Iron ore sintering is the first high-temperature process in the iron and steel industry. The annual sinter output of China has exceeded one billion tons [20].The iron ore sintering process used to treat waste incineration fly ash mainly has the following advantages: (i) Waste incineration fly ash contains a large amount of CaO, which can be used as calcium based flux …
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The fine high-calcium fly ash (d90 < 10 microns) selected from the fourth field of electrostatic precipitator was the source for high strength specimens. In the composition with a superplasticizer ...
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High calcium fly ash was found to be much less effective in resisting deterioration than control samples containing general use portland cement. Part of the experimental program focused on adding calcium sulfate or silica fume to high-calcium fly ash to enhance its
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The high-calcium fly ash (HCFA) was used as the primary source material to produce the geopolymer concrete; therefore, it can set and harden at ambient temperature. Bentonite was used as a partial replacement (0%, 10%, 15%, and 20%) for fly ash in both the GNAC and GRAC.
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In the experiment, 0–40% auto glass powder (AGP) by weight was used as a substitute for high-calcium fly ash in the geopolymer paste. The setting time, workability, …
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14 Phone : + 33 2 40 84 58 02 15 Fax: + 33 2 40 58 57 77 16 E-mail: [email protected] 17 Abstract 18 This study addresses the use of alkali activated high-calcium fly ash-based binder to 19 improve engineering characteristics of soft clay-rich soils as an alternative to common ... 110 high-calcium fly ash only, whereas KF50 and KF20 ...
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The setting time of concrete should be sufficient enough for concrete to be handled and casted before any sign of setting. The low-calcium class-F fly ash-based geopolymer has a high setting time, which can be reduced significantly by using heat curing [25,41] or by adding GGBFS [25,29]. Evaluating the parameters that influence the setting ...
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According to ECOBA statistics, the amount of High Calcium Fly Ashes (HCFA) in Europe is more than 50% of the total fly ash produced by burning hard coal and lignite [2].
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To utilize discarded shield residue and alleviate the shortage of subgrade filling, industrial wastes such as calcium carbide slag (CCS) and fly ash (FA) were considered to enhance the mechanical properties of the shield residue. A series of laboratory tests, including California Bearing Ratio (CBR) tests, unconfined compressive strength (UCS) tests, moisture …
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For variations of substitution materials, fly ash is used as a cement substitution.The variation of fly ash is 20% and while the limestone waste is used variations of 0%, 10%, 20%, 30% and 40%.The ...
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Keywords: High-calcium fly ash; Concrete; Compressive strength; Fly ash treatment 1. Introduction Fly ash is used extensively in concrete either as a separately batched material characterized as addition as it appears in EN 206-1 [1] or as an ingredient in blended cement (Type CEM II, IV of EN 197-1) [2].
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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 fly ash. Theoretically, high-calcium fly ash produced from the combustion of subbituminous or lignite coal has cementing or self-hardening properties [24].
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Class C Fly Ash is derived from burning younger, softer coal, such as lignite or sub-bituminous coal. It contains higher amounts of calcium, in addition to silica, alumina, and …
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Low cost and sustainable repair material made from alkali-activated high-calcium fly ash with calcium carbide residue. Constr. Build. Mater., 247 (2020), Article 118543, 10.1016/j.conbuildmat.2020.118543. View PDF View article View in Scopus Google Scholar [69]
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Kalinkin et al. [27] prepared a fly ash-based geopolymer blended with dolomite, and concluded that adding an appropriate amount of dolomite can improve the strength of fly ash-based geopolymer due to its high calcium content. The aforementioned studies reveal that adding an appropriate amount of external calcium source is capable of effectively ...
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109 high-calcium fly ash only, whereas KF50 and KF20 are the alkali activated soils. KF50 110 corresponding to a solid phase made of 50% of high-calcium fly ash and 50% of kaolin 111 in mass, and KF20 corresponding to a solid phase made of 20% of high-calcium fly ash 112 and 80% of kaolin. List of samples is summarized up in Table 2.
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The use of high-calcium fly ash from the combustion of Kansk-Achinsk coal in the production of autoclaved and non-autoclaved aerated concrete, in addition to saving cement, leads to a decrease in shrinkage and an increase in the strength of products [12].The high-volume fly ash concretes where 50–70 % PC was substituted, are of great interest ...
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relatively high amount of calcium oxide (Class C fly ash). For concrete containing 20% fly ash, with the addition of lime, a decrease in porosity was observed by Mira, Papadakis and Tsimas (2002). ...
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This paper investigates the hydrated phase assemblage, microstructure, and gel composition of sodium hydroxide (NaOH)-activated fly ash–slag blends with either low-calcium or high-calcium fly ash. The results show that the nature of precipitated calcium–aluminosilicate–hydrate (C-A-S-H) and alkali aluminosilicate-hydrate (N-A-S-H) …
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Influences of the Ratios of High-Calcium Fly Ash to Low-Calcium Fly Ash on the Strength and Drying Shrinkage of Geopolymer Mortar. May 2014; Advanced Materials Research 931-932:416-420;
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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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All geopolymer mortars were made with sand to fly ash ratio of 2.75. The NaOH of three concentrations viz., 10, 15 and 20 M and the sodium silicate to NaOH ratios by mass of 0.67, 1.00, 1.50, and 3.00 were used.In order to obtain the workable geopolymer mortar, a minimum base water content of 5% by mass of the geopolymer paste (fly ash, NaOH, sodium silicate …
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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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This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% …
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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 …
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much fly ash to use in a specific concrete application. 1. ... high levels of fly ash substitution (typically more than 30%) can sometimes lead to issues such as reduced early-age strength, ... It has a lower calcium content compared to Class C fly ash. Properties:• Primarily pozzolanic, meaning it requires a source of calcium, such as ...
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A critical review on mechanochemical processing of fly ash and fly ash-derived materials Sci. Total Environ., 860 ( 2023 ), Article 160529 View PDF View article View in Scopus Google Scholar
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Fly ash is an aluminosilicate material that is widely used for the preparation of geopolymer composites, especially low-calcium fly ash (LCF) (Nath and Sarker, 2017).In fact, one of the most important benefits of using fly ash for geopolymer synthesis is its easy availability compared to other source materials (Mehta and Siddique, 2017).In Thailand, most fly ash is …
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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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2.1.1. High-Calcium Fly Ash (HCFA) Fly ash (FA) used in this study was obtained locally from YTL Cement Bhd Malaysia. The oxide analysis of the FA determined by X-ray fluorescence (XRF) analysis is shown in Table 1.The pozzolanic compounds level of the FA used in this study (SiO 2 + Al 2 O 3 + Fe 2 O 3) is 61.9% and can therefore be classified as Class C fly ash according to …
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