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Journal articles on the topic 'Class F fly ashes'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Latifee, Enamur R. "State-of-the-Art Report on Alkali Silica Reactivity Mitigation Effectiveness Using Different Types of Fly Ashes." Journal of Materials 2016 (September 27, 2016): 1–7. http://dx.doi.org/10.1155/2016/7871206.

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Use of fly ash by percent replacement of cement is considered as one of the most economical and effective methods for mitigating alkali-silica reaction (ASR) related distress in the concrete. However, fly ash has been proven to be somewhat variable in its effectiveness in inhibiting alkali-silica reactivity, principally because its composition depends on the coal properties from which it is derived. Typically class C fly ashes are not as efficient as class F ashes due to their higher calcium oxide content. Nevertheless, it is important to find out whether the lime content in the fly ash has linear effect on ASR distress mitigation and if the dosage of fly ash is more influential than type of fly ash. This research conducted extensive testing with nine different types of fly ashes with three in each category of fly ashes, class C, class F, and intermediate class. The results indicated that the effect of increased dosage of fly ash on ASR mitigation is linear for both low-lime and high-lime fly ashes and the dosage effect is more significant with rapid effect with high-lime fly ashes compared to low-lime fly ashes.

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2

Acar, I., and M. U. Atalay. "Characterization of sintered class F fly ashes." Fuel 106 (April 2013): 195–203. http://dx.doi.org/10.1016/j.fuel.2012.10.057.

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3

Seyrek, Evren. "Engineering behavior of clay soils stabilized with class C and class F fly ashes." Science and Engineering of Composite Materials 25, no. 2 (March 28, 2018): 273–87. http://dx.doi.org/10.1515/secm-2016-0084.

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AbstractDamages and economical losses due to problematic soils have caused researchers to conduct many studies for the stabilization of these soils within years. Especially, the use of fly ashes in soil stabilization provides great benefits in contributing to the economy, as well as decreasing the environmental pollution. In the present study, the stabilization characteristics of soil-fly ash mixtures were evaluated in terms of Atterberg limits, compaction characteristics, swell potential and unconfined compressive strength with curing effect. To determine these effects, Catalagzi and Soma fly ashes obtained from Turkey were used in different proportions by weight for stabilization of clay soil samples. It was found that the plasticity index of the soils decreased considerably with the addition of fly ashes, while the strength improved and swell potential decreased. The decreasing trend in the swell percentage and swell pressure values decelerated especially after 25% fly ash additive content and negligible changes occurred. Similar behavior was observed in strength tests. Experimental results show that swelling and strength properties of the soils could be improved by using fly ash and Soma fly ash is far more effective than Catalagzi fly ash.

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4

Acar, Ilker, Thomas L. Robl, and M. Umit Atalay. "Separation of ultrafine particles from class F fly ashes." E3S Web of Conferences 8 (2016): 01051. http://dx.doi.org/10.1051/e3sconf/20160801051.

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5

Uysal, Mucteba, and Veysel Akyuncu. "Durability performance of concrete incorporating Class F and Class C fly ashes." Construction and Building Materials 34 (September 2012): 170–78. http://dx.doi.org/10.1016/j.conbuildmat.2012.02.075.

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6

Ruiz-Román, J. M., C. Alonso Santos, L. E. G. Cambronero, F. Corpas, M. Alfonso, and A. J. Moraño. "Aprovechamiento de las cenizas volantes, clase F, de centrales térmicas para la fabricación de materiales cerámicos." Boletín de la Sociedad Española de Cerámica y Vidrio 39, no. 3 (June 30, 2000): 229–31. http://dx.doi.org/10.3989/cyv.2000.v39.i3.831.

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7

Maltais, Y., J. Marchand, R. Gagné, and A. Tagnit-Hamou. "Effets des cendres volantes sur le développement des résistances mécaniques des bétons préfabriqués." Canadian Journal of Civil Engineering 23, no. 4 (August 1, 1996): 940–49. http://dx.doi.org/10.1139/l96-900.

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The results of an investigation of the influence of fly ashes on the development of mechanical properties of concretes subjected to 24-h thermal curing are presented in this paper. In addition to the curing temperature (23 and 60 °C), the variables studied in this investigation were the type of cement (types 10 and 30) and the source of fly ashes (four different North-American class F fly ashes). Overall, 10 different concrete mixtures were tested. Test results indicate that thermal curing tends to increase significantly the concrete compressive strength in the first 24 h. Data also demonstrate that the thermal curing regime does not have any detrimental effect on the long-term compressive strength of ordinary portland cement concrete. Compressive strength of fly ash concretes was significantly reduced by thermal curing in the 1- to 28-day period, despite an initial increase. The influence of thermal curing on the development of concrete compressive strength is discussed. Key words: compressive strength, steam curing, fly ashes, precast concrete.

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8

Ekaputri, Januarti Jaya, Muhammad Bahrul Ulum, Triwulan, Ridho Bayuaji, Tri Eddy Susanto, and Mohd Mustafa Al Bakri Abdullah. "A Comprehensive Characterization and Determination of Fly Ashes in Indonesia Using Different Methods." Applied Mechanics and Materials 754-755 (April 2015): 320–25. http://dx.doi.org/10.4028/www.scientific.net/amm.754-755.320.

