Synthesis and characterization of mortars with circulating fluidized bed combustion fly ash and ground granulated blast-furnace slag

Chi, Maochieh

doi:10.1016/j.conbuildmat.2016.07.071

Cited by 46 publications

(18 citation statements)

References 28 publications

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“…In addition to prevent disposal, using fly ash as a cement replacement material means a significant reduction in CO 2 emissions related to industrial cement production from traditional raw materials (limestone and clay), and the preservation of natural resources can also be achieved. There are many promising studies that have investigated the use of FBC fly ash as a cement replacement material [3][4][5][6][7][8][9][10][11][12][13]. However, the use of FBC or biomass fly ashes as a partial cement replacement material is not allowed by the American standard ASTM 618 [14] or the European standard EN 450-1 [15], which are the standards governing the use of fly ashes as mineral admixtures in concrete.…”

Section: Introductionmentioning

confidence: 99%

Mechanically Treated Fly Ash from Fluidized Bed Combustion of Peat, Wood, and Wastes in Concrete

Ohenoja

Wigren²,

Österbacka

et al. 2019

Waste Biomass Valor

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Fly ash generation in fluidized bed combustion (FBC) is a critical issue in many countries due to its disposal is becoming increasingly restricted and expensive. Because of this, there is a demand for applications in which these types of fly ashes could be utilized efficiently. One promising use for FBC fly ashes is as a cement replacement material in mortar and concrete. The current concrete regulations do not allow the use FBC fly ash as a supplementary cementitious material, but it can be expected to be included in the standards in the future. The properties of FBC fly ashes typically do not fulfill the values set in the standards as such. This study aimed to establish whether the properties of fly ashes from FBC of peat, wood, and wastes can be modified by mechanical classification and grinding so that they meet the requirements of the standards. The sulfate and chloride content, the sum of the main components (Si, Al, Fe), and the fineness of material were analyzed before and after the classification and grinding processes. In addition, the mortar specimens were prepared by using the processed fly ash as a cement replacement material. It was found that air jet classification is an effective fractionating method for fly ashes that effectively removes sulfate and chloride into fine fraction. Classified and ground fly ashes are potential alternative cement replacement materials. It is possible to achieve 80% of the control sample's compressive strength and 90% of the control sample's flexural strength for mortars containing 20% of classified and ground FBC fly ashes. Graphical AbstractLow utilization potential fly ash Fine fraction: 10 -30% fly ash~ Hazardous components: heavy metals, SO 4 , Cl Coarse fraction: 70 -90% fly ash C hemical composition fulfills EN 450-1 concrete standard Waste disposal stabilization Grinding High value product, e.g. for concrete air air Air jet classificationThis study aimed to establish whether the utilization potential of fly ashes from FBC of peat, wood, and wastes can be improved in concrete by mechanical classification and grinding, which is not done earlier. We found that it is possible to modify these fly ashes to fulfill concrete standards. Usually it is thought that fly ashes from fluidized bed combustion are not suitable for standardized concrete, but this study shows that with treatments it is possible.

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Section: Introductionmentioning

confidence: 99%

Mechanically Treated Fly Ash from Fluidized Bed Combustion of Peat, Wood, and Wastes in Concrete

Ohenoja

Wigren²,

Österbacka

et al. 2019

Waste Biomass Valor

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“…These results may indicate limited possibility of FBC fly ashes use in cement materials in place of the cement, depending on their content, which is also emphasized by authors of work [1][2][3][4][5][6]9,[12][13][14] by explaining that with a large specific surface area connected with high open porosity of FBC ashes, which are the effect of conditions in which these ashes are formed.…”

Section: Porositymentioning

confidence: 62%

“…On the other hand, due to presence of calcium sulphate in their composition, they may be used as a time controller for cement binding process [3,5,12]. In recent years a few studies have been published, where authors demonstrate that the total replacement of general purpose cement with the ash -slag binder, allows to get materials with increased durability [1][2][3][4][5][6]9,12]. According to some researchers, the quantity of FBC fly ashes introduced into cement may reach from 15% to 30% by mass.…”

Section: Introductionmentioning

confidence: 99%

Use of fly ash from fluidized bed boilers in clinker-slag-ash based binders

Janowska-Renkas

Kowalska

2018

MATEC Web Conf.

