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low calcium fly ash from eastern bituminous coal increased with increase of pH in the alkaline pH range (pH 7 – 12). Fly ash from eastern bituminous coal with a ... #1005 and #1004; acidic ash #1009 has a calcium content about twice as high as the other two acidic ashes. Correspondingly, the soluble calcium concentrations
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In this study, the effects of low-calcium fly ash (LFA) and high-calcium fly ash (HFA) on C–S–H structure, hydration products, hydration heat, and compressive strength of …
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AbstractThis study investigated the performance of alkali-activated, cement-based controlled low-strength materials (CLSMs). The CLSM was produced by mixing fly ash, steel slag, sodium hydroxide, and water with bottom ash (BA) aggregate. Properties of ...
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The results indicated that the inclusion of 10%–30% slag resulted in a stronger CLSM with a higher Ca/Si ratio in the cementitious matrix of its microstructure. Higher slag …
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durability properties of high-calcium fly ash-based geopolymer concrete containing RCA. The low-calcium bentonite is a naturally found pozzolana, rich in silica and alumina, that has been extensively used for many years to improve the mechanical and durability properties of conventional concrete [34,35].
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In normal and high-strength concrete, low-calcium fly ash (FL) is a mineral admixture that has been widely used. Due to pozzolanic activity in a fly ash alumino-silicate glass phase, hydration is much more complex in cement blended with fly ash than in ordinary portland cement. A kinetic hydration model is presented in this paper which has its basis in a multi …
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Among the latter, high–calcium fly ashes (HCFA) from coal burning power plants, with CaO contents between about 10 and 50 weight %, have been proven to have a high mineral …
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Tested Calcareous fly ashes (W) from Bełchatów power plant demonstrates high sieve residue (0.045 mm) what results in significant water demand and problems with concrete …
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calcium fly ash can be utilised to manufacture approximately 2.5 cubic meters of high quality fly ash- based geopolymer concrete, and hence earn monetary benefits through carbon-credit trade.
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The high-calcium fly ashes (HCFA) of Krasnoyarsk TPP-2, Russia were studied. The HCFA were selected from each of the 4 fields of the electrostatic precipitator. It was determined that the size distribution, chemical and quantitative phase composition ... The fine high-calcium fly ash as the basis of composite cementing material. Olga Sharonova ...
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The fundamental requirements of high ... (Corresponding author phone: +60175230982; email: engrfam@gmail) ... Characteristics of Low-Calcium Fly ash-based
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Herein the high calcium lignite fly ash with calcium oxide constituent in a range of 20%-30% is the focus of this study. Important characteristics of fly ash have been studied, including physical ...
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Conclusion This research investigates the effects of calcium formate (CF) on PC, high volume fly ash (HVFA) pastes with 60% and 70% fly ash. The optimal dosage of CF for PC, 60%HVFA and 70%HVFA pastes respectively to reach the highest strength was found.
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In terms of calcium source regulation, many studies have found that the improvements of calcium source to low-calcium fly ash geopolymers was mainly due to the formation of C-S-H gel, which can accelerate the hardening process [27], [28], and also improve the mechanical properties of alkali-activated low-calcium fly ash geopolymers [28], [29 ...
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High-calcium fly ash with median particle size of 21.26 μm was replaced by waste glass powder at the levels of 10%, 20%, 30%, and 40% by weight to produce the geopolymer pastes. The waste glass powders consisted of ground fluorescent lamp glass and ground container glass with median particle sizes of 4.65 and 11.72 μm, respectively.
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Table 6 has shown that mullite, an essential mineral in low calcium fly ash, is not available in three ashes investigated in this study. Anhydrite content in three ashes is considerably high, more than 2 wt%, which is less than 0.34 wt%, in …
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showe d that t he workabilit y of high calcium fly ash geopolym er mortars m ade with crumb ru bber . was lower t han that of the mortar co ntaining only ri ver sand. The 7-d ay compress ive ...
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Two types of fly ash are commonly used in concrete: Class C and Class F. Class C are often high-calcium fly ashes with carbon content less than 2%; whereas, Class F are generally low-calcium fly ashes with carbon …
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High range water reducing naphthalene based superplasticizer at 2.5 % by mass of fly ash was added in order to improve the workability. The mixture proportions are shown in Table 3.
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Class C fly ash was obtained from Neyveli Lignite Corporation, having specific gravity 2.1 and specific surface 319 kg/m 2 used. The chemical compositions of the fly ash are shown in Table 1. To activate the fly ash, commercial grade sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3) alkaline solution was used as alkaline activator ...
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High-calcium fly ash contains free CaO, CaSO 4, 3CaO·Al 2 O 3, which all can react with water. In addition, a significant part of the HCFA represents glass phase that is capable of hydration in ...
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High-calcium fly ash (HCFA) from the lignite PCC process of the Mae Moh power plant complied with Class C coal ash specifications and was used for comparison. The minimum combined content of SiO 2, Al 2 O 3, and Fe 2 O 3 of 50% was detected for the Class C fly ash, with a high calcium content of 31.0 wt%. The median particle size (D50) of the ...
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Mohammed et al. [11] reported a compressive strength of 50 MPa with excellent flowability for OPGs synthesised with high calcium fly ash and anhydrous-Na 2 SiO 3. Nonetheless, the pore content and the effect of water content in the one-part mixtures are not studied. The porosity of the OPG structure is essential to support the mechanical ...
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High calcium fly ash addition of at 25% reduced the swelling potential by 65%.
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The combination of factors was established for using high-calcium fly ash (HCFA) as a binder material of high early and long-term strength: (1) high dispersity of microspherical HCFA, 90% <10 μm; (2) the positive effect of polycarboxylate superplasticizer, that allowed to use water / binder = 0.25; (3) formation of finely mixed hydrate phases such as portlandite, …
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The database included only high calcium fly ash concrete mixes and did not consider mortar or phase mixes, and excluded the blended high calcium fly ash composites. This selection criteria was adopted to develop a mix design procedure that could predict the standard 28-day compressive strength for high calcium fly ash geopolymer concrete ...
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The goal of this investigation is to study dry and moist carbonation of a high calcium fly ash. The process is maintained at 3 different temperatures: 160, 220 and 290 ⁰C and at pressure range of CO 2 and water vapor from 1 to 6 bars. The accelerating effects of …
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Autogenous shrinkage of fine-grained concrete depending on percentage of cement replacement with fly ash: 0D 0 is 0%; 10D 0 is 10%; 20D 0 is 20% and on Ca(NO 3 ) 2 content in expansive agent at 10 ...
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THE HYDRAULIC ACTIVITY OF HIGH CALCIUM FLY ASH Fig. 2 XRD pattern of the high calcium fly ash Table 3 Chemical composition of high calcium fly ash in particular sections of electrofilter Component Content/mass% section I section II section III SiO 2 57.8/82.0 34.8/44.5 30.4/33.3 Al 2O 3 1.5/2.6 3.7/5.1 4.4 Fe 2O 3 2.3/6.4 4.2/7.1 4.7/6.6 TiO 2 ...
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The two cementitious systems are clay–portland cement and clay-high calcium fly ash (FA) geopolymer. The 28-day strength of the clay-FA geopolymer is up to 1.2 times higher than that of clay-cement. The results show that the physical performance of clay-FA geopolymer when exposed to sulfate solution is better than that of clay-cement ...
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