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This paper presents an observation on fly ash quality in East Jawa, Indonesia. The ash samples were collected from 16 fly ashes produced by some Indonesian power plants. The samples are majority categorized as class F fly ashes with good pozzolanic characteristics according to the standard. The samples were examined for their physical, chemical and mechanical properties with compression test. The test was conducted by making some mortars and paste containing fly ash as cement replacement in accordance with three methods. The compressive strength results were compared with the control specimens made from ordinary Portland cement to obtain a strength activity index (SAI). The results showed that physical properties of fly ash influenced the mechanical properties of mortars more than those showed by chemical characterization.

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9

Zahid, Muhammad, Nasir Shafiq, Mohd Fadhil Nuruddin, Ehsan Nikbakht, and Asif Jalal. "Effect of Partial Replacement of Fly Ash by Metakaolin on Strength Development of Fly Ash Based Geopolymer Mortar." Key Engineering Materials 744 (July 2017): 131–35. http://dx.doi.org/10.4028/www.scientific.net/kem.744.131.

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This article aims to investigate the compressive strength variation by the addition of metakaolin as a substitute of fly ash in the fly ash based geopolymer mortar. Five, ten and fifteen percent by weight of fly ash was replaced by highly reactive metakaolin. Two type of fly ashes namely, ASTM class F and ASTM class C were used as a base material for the synthesis of geopolymer mortar. Eight molar sodium hydroxide solution mixed with sodium silicate solution was used as alkaline activator. For optimum geopolymerization, mortar was cured at sixty degree Celsius for twenty four hours duration. Results show different behavior of metakaolin replacement on compressive strength for two different types of fly ash based geopolymer mortar. Improvement in compressive strength was seen by addition of metakaolin in ASTM class F fly ash based geopolymer. On the other hand compressive strength was decreased abruptly in fly ash class C based geopolymer up to certain replacement level.

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10

Palmer, B. "Liners for waste containment constructed with class F and C fly ashes." Journal of Hazardous Materials 76, no. 2-3 (September 15, 2000): 193–216. http://dx.doi.org/10.1016/s0304-3894(00)00199-0.

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11

Oh, Jae Eun, Yubin Jun, and Yeonung Jeong. "Characterization of geopolymers from compositionally and physically different Class F fly ashes." Cement and Concrete Composites 50 (July 2014): 16–26. http://dx.doi.org/10.1016/j.cemconcomp.2013.10.019.

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12

Rangaraju, Prasada Rao, and Ketan R. Sompura. "Influence of Cement Composition on Expansions Observed in Standard and Modified ASTM C1260 Test Procedures." Transportation Research Record: Journal of the Transportation Research Board 1914, no. 1 (January 2005): 53–60. http://dx.doi.org/10.1177/0361198105191400107.

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This paper presents the results of a laboratory study conducted to determine the influence of cement composition on the expansions observed in standard and modified ASTM C1260 tests. Also, the effectiveness of selected mitigation measures for alkali—silica reactivity was studied by using a modified ASTM C1260 test. Two different cements with substantially different alkali levels were used in combination with a Class F fly ash and a Class C fly ash. The results obtained from tests with 89 different sources of fine aggregate were analyzed. The results from this study indicate that cement composition has a distinct influence on the expansion levels observed in the ASTM C1260 study. For a majority of the aggregates tested in this study (88%), the use of a specific cement low in alkali content resulted in higher expansion than a cement with a relatively higher alkali content, regardless of the level of reactivity of the aggregate in the standard ASTM C1260 tests. Class F fly ash was found to be more effective than Class C fly ash in reducing the expansions in the modified ASTM C1260 tests. However, the cement used in the mixture influenced the percent reduction in expansion offered by both Class F fly ash and Class C fly ash. The use of low-alkali cement with Class F and Class C fly ashes yielded larger reductions in percent expansion.

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13

Temuujin, J., J. Mapiravana, U. Bayarzul, G. Oyun-Erdene, Ts Zolzaya, B. Darkhijav, M. Dlamini, and C. H. Rüscher. "Comparative Studies of Alkali Activated South African Class F and Mongolian Class C Fly Ashes." Waste and Biomass Valorization 9, no. 6 (March 9, 2017): 1047–60. http://dx.doi.org/10.1007/s12649-017-9881-5.

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14

Sumer, Mansur. "Compressive strength and sulfate resistance properties of concretes containing Class F and Class C fly ashes." Construction and Building Materials 34 (September 2012): 531–36. http://dx.doi.org/10.1016/j.conbuildmat.2012.02.023.

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15

Sivapullaiah, P., and Arif Moghal. "CBR and strength behavior of class F fly ashes stabilized with lime and gypsum." International Journal of Geotechnical Engineering 5, no. 2 (April 2011): 121–30. http://dx.doi.org/10.3328/ijge.2011.05.02.121-130.

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16

Jun, Yubin, and Jae Eun Oh. "Mechanical and microstructural dissimilarities in alkali-activation for six Class F Korean fly ashes." Construction and Building Materials 52 (February 2014): 396–403. http://dx.doi.org/10.1016/j.conbuildmat.2013.11.058.