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Abstract. 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 -slagash 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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“…The compressive strength and bulk density were analyzed for physical/mechanical properties (Figure 1 The existing resources expect a decrease in the compressive strength with an increased content of FBC fly ash. 10,11,16 The compressive strength of the samples is the highest at a 10-% FBC fly-ash substitution. With an increased substitution, the strength is slightly decreased.…”

Section: Physical/mechanical Propertiesmentioning

confidence: 99%

“…Finally, calcium sulfate reacts with alumina hydroxide and calcium hydroxide to form ettringite, which increases its volume by up to 125 %. 6,[10][11][12] These negative properties of FBC fly ash can be eliminated with an autoclaving process. 12 AAC consists of a microporous binder matrix and air macropores.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of autoclaved aerated concrete using circulating fluidized-bed combustion fly ash

Šebestová¹,

Černý²,

Drochytka³

2020

Mater. Tehnol.

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The research deals with the possibility of maximum utilization of FBC fly ash in AAC technology and its impact on the properties of AAC. In the research, fly ash was used as a partial substitute for binder components in the AAC formulation. The amount of fly ash substitution was chosen on a scale of 10 % to 100 %. Physical-mechanical properties such as compressive strength and bulk density were determined on autoclaved samples. XRD analysis, SEM/EDX analysis were performed. Using these analyses, the change in the microstructure of autoclaved aerated concrete was monitored with increasing amount of FBC fly ash used. EDX microstructural tests have confirmed the incorporation of aluminum ions into the crystalline CSH. Further, an amount of crystalline tobermorite in the samples was observed which was almost constant up to 50 % of the FBC substitution. Compressive strength also began to decline significantly when the 50 % FBC fly ash substitution threshold was exceeded. The results thus show that the maximum FBC fly ash substitution is possible up to 50 %.Uporaba dimni{kega pepela, nastalega med zgorevanjem premogovega prahu v vrtin~asti plasti (CFBC) v izdelkih za gradbeni{tvo, je zahtevna zaradi njegove visoke vsebnosti`vepla. Mikrostruktura v avtoklavih prezra~enega betona (AAC) pa se spremeni v hidrotermalnih pogojih in tvorijo se kristalini~ni kalcij-silikatni hidrati (CSH). Ti so sposobni vezati v svojo strukturo kalcijev sulfat, ki ga vsebuje CFBC dimni{ki pepel. V raziskavi avtorji ugotavljajo kak{na je {e maksimalna mo`na koli~ina dodanega CFBC dimni{kega pepela v beton, izdelan z AAC tehnologijo in njen vpliv na lastnosti tako izdelanega AAC. V raziskavi so avtorji nadome{~ali`ivo apno z dimni{kim pepelom v skladu z AAC receptom. Nato so iz izdelanega betona naredili preizku{ance in dolo~ili njegove fizikalno-mehanske lastnosti, kot sta: tla~na trdnost in volumska gostota. Rezultati raziskave jasno ka`ejo mo`nost uporabe nadomestka v obliki dimni{kega pepela v koli~ini do 50 %. Nadalje so izvedli {e XRDin SEM/EDX-analize, ki so potrdile spremembe mikrostrukture prezra~enega betona zaradi uporabe pove~ane koli~ine CFBC dimni{kega pepela. EDX mikrostrukturne analize so potrdile vgradnjo aluminijevih ionov v kristalini~ni CSH. Klju~ne besede: v avtoklavih prezra~eni beton (AAC), zgorevanje premoga v vrtin~asti plasti (CFBC), dimni{ki pepel, tobermorit, zmanj{anje emisij 157

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Synthesis and characterization of mortars with circulating fluidized bed combustion fly ash and ground granulated blast-furnace slag

Cited by 46 publications

References 28 publications

Mechanically Treated Fly Ash from Fluidized Bed Combustion of Peat, Wood, and Wastes in Concrete

Mechanically Treated Fly Ash from Fluidized Bed Combustion of Peat, Wood, and Wastes in Concrete

Use of fly ash from fluidized bed boilers in clinker-slag-ash based binders

Experimental study of autoclaved aerated concrete using circulating fluidized-bed combustion fly ash

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