produce a type of …
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To expand the application range of magnesium oxysulfate cement (MOSC) and the utilization of fly ash, the water resistance of MOSC mixed with low-calcium fly ash (L-FA) or high-calcium fly ash (H ...
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Effect on Strength Characteristics of Low Calcium Fly Ash 175 expensive except fly ash, further Low calcium (ASTM Class F) fly ash is preferred as a source material than high calcium (ASTM Class C) fly ash. The presence of calcium in high amount may interfere with the polymerisation process and alter the microstructure (Gourley 2003).
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Lightweight geopolymer (LG) block was fabricated from high calcium fly ash and recycled aggregate.. LG with NH = 5–15 molars, NS/NH = 0.33–3, liquid/ash = 0.5–1, curing at 25–60 °C, aggregate content = 0.85–1.05 %wt. were tested.. Low densities of 1000–1300 kg/m 3 and 28-day compressive strengths of 4.0–11.2 MPa were obtained.
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High calcium fly ash geopolymer pastes containing diatomite as additive. Tanakorn Phoo-ngernkham. See full PDF download Download PDF. Related papers. Properties of high calcium fly ash geopolymer pastes with Portland cement as an additive.
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High-calcium fly ash produced from low-temperature combustion of fuel, like in circulating fluidized bed technology, reacts with water readily and is itself a good hardening activator for GGBFS ...
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The fundamental requirements of high ... the good mix design, inadequate compaction significantly ... Characteristics of Low-Calcium Fly ash-based
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A high-calcium fly ash (FH, 23% total CaO–5% free CaO), with high SO 3 content (4.3%), was studied as additive in mortar, replacing part of the volume either of Portland cement or aggregate. The development of the strength, porosity, bound water, and calcium hydroxide content was measured.
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The heterogeneous composition of lignite fly ash complicates its utilization as an admixture to concrete. The reactivity of lignite fly ash is related to the occurrence of reactive glassy components and several cement phases. Glassy spheres and anhydrite in the micrometer and submicrometer range of lignite fly ash were analyzed with AEM methods.
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Under the same adsorbent dosage, the removal efficiency of regenerated zeolite was lower than the initial zeolite by 25.02% and 1.2% for zeolite converted from high-calcium fly ash and low-calcium ...
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Low-calcium fly ash has been successfully used to manufacture geopolymer concrete when the silicon. and aluminum oxides constituted about 80% by mass, with the Si-to-Al ratio of about 2. …
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Calcium carbonate (CaCO 3) is a carbonate species among the carbonate minerals and is abundantly available in nature.It exists in three anhydrous crystalline polymorphs: vaterite, aragonite and calcite. Calcite, in particular, is found in some animals and helps strengthen bones [31].An inert particle called calcite, often derived from limestone, can …
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Geopolymer is a ceramic-like material produced by the combination of alumino-silica source material and alkaline activator.High calcium fly ash is an emerging binding material for production of geopolymer while there is currently growing potential to use recycled clay brick as part of the binding material as clay brick is also inherently a ceramic-type material.
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High calcium fly ash (HCFA) from thermal power plants is a good replacement for Portland cement, but its properties vary greatly depending on particle size and composition. The industrial HCFA fractions (Fr1-Fr4) taken from four fields of electrostatic precipitators (EP) of the ash collection unit of the Krasnoyarsk thermal power plant (TPP-2 ...
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The higher compressive strength achieved by OPG synthesised in this study is because of the lower water content in this mix system and the high CaO content in the fly ash used that was able to yield calcium-containing hydrate gel, which was compact and contributed to a better mechanical properties [27]. The finding of this study suggests that ...
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The physical properties and chemical compositions of fly ash are largely influenced by the types of coal-firing and collection devices [12]. According to the content of CaO, two classes of fly ash are specified: ordinary low-calcium fly ash or "Class F" (CaO < 10%) (L-FA) and high-calcium fly ash or "Class C" (CaO > 10%) (H-FA) [13], [14].
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In this research effort, the role of calcium in geopolymers was investigated through a series of syntheses where a high-calcium fly ash was blended with a low-calcium …
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FA, TG, natural gypsum (NG), and CCR were used in this study. The fly ash (FA) utilized in this study was commercially available class-F fly ash from the thermoelectric power plant located in Jiaozuo [24, 25], while the carbide calcium residue (CCR) was provided by Henan Energy and Chemical Industry Group Co., Ltd. TG was donated from the TG stockpile …
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Hwang and Shahsavari (2019) investigated the optimization of a high calcium cementless fly ash (FA) binder with a low environmental footprint. Their optimized composition comprising of FA and ...
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High calcium fly ash was used as the primary binder in this investigation. The chemical components of the high calcium fly ash used were detected by X-Ray fluorescence (XRF) and presented in Table 1. The fly ash was acquired from the Manjung Power Plant in Perak, Malaysia as a source of aluminosilicate materials for the production of one-part ...
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