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17

Saylak, Don, Surendra K. Mishra, Gleb G. Mejeoumov, and Chang-Seon Shon. "Fly Ash-Calcium Chloride Stabilization in Road Construction." Transportation Research Record: Journal of the Transportation Research Board 2053, no. 1 (January 2008): 23–29. http://dx.doi.org/10.3141/2053-04.

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Both fly ash and calcium chloride have been used in a wide variety of roadway construction applications. Engineering applications of both Class C and Class F fly ashes include portland cement concrete, soil and road base stabilization, flowable fills, grouts, structural fills, and asphalt filler. Until recently, the primary roadway application for calcium chloride has been as a dust-controlling agent on unsurfaced roads. Ongoing research at Texas A&M and Texas Transportation Institute has concluded that when the two are strategically combined within a roadway mix design, their individual mineralogical and physicochemical characteristics interact to further enhance the service performance of the roadway. Although the fines content in the roadbed composition is critical, there is a synergistic effect on the strength generated when calcium chloride is added along with fly ash. This synergistic blending of fly ash and calcium chloride is referred to as “surface-activated stabilization.’'

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18

Ma, Weiping, Paul W. Brown, and Sridhar Komarneni. "Characterization and cation exchange properties of zeolite synthesized from fly ashes." Journal of Materials Research 13, no. 1 (January 1998): 3–7. http://dx.doi.org/10.1557/jmr.1998.0001.

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Zeolite P was formed from class F fly ash under hydrothermal conditions. The fly ash was reacted with 2.8 or 5 M NaOH at 100 °C. Zeolite of the above type was produced regardless of the NaOH concentration or the addition of quartz, thus indicating its formation over a wide range of conditions. The zeolite produced was of the NaP-type with a fibrous morphology. Analysis of the pore structure of this zeolite by the BET method indicates a type II isotherm. The specific surface areas of synthesized zeolites increased from 28.5 to 41.1 m2/g when the NaOH concentration was increased from 2.8 to 5.0 M. This zeolite showed a significant selectivity for the uptake of Cs and Sr. Cs uptake ranged from 7.67 to 8.61 meq/100 g while that of Sr ranged from 9.8 to 10.54 meq/100 g. The value obtained depended on the specific synthesis conditions. These values are higher than those observed for tobermorite prepared from the same fly ash even though the tobermorite exhibited a higher specific surface area.

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19

Winburn, Ryan S., Dean G. Grier, Gregory J. McCarthy, and Renee B. Peterson. "Rietveld quantitative X-ray diffraction analysis of NIST fly ash standard reference materials." Powder Diffraction 15, no. 3 (September 2000): 163–72. http://dx.doi.org/10.1017/s0885715600011015.

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Rietveld quantitative X-ray diffraction analysis of the fly ash Standard Reference Materials (SRMs) issued by the National Institute of Standards and Technologies was performed. A rutile (TiO2) internal standard was used to enable quantitation of the glass content, which ranged from 65% to 78% by weight. TheGSASRietveld code was employed. Precision was obtained by performing six replicates of an analysis, and accuracy was estimated using mixtures of fly ash crystalline phases and an amorphous phase. The three low-calcium (ASTM Class F) fly ashes (SRM 1633b, 2689 and 2690) contained four crystalline phases: quartz, mullite, hematite, and magnetite. SRM 1633b also contained a detectable level of gypsum, which is not common for this type of fly ash. The high-calcium (ASTM Class C) fly ash, SRM 2691, had eleven crystalline phases and presented a challenge for the version ofGSASemployed, which permits refinement of only nine crystalline phases. A method of analyzing different groups of nine phases and averaging the results was developed, and tested satisfactorily with an eleven-phase simulated fly ash. The results were compared to reference intensity ratio method semiquantitative analyses reported for most of these SRMs a decade ago.

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20

Charoenchai, Ridtirud, and Prinya Chindaprasirt. "Influences of the Ratios of High-Calcium Fly Ash to Low-Calcium Fly Ash on the Strength and Drying Shrinkage of Geopolymer Mortar." Advanced Materials Research 931-932 (May 2014): 416–20. http://dx.doi.org/10.4028/www.scientific.net/amr.931-932.416.

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New types of binders are being developed as an alternative to traditional cement. These alternatives are developed to have better properties and to be more environmentally friendly. Geopolymer is a novel binder that is produced from by-products such as fly ash, rich hushes ash and bio mass ash. In this experiment, fly ash, which was a by-product from electrical-generating power plants, was used during the synthesis of geopolymer. According to ASTM standard C168, fly ash is categorized into two types: class F and class C. This research focuses on the effects of using both types of fly ashes on mechanical properties of geopolymer. The experiment studies the changes on setting time, drying shrinkage and compressive strength of geopolymer mortar when 0, 25, 50, 75 and 100 percent of total weight of class F fly ash (LCF) is substituted with class C counterpart (HCF). The study used sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) as alkali activators. The samples were cured for 24 hours either at an ambient temperature of 25°C or at an elevated temperature of 60°C.The result showed that the setting time of pure LCF geopolymer mortar was 6 times longer than that of the pure HCF ones. In addition to setting time, the specimens with 25 percent of their total binders weight replaced by HCF appeared to have the highest strength. However, the increase in HCF also increased the drying shrinkage by 6 and 12times when the specimens were cured at25°C and at 60°C respectively

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21

Wardhono, A. "Comparison Study of Class F and Class C Fly Ashes as Cement Replacement Material on Strength Development of Non-Cement Mortar." IOP Conference Series: Materials Science and Engineering 288 (January 2018): 012019. http://dx.doi.org/10.1088/1757-899x/288/1/012019.

