Comparative investigation of reactivity of different kinds of fly ash in alkaline media

Wilińska, Iwona; Pacewska, Barbara

doi:10.1007/s10973-019-08296-4

Cited by 27 publications

(9 citation statements)

References 83 publications

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“…Fly ash could be used as a low-cost aluminum source as an alternative way to reduce costs (Jankowski et al, 2006;Mohamed et al, 2003). Fly ash does not only provide aluminum for ettringite formation, but also promotes the rise of water alkalinity (Madzivire et al, 2010;Wilinśka & Pacewska, 2019).…”

Section: Precipitation With Calciummentioning

confidence: 99%

Treatment and reuse of solid materials containing inorganic sulfur compounds

Tichý¹,

Kijjanapanich²,

Lens³

2020

Environmental Technologies to Treat Sulphur Pollution: Principles and Engineering

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In the environment, different types of solid phase systems can contain high concentrations of inorganic sulfurous compounds, e.g. ores, soils and sediments. The key criterion in the assessment of environmental risks of inorganic sulfurous compounds present in these materials is whether they remain bound to the solid phase or whether they are mobilized into the solution. Mobility of inorganic sulfur in natural water/solid biphasic systems is predominantly controlled by oxidative or reductive changes and precipitation constants of sulfurous compounds. In anaerobic environments, sulfur is encountered in its most reduced form, i.e. sulfidic form. Owing to the poor solubility of most sulfidic compounds, sulfurous compounds are predominantly immobile in anaerobic environments. On the contrary, in aerobic environments, the most stable inorganic sulfur compound is sulfate, which is usually very soluble in water. Reductive and oxidative changes of inorganic sulfurous compounds often involve an interaction with protons. Sulfur reduction is usually accompanied with alkalization of the environment, whereas sulfur oxidation often results in acidification. The general overview of the effects of reductive and oxidative

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Section: Precipitation With Calciummentioning

confidence: 99%

Treatment and reuse of solid materials containing inorganic sulfur compounds

Tichý¹,

Kijjanapanich²,

Lens³

2020

Environmental Technologies to Treat Sulphur Pollution: Principles and Engineering

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“…Anhydrite, resulting from the capture of gaseous sulfur oxides by calcareous sorbent molecules, also reacts with water, forming dihydrate gypsum and ettringite, the crystallization of which leads to binding of the ash grout [8]. Silica, considered to be the most important pozzolanic component of conventional ashes, rarely occurs in FBC ashes as a vitreous phase and therefore exhibits low reactivity [8,34]. Dehydrated clay minerals (aluminosilicates), often highly porous, usually exhibit significant pozzolanic properties [26].…”

Section: Phase Compositionmentioning

confidence: 99%

“…The addition of ash in place of cement delays the setting of the grout slightly, but in a way that is acceptable according to PN-EN 450-1 [20] -the values do not exceed twice the time measured for the cement control sample. According to the literature, the influence of FBC ashes on the cement composite setting is ambiguous -the presence of active calcium oxide has an accelerating effect, while anhydrite may delay the cement setting [34].…”

Section: Properties Of Cement-based Composites With the Addition Of Bottom Ashmentioning

confidence: 99%

“…Modification may serve to alter the chemical composition, e.g., by separation into grain size fractions [7,10,26]. Generally speaking, the excessive sulfate content in FBC ash is considered problematic, while the highly desired components are the pozzolanic SiO2 and Al2O3 compounds, as well as the hydraulically reactive CaO [7,26,34]. Another group of modification methods is based on the change of certain physical properties without altering the composition.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Separated Fractions of Fbc Bottom Ash on Selected Properties of Cement Mortars

Kledyński

Krysiak

2020

Civil and Environmental Engineering Reports

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This paper discusses the effects of partial replacement of cement with fluidized bed bottom ash on the properties of mortars. The analyzed ash samples originating from four Polish power plants were separated by grain size selection into fine and coarse-grained fractions. This process leads to a creation of derivative samples of differing physical properties and, partially, phase compositions, as tested in XRD and TG analyses. Despite its high water demand, the obtained fine-grained fraction has the potential for application in cementbased composites as a reactive, pozzolanic additive. An acceptable activity index may be reached when the sulfate content is limited, implying benefits of combining the ash with low gypsum cements. The coarse-grained fraction is significantly less reactive, while a high silica and aluminate content is related to improved mechanical properties of the composite. It can, therefore, potentially be used as a quasi-inert additive or a substitute for sand.

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“…pH value of water extracts are alkaline (above 11) for both fly ashes. Other properties of PF and PK can be found in Wilińska and Pacewska (2019).…”

Section: Materials and Sample Preparationmentioning

confidence: 99%

Investigation of Portland cement composites containing high amounts of different kinds of fly ashes

Wilińska

Pacewska

Kubissa

2019

Modern Building Materials, Structures and Techniques (MBMST)

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Utilization of fluidized fly ash in cement composite is problematic, e.g. because of its changeable chemical composition and increased water demand of the mixture. However, this kind of by-product shows some self-cementing properties, which may be beneficial for low-cement mixtures. The article compares the impact of various kinds of fly ashes, i.e. fluidized fly ash and conventional one, and their mixtures on hydration of fly ash–cement compositions in relation to properties of final material. The amount of fly ash in the binder was 50 wt%. Calorimetry, thermal analysis (TG/DTG) and infrared spectroscopy were used. Compressive strength and water absorption of hardened composites were also registered. It was found that both fly ashes exhibit delay effect in fly ash-cement pastes which causes extension of initial setting time and lower heat released compared to the reference without fly ash. At later hydration days, fluidized fly ash develops higher pozzolanic activity than conventional one. Compositions with fluidized fly ash show better compressive strength compared to those containing conventional one. Mixing of different materials of high and low activity (fluidized and conventional fly ash in this case) seems to be a good way for creation of new cement replacement material.

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Comparative investigation of reactivity of different kinds of fly ash in alkaline media

Cited by 27 publications

References 83 publications

Treatment and reuse of solid materials containing inorganic sulfur compounds

Treatment and reuse of solid materials containing inorganic sulfur compounds

Effects of Separated Fractions of Fbc Bottom Ash on Selected Properties of Cement Mortars

Investigation of Portland cement composites containing high amounts of different kinds of fly ashes

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