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22

Wagner, Seth, Gabrielle Wickizer, Douglas Cleary, Gilson R. Lomboy, Danielle Kennedy, Benjamin Watts, and Peter Bly. "Use of Coarse Recycled Concrete Aggregate in Ternary Blended Portland Cement Concrete." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 10 (July 30, 2020): 705–14. http://dx.doi.org/10.1177/0361198120935876.

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The purposes of this study were to (a) investigate concrete pavement mixtures with recycled concrete aggregates using ternary blended cementitious binders, (b) measure the fresh and hardened properties of the concrete mixtures, and (c) assess the durability of concrete implementing the use of recycled coarse aggregates with ternary binders. Mixtures had recycled concrete aggregates at varying replacement rates. The binders were combinations of Portland cement, Class C and F fly ashes, and ground granulated blast furnace slag. At 50% replacement of virgin aggregates, some specimens showed comparable mechanical performance to the control mix. Performance is heavily tied to quality of recycled aggregates. The combined use of fly ash and blast furnace slag showed improvements in results for drying shrinkage, freeze–thaw durability, resistivity, and alkali–silica reaction mitigation.

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23

Gandham, S., R. K. Seals, and Paul T. Foxworthy. "Phosphogypsum as a Component of Flowable Fill." Transportation Research Record: Journal of the Transportation Research Board 1546, no. 1 (January 1996): 79–87. http://dx.doi.org/10.1177/0361198196154600109.

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Phosphogypsum (PG) is a by-product of the production of phosphoric acid, a key ingredient in the manufacture of fertilizers. Large amounts of PG have been stockpiled in Florida, Louisiana, and Texas, as well as other parts of the world. The means of using and disposing of this by-product with minimal environmental impact have been developed in research spanning almost 20 years. A study was conducted to investigate PG as a potential component of flowable fill materials along with Class C fly ash. Both Class F and Class C fly ashes have been used successfully to provide flowability and strength characteristics to flowable fill. A number of mix proportions of PG and fly ash were tested for flowability, time of setting, and unconfined compressive strength in a preliminary test series. Using the results of these preliminary tests, three final design mixtures were developed. These mixtures were then subjected to different physical and engineering property tests, including flowability, time of setting, unconfined compressive strength, flexural strength, dimensional stability, and permeability. Tests were also conducted to evaluate the environmental effects of the individual mixtures. These tests included the toxicity characteristic leaching procedure and radon emission testing. The results of this study indicated that PG can be used successfully as a component of flowable fill.

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24

EISELE, T. C., S. K. KAWATRA, and A. NOFAL. "COMPARISON OF CLASS C AND CLASS F FLY-ASHES AS FOUNDARY SAND BINDERS AND THE EFFECTIVENESS OF ACCELERATORS IN REDUCING CURING TIME." Mineral Processing and Extractive Metallurgy Review 25, no. 4 (October 2004): 269–78. http://dx.doi.org/10.1080/08827500390256816.

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25

Izidoro, Juliana De Carvalho, Caio Miranda, Davi Castanho, Carlos Rossati, Felipe Campello, Sabine Guilhen, Denise Fungaro, and Shaobin Wang. "Physical and chemical characteristics of feed coal and its by-products from a Brazilian thermoelectric power plant." Journal of Applied Materials and Technology 1, no. 1 (July 14, 2019): 1–14. http://dx.doi.org/10.31258/jamt.1.1.1-14.

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In this study, feed coal (FC) from the Figueira Thermoelectric Power Plant (FTPP), located in the state of Paraná (PR), Brazil was characterized by X-ray fluorescence (XRF), X-ray diffractometry (XRD), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), particle size distribution analysis by laser diffraction, loss of ignition (LOI), total carbon content (TC), pH and conductivity. FC-derived by-products (CCBs) collected at the FTPP were: bottom ash (BA), fly ash from cyclone filter (CA) and fly ash from bag filter (FA). In addition to the techniques used for feed coal characterization, CCBs were also characterized by total surface area (by using BET method), external surface area (by using laser diffraction), cation exchange capacity (CEC), bulk density, besides leaching and solubilization tests. FC sample contains 72.2% of volatile material, of which 55.3% is total carbon content. LOI, FTIR, TGA and TC analyzes corroborated with these results. The main crystalline phases in the FC sample were found to be quartz, kaolinite and pyrite. The elements As, Cr, Ni and Pb were encountered in the FC sample, indicating that the use of FTPP feed coal should be monitored due to the toxic potential of these elements. The three coal ashes were classified as class F according to ASTM and presented similar chemical composition, with total content of the main oxides (SiO2, Al2O3 and Fe2O3) above 72%. Ashes enrichment factor analysis (EF) showed that As, Zn and Pb concentrate mainly in fly ash from bag filter (FA), whereas the elements K and Mg presented higher enrichment in the bottom ash (BA) . All ashes presented quartz, mullite and magnetite as crystalline phases, as well as the same functional groups, related to the presence of humidity, organic matter and Si and Al compounds. XRD, XRF, TGA, FTIR, LOI and TC techniques were correlated and confirmed the obtained results. Total and external surface area values of CCBs were related to the total carbon content (TC), as well as to the results of particle size distribution and the scanning electron micrographs of the samples. On the other hand the CEC of the ashes showed relation with the particle size distribution and with the external surface area. Leaching and solubilization tests of CCBs showed that FA sample was considered hazardous and classified as class I waste, while CA and BA samples were considered non-hazardous and non-inert wastes and classified as class II-A. FA sample from Figueira power plant must be discarded only after treatment or a stringent disposal criterion must be followed to avoid contamination on site. In this work, feed coal sample was also compared to the CCBs samples generated from it. The results showed the differences between fuel and products through the different characterization techniques. In addition to contributing to the understanding of the relationship between coal and its combustion products, this work can also help to reduce the environmental impacts caused by the CCBs disposal, as well as can also be used to compare the characteristics of CCBs from FTPP with the new wastes that will be generated by the same thermal power plant that will be soon modernized.

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26

Manoharan, V., I. A. M. Yunusa, P. Loganathan, R. Lawrie, C. G. Skilbeck, M. D. Burchett, B. R. Murray, and D. Eamus. "Assessments of Class F fly ashes for amelioration of soil acidity and their influence on growth and uptake of Mo and Se by canola." Fuel 89, no. 11 (November 2010): 3498–504. http://dx.doi.org/10.1016/j.fuel.2010.06.028.

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27

Jun, Yubin, and Jae Eun Oh. "Microstructural characterization of alkali-activation of six Korean Class F fly ashes with different geopolymeric reactivity and their zeolitic precursors with various mixture designs." KSCE Journal of Civil Engineering 19, no. 6 (January 21, 2015): 1775–86. http://dx.doi.org/10.1007/s12205-015-0132-7.

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28

Bhat, S. T., and C. W. Lovell. "Design of Flowable Fill: Waste Foundry Sand as a Fine Aggregate." Transportation Research Record: Journal of the Transportation Research Board 1546, no. 1 (January 1996): 70–78. http://dx.doi.org/10.1177/0361198196154600108.

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Flowable fill is generally a mixture of sand, fly ash, a small amount of cement, and water. Sand is the major component of most flowable fill mixes; consequently, using a waste material as a substitute for natural sand results in the beneficial use of the waste material. Waste foundry sand (WFS) was used as a fine aggregate in this study. Three green sands from ferrous foundries and two Class F fly ashes were used. A natural river sand was used for comparison. The flow behavior, hardening characteristics, and ultimate strength behavior of flowable fill were investigated. The penetration resistance necessary to sustain walkability as the fresh flowable fill hardens was determined, and the time necessary to achieve this penetration resistance was defined as “walkable time.” The unconfined compressive strength at 28 days appeared to correlate well with the water-to-cement ratio. The 90-day compressive strength test results indicate that a maximum rise of 25 to 30 percent in long-term strength with respect to 28-day strength can be expected. The permeability of hardened flowable fill was found to be low (around 10−6cm/sec). The pH of pore solution of hardened flowable fill indicated that the potential for corrosivity is low. The toxicity tests indicated that some WFSs are environmentally safe. The concepts explained are not necessarily restricted to flowable fill containing WFS; they can be generalized as being applicable to all flowable fills.

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29

Wei, Qiang, and Weijiao Song. "Mineralogical and Chemical Characteristics of Coal Ashes from Two High-Sulfur Coal-Fired Power Plants in Wuhai, Inner Mongolia, China." Minerals 10, no. 4 (April 4, 2020): 323. http://dx.doi.org/10.3390/min10040323.

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The mineralogical and chemical characteristics of the feed coals and coal combustion products (CCPs) from two power plants (Xilaifeng and Damo) that consume coals from the Wuda Coalfield, Inner Mongolia, were investigated, using XRD, SEM–EDS, XRF, and ICP-MS. The feed coals from Xilaifeng and Damo are both of high ash yield (52.93% and 48.36%, respectively), and medium and high total sulfur content (2.22% and 3.32%, respectively). The minerals in the feed coals are primarily composed of kaolinite, quartz, illite, pyrite, and, to a lesser extent, gypsum and anatase. In addition to the elevated incompatible elements (Nb, Ta, Zr, Hf and Th), Li and Hg are enriched in the feed coals from the Xilaifeng and Damo power plants, respectively. Rare earth elements and yttrium (REY) are more enriched in the feed coals from Xilaifeng (194 μg/g) than those of Damo (93.9 μg/g). The inorganic phases of CCPs from both power plants are mainly composed of amorphous phase, quartz, hematite, illite, and anhydrite. Compared with the feed coals, concentrations of most trace elements in the CCPs are elevated, and they are preferentially enriched in the fly ashes relative to the bottom ashes (*f/b > 1), especially F, As, Sr, Mo, Se, and Hg (*f/b > 2.5). Furthermore, most trace elements (Xilaifeng: excluding Li, Cr, Co, Ni, Rb, Nb and Cs; Damo: excluding Li, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Cs and Ba) are more enriched in the (fine) fly ashes relative to the laboratory high-temperature coal ashes (HTAs). The REY barely differentiate in either the fly ash or bottom ash from Xilaifeng. In contrast, the REY in the fine and coarse fly ashes from Damo have very similar H-type distribution patterns with negative Ce and slightly positive Y anomalies. Attention should be paid to the enriched toxic elements (including F, As and Hg) in the fly ashes from both power plants due to possible adverse environmental effect.

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30

Janowska-Renkas, Elżbieta, and Jolanta Kowalska. "Use of fly ash from fluidized bed boilers in clinker-slag-ash based binders." MATEC Web of Conferences 174 (2018): 02002. http://dx.doi.org/10.1051/matecconf/201817402002.

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The study presents the state of knowledge regarding physical and chemical properties, as well as trends for application of fly ashes from combustion in fluidized bed boilers in building materials. Clinker - slag - ash based binders were tested that contained up to 40 mass % of fly ashes from combustion in fluidized bed boilers. It was demonstrated that fluidized bed combustion fly ashes (FBC fly ash), apart from granular blast furnace slag, could be the ingredient of low clinker Portland cements (ca. 20% by mass). These cements, compared to CEM I Portland cement, have higher water demand and durability in the corrosive environment, and a lower compressive strength value. Based on test results of binders with various content of blast furnace slag and fly ash, the clinker - slag - ash based binder was singled out, which demonstrated the higher durability in the corrosive environment. It was found that production of clinker - slag - ash based binders was possible in the strength class 32.5 even with 30% by mass of FBC fly ash content.

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31

Biernacki, Joseph J., Anil K. Vazrala, and H. Wayne Leimer. "Sintering of a class F fly ash." Fuel 87, no. 6 (May 2008): 782–92. http://dx.doi.org/10.1016/j.fuel.2007.08.024.

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Yildirim, Hasan, Mansur Sümer, Veysel Akyüncü, and Emrah Gürbüz. "Comparison on efficiency factors of F and C types of fly ashes." Construction and Building Materials 25, no. 6 (June 2011): 2939–47. http://dx.doi.org/10.1016/j.conbuildmat.2010.12.009.

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Çokça, Erdal. "Use of Class C Fly Ashes for the Stabilizationof an Expansive Soil." Journal of Geotechnical and Geoenvironmental Engineering 127, no. 7 (July 2001): 568–73. http://dx.doi.org/10.1061/(asce)1090-0241(2001)127:7(568).

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34

Vodová, Lucie, and Radomír Sokolař. "Behavior of Class C Fly Ash during Firing at High Temperatures." Advanced Materials Research 1000 (August 2014): 162–65. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.162.

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Fluidized fly ash (class C according to ASTM) from thermal power plants Hodonin and Ledvice and stoneware clay B1 were used in the experimental work dealing with SO2 emissions during the firing at 1200°C. The aim of the work was to define the temperature at which sulphur dioxide begins to leak, and the leakage rate of SO2. It was found that temperature of decomposition of anhydrite depends on particle size. For milled fly ash is this temperature 150°C lower than for unmilled ashes. The addition of clay also decreases the temperature of decomposition. Sulphur dioxide begins to leak at 975 °C for samples with 40% addition of fly ash.

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Strzałkowska, Ewa. "The composition of the organic and inorganic matter of the Siliceous fly ashes as part of their usefulness in technologies of building materials." Gospodarka Surowcami Mineralnymi 32, no. 1 (March 1, 2016): 71–88. http://dx.doi.org/10.1515/gospo-2016-0008.

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Abstract Nowadays in Poland around 18 mln tons of energy wastes are produced every year. The utilization method of wastes depends principally on their physicochemical properties. Siliceous fly ashes which have pozzolanic properties which advantageously influence on cement properties, are mainly used in production of cement. The results of studies of the phase composition of the different grain classes of the siliceous fly ash were presented in this article. The minerals: mullite and quartz as well as magnetite, hematite and calcite were identified on the base of thermal analysis, mikroscopic observation and X-ray diffractometry examination. Significant participation in the composition of investigated fly ashes have also fragments of unburned coal. They present different morphological forms depend on the porosity degree. The following forms were distinguished: cenospheres, networks, inertynite massive and porous, detritus. Porous particles accumulate mainly in the coarser grain class and are represented primarily by cenospheres and networks. Their content may have an adverse effect on any further applications of fly ash, so as it is necessary to separation of this class. This will reduce water demand and increase the freeze-thaw resistance of mortar and concrete containing fly ash.

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Misra, Anil. "Stabilization Characteristics of Clays Using Class C Fly Ash." Transportation Research Record: Journal of the Transportation Research Board 1611, no. 1 (January 1998): 46–54. http://dx.doi.org/10.3141/1611-06.

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Coal-burning utilities using subbituminous coal from Wyoming typically produce fly ash, which, because of its high calcium oxide content, may be classified as Class C fly ash. These ashes are characterized by their self-cementing property and therefore can be used for soil improvement. Stabilization characteristics of clay soils blended with Class C fly ash were evaluated. Because fly ash is a by-product, uniformity of its physical and chemical properties is significant for quality control. The statistical characteristics of fly ash physical and chemical properties are obtained and compared with the data in literature. Fly ash is blended with several different clay soils of varying plasticity to study moisture-density relationships and strength behavior of stabilized soils. It is observed that the fly ash used in these experiments has a rapid hydration characteristic. Consequently, higher densities and strengths are achieved when the compaction is performed with little or no delay after the addition of moisture to clay-fly ash blends. Conversely, delayed compaction produces low densities and strength. In addition, it is observed that the stabilization characteristics are closely related to the soil mineral type and plasticity. Results also are presented for strength gain behavior with curing period for the various soil-fly ash blends.

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Petersen, DR, RE Link, NS Pandian, and S. Balasubramonian. "Leaching Studies on ASTM Type F Fly Ashes by an Accelerated Process Method." Journal of Testing and Evaluation 28, no. 1 (2000): 44. http://dx.doi.org/10.1520/jte12073j.

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Barbosa, Rui, Diogo Dias, Nuno Lapa, and Benilde Mendes. "Using Biomass Ashes in Concretes Exposed to Salted Water and Freshwater: Mechanical and Chemical Properties." Advanced Materials Research 587 (November 2012): 16–20. http://dx.doi.org/10.4028/www.scientific.net/amr.587.16.

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The main aim of this work was to assess the possibility of using biomass ashes as substitutes for cement and natural aggregates in concretes without compromising their mechanical and chemical properties. Thirteen concrete formulations were prepared with different percentages of bottom and fly ashes produced at a forest biomass power plant. These formulations were submitted to mechanical compressive strength assays, after 28, 60 and 90 days of maturation. The reference formulation F1 that was produced without biomass ashes and one formulation incorporating fly and bottom ashes, F4, were selected for further characterization. After 90 days of maturation, the selected formulations were submitted to the leaching test described in the European Standard EN12457-2 (L/S ratio of 10 L/kg, in a batch extraction cycle of 24h) by using two different leaching agents: a synthetic marine medium (ASPM medium) and a synthetic freshwater medium (ISO 6341 medium). The eluates produced were submitted to chemical characterization which comprised a set of metals (As, Sb, Se, Cu, Zn, Ba, Hg, Cd, Mo, Pb, Ni, Cr, Cr VI, Al, Fe, Mg, Na, K and Ca), pH, SO42-, F-, dissolved organic carbon, chlorides, phenolic compounds and total dissolved solids. The substitution of 10% cement by fly ashes has not promoted the reduction of the compressive strength of concrete. The new formulation F4 has presented emission levels of chemical species similar or even lower to those observed for the reference formulation F1.

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Gangadhara Rao, M. V. B. B., P. K. Kolay, and D. N. Singh. "Thermal characteristics of a class F fly ash." Cement and Concrete Research 28, no. 6 (June 1998): 841–46. http://dx.doi.org/10.1016/s0008-8846(98)00054-4.

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Tkaczewska, Ewelina. "Influence of fly ashes with different glassy phase structure on properties of cement pastes and mortars." Budownictwo i Architektura 12, no. 4 (December 11, 2013): 029–40. http://dx.doi.org/10.35784/bud-arch.1956.

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Work analyzes relationship between fly ash pozzolanic activity and structure of its glass component. Model silica fly ashes are prepared by mixing synthetic glass, synthetic mullite and SiO2. Chemical composition of glasses was based on value of parameter ASI, defined as ratio of Al2O3/(Na2O+K2O+2CaO). Glass structure was built main by tetrahedra SiO4. In glass of parameter ASI<1, Al ions occur only in tetrahera AlO4, but in glass of parameter ASI>1, additionally in octahedra AlO6. It was found that glass containing in its structure Al ion in coordination 4 and 6 shows greater reactivity – more active Al2O3, higher pozzolanic indexes and positive effect on lime mortar strength. Cement with addition of ash containing glass of higher value of ASI has higher hydration heat and higher compressive strength. Using 20wt% of ashes it is possible to obtain cement CEM II/A-V, class 32.5R (Al ion in AlO4) or class 42.5N (Al ion in AlO4 and AlO6)

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Indraratna, B., P. Nutalaya, K. S. Koo, and N. Kuganenthira. "Engineering behaviour of a low carbon, pozzolanic fly ash and its potential as a construction fill." Canadian Geotechnical Journal 28, no. 4 (August 1, 1991): 542–55. http://dx.doi.org/10.1139/t91-070.

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Detailed laboratory investigations were conducted on Mae Moh fly ash from northern Thailand for the determination of its grain size distribution, mineralogy, pozzolanic activity, compaction and strength characteristics, and the collapse potential. On the basis of the experimental results, this fly ash is classified as ASTM class C, which is considered to be pozzolanic. It has good potential to be utilized as an effective fill for embankments (roads and dams), airfields, pavements, and building bricks, as well as for the stabilization of compressible or erodible foundations. Because of the fact that Mae Moh fly ash contains only a negligible amount of unburned carbon, its pozzolanic reactivity is accelerated, in comparison with the relatively inert, high-carbon fly ash produced elsewhere in Thailand and many other parts of Asia. It is also demonstrated that Mae Moh fly ash can be easily compacted to produce acceptable dry densities over a wide range of water contents. Curing with an adequate moisture supply in the presence of calcium oxide plays an important role in accelerating the pozzolanic reactions, hence improving the time-dependent-properties. This study further proposes that a curing period of 2–3 weeks is sufficient for this material to approach its maximum strength. Although the behaviour of one specific fly ash cannot generalize the wide array of other ashes, the test results obtained for Mae Moh fly ash may be applied to lignite ashes in the category of ASTM class C. Key words: fly ash, structural fill, compaction, compressive strength, shear strength, collapse potential, pozzolanic activity.

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Sokolář, Radomír, and Martin Nguyen. "Sulphur Dioxide Emissions during the Firing of Ceramic Bodies Based on Class C Fly Ash." Solid State Phenomena 296 (August 2019): 149–54. http://dx.doi.org/10.4028/www.scientific.net/ssp.296.149.

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Fluid fuel combustion technology in coal-fired power plants is very popular in the Czech Republic, resulting in a relatively high production of a specific by-product - fluidized fly ash (class C according to ASTM definition), which differs from the classical high-temperature fly ash in mineralogical composition with a high sulphur content of anhydrite CaSO4. Fluidized ash is not yet used in the production of fired building materials, where it could be used as a source of calcium oxide (for example, the production of porous ceramic tiles). However, high volume of sulphur dioxide emissions during the re-firing of fluidized fly ash in ceramic raw materials mixtures has been solved. The aim of the paper is definition of temperature ranges of anhydrite decomposition (formation of SO2 emission) from pure class C (fluidized) fly ashes from different sources (power plants) depending on granulometry of fly ash especially.

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Kim, Ann G., George Kazonich, and Michael Dahlberg. "Relative Solubility of Cations in Class F Fly Ash." Environmental Science & Technology 37, no. 19 (October 2003): 4507–11. http://dx.doi.org/10.1021/es0263691.

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Papayianni, Ionna, Fotini Kesikidou, and Stavroula Konopisi. "Alkali Activation of HCFA Mixtures with Aluminosilicate Additives - Mechanical Characteristics." Key Engineering Materials 761 (January 2018): 96–99. http://dx.doi.org/10.4028/www.scientific.net/kem.761.96.

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Over the last years, the increasing need of cost saving and environmental protection has led to finding alternative methods and materials in construction. One of these methods is the alkali-activation, which can transform alumino-silicate binders, like siliceous fly ashes, blast furnace slags, into useful materials. On the other hand, little focus has been given to study the potential uses of high calcium fly ashes (HCFAs), which are also produced in Europe and constitute the half of total fly ash output.In this paper, a calcareous fly ash (F) from Agios Demetrios power plant in Greece was studied in combination with different alumino-silicate materials such as pozzolan, diatomite and brick dust in order to improve their physico-mechanical characteristics. Pastes were mixed with an alkaline activator, which consists of a sodium silicate solution and sodium hydroxide solution 10M. The weight ratio of NaOH:Na2SiO3was 1:1. At the fresh state, setting time of the mixture was measured after mixing. Prismatic specimens were matured at different temperature conditions (25°C for 2 days and 65°C for 2 days). The samples were tested under flexural and compressive strength at the ages of 2, 7 and 28 days. Volume deformation and open porosity were also determined.

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Strzałkowska, Ewa. "Variability Qualitative Phase Composition of the Different Grain Classes of the Calcareous Fly Ashes." Archives of Mining Sciences 62, no. 1 (March 1, 2017): 225–37. http://dx.doi.org/10.1515/amsc-2017-0017.

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Abstract The results of studies of the phases composition of the different grain classes of calcareous fly ash were presented in this article. It was necessary to use three analytical methods: thermal, X-ray and microscopic to identify properly additional mineral phases in different grain classes of fly ash. These mineral phases were not determined during analysis of the sample which was not devided into grain classes. The minerals: quartz, anhydrite, calcite, bassanite, hannebahite hematite, magnetite, gehlenite, anorthite and CaO were identified. The thickest grain class of the tested ash characterized by a higher content of unburned fragments of coal. The presence of coal grains has negative influence at any further applications of the ash.

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Kim, Bumjoo, and Monica Prezzi. "Evaluation of the mechanical properties of class-F fly ash." Waste Management 28, no. 3 (January 2008): 649–59. http://dx.doi.org/10.1016/j.wasman.2007.04.006.

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Siddique, Rafat. "Properties of self-compacting concrete containing class F fly ash." Materials & Design 32, no. 3 (March 2011): 1501–7. http://dx.doi.org/10.1016/j.matdes.2010.08.043.

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Mehta, PK, GM Giaccio, and VM Malhotra. "Concrete Incorporating High Volumes of ASTM Class F Fly Ash." Cement, Concrete and Aggregates 10, no. 2 (1988): 88. http://dx.doi.org/10.1520/cca10088j.

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Xie, Zhaohui, and Yunping Xi. "Hardening mechanisms of an alkaline-activated class F fly ash." Cement and Concrete Research 31, no. 9 (September 2001): 1245–49. http://dx.doi.org/10.1016/s0008-8846(01)00571-3.

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Arora, Sunil, and Ahmet H. Aydilek. "Class F Fly-Ash-Amended Soils as Highway Base Materials." Journal of Materials in Civil Engineering 17, no. 6 (December 2005): 640–49. http://dx.doi.org/10.1061/(asce)0899-1561(2005)17:6(640).

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