The effect of using fly ash on the strength and hydration characteristics of blended cements

Koçak, Yılmaz; Nas, Suna

doi:10.1016/j.conbuildmat.2014.09.048

Cited by 143 publications

(70 citation statements)

References 29 publications

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“…When fly ash is used as clinker replacement in Portland-composite cement, additional hydration products can be expected due to the reaction of FA with the calcium hydroxide dwelling from hydration of OPC [54]. This additional chemical activity has an influence both on mechanical properties [67] and on the heat generated during hydration [68]. Contrary to FA, CF shows only a poor chemical activity.…”

Section: Strength Activity Index Methods Was Used In Order Tomentioning

confidence: 99%

Ability of Two Dam Fine-Grained Sediments to be Used in Cement Industry as Raw Material for Clinker Production and as Pozzolanic Additional Constituent of Portland-Composite Cement

Faure

Smith

Coudray

et al. 2017

Waste Biomass Valor

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other one is calcined in the range 550-1000 °C aiming to obtain a pozzolanic reactive material that could be used as supplementary cementitious material in blended Portland cement. After thermal treatments, the products are characterized and compared to ordinary Portland cement (OPC) and to pozzolanic active materials (fly ash from pulverized-coal power plant). Results showed that each sediment is suitable for the only tested reuse option. For the clinker prepared with SEP sediment, the morphology and the mineralogical composition correspond to those of a typical Portland clinker. Concerning calcined STA pozzolanic activity, the optimum thermal treatment was found to be 900 °C using the chemical Frattini test. Similar compressive strength results were obtained with calcined STA and silico-aluminous fly ash.Abstract Fine-grained sediment deposition is a phenomenon that occurs at different extents in all the reservoirs. This particle accumulation has to be properly managed, in accordance with the operational needs and the environment. As an extracted and on-land managed sediment has to be considered as a waste material according to both European and French regulations, sustainable reuse options need to be investigated. One of them could be a beneficial reuse as a raw material in cement industry either as partial substitution in Portland clinker raw mix or as a supplementary cementitious material (SCM) after thermal treatment in order to activate its possible pozzolanic activity. Two dredged materials, labelled SEP and STA, both from French hydroelectric reservoirs, are characterized on physical, chemical and mineralogical aspects. SEP is used as raw material partial replacement for clinker synthesis and the The original version of this article was revised due to a retrospective Open Access order.

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Section: Strength Activity Index Methods Was Used In Order Tomentioning

confidence: 99%

Ability of Two Dam Fine-Grained Sediments to be Used in Cement Industry as Raw Material for Clinker Production and as Pozzolanic Additional Constituent of Portland-Composite Cement

Faure

Smith

Coudray

et al. 2017

Waste Biomass Valor

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“…On the other hand, comparing VCAS with fly ash, a pozzolanic material that can be used to replace OPC in high percentages, it can be observed that fly ash blended mortars present a significant reduction in the CSI, from 0.73-0.90, depending on the amount of fly ash, 10-25% [27]. Nevertheless, VCAS blended mortars do not present any significant reduction for the compressive strength index, even using a high percentage of VCAS replacing OPC.…”

Section: Compressive Strength Of Mortarsmentioning

confidence: 99%

“…The k-factor values have been calculated for VCAS in the 10-30% replacing range for mortars. Rao [27] analyzed the behaviour of compressive strength in Portland cement mortars, and he proposed empirical model expressions to predict the compressive strength dependence in terms of the water/cement (w/c) ratio. The first expression proposed by Rao [28] was as shown in Eq.…”

Section: Compressive Strength Of Mortarsmentioning

confidence: 99%

Assessment of pozzolanic/hydraulic reactivity of vitreous calcium aluminosilicate (VCAS)

et al. 2016

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The aim of this paper is to assess the possibility of using vitreous calcium aluminosilicate (VCAS) as a supplementary cementitious material in the production of Portland cement mortars. The calcium hydroxide consumption by VCAS is assessed by two different methods: firstly, a classical method based on thermogravimetric analysis (TGA) and, secondly, pH and electrical conductivity measurements of calcium hydroxide/VCAS suspensions with excess calcium hydroxide. Evidence of pozzolanic reactivity of VCAS is revealed in hydrated lime pastes, and low reactivity was observed in aqueous suspensions.The reactivity of VCAS is also assessed by means of TGA of VCAS/OPC pastes and by means of the mechanical strength development of Portland cement mortars, with VCAS replacement percentages in the range of 10-30%. The results obtained show that pozzolanic and hydraulic reactions take place in OPC systems. VCAS can be used as a supplementary cementitious material by replacing OPC at levels of 10-30% by mass.

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“…Kocak et al [19] reported that the use of fly ash without mechanical activation decreases the compressive strength of blended cements for all fly ash addition rates (5, 10, 15, 20 and 25%) compared to the reference value. However, the authors noticed an improved mechanical strength even below the reference indicating activation of pozzolanic reactions at a high curing time [19]. Mechanical activation of fly ash was conducted by Chen et al [18] to treat fly ash from a municipal solid waste incinerator.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, several authors have conducted studies on how to activate fly ash trough milling [5,17,18]. Kocak et al [19] reported that the use of fly ash without mechanical activation decreases the compressive strength of blended cements for all fly ash addition rates (5, 10, 15, 20 and 25%) compared to the reference value. However, the authors noticed an improved mechanical strength even below the reference indicating activation of pozzolanic reactions at a high curing time [19].…”

Section: Introductionmentioning

confidence: 99%

Effect of mechanical activation of fly ash added to Moroccan Portland cement

et al. 2018

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Abstract. Nowadays, the cement industry is the largest emitter of CO 2 . In 2015, cement production accounts for roughly 8% of global CO 2 emissions. In order to reduce this impact, cement plants are working on alternative solutions, for instance, producing cement by adding additives like fly ash known for reducing the emissions of CO 2 and minimizing production costs. The thermal power stations in Morocco produce more than 500 000 tons per year. For ecological and sustainable development reasons, it is desirable to recycle these quantities according to beneficial methods to their addition in the cement. This study aims to investigate the influence of grinding fly ash on the physico-chemical and mechanical properties of fly ash blended CPJ45 cement. The addition of the fly ash particles to the grinder leads respectively to the breakage of the particles and to reduce the agglomeration effect in the balls of cement grinder. Fly ash milling was found to improve particles fineness, and increase the silica and alumina content in the cement. Furthermore, milled fly ash blended cements show higher compressive strength compared to unmilled fly ash blended cements, due to improved fly ash reactivity through their mechanical activation.

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The effect of using fly ash on the strength and hydration characteristics of blended cements

Cited by 143 publications

References 29 publications

Ability of Two Dam Fine-Grained Sediments to be Used in Cement Industry as Raw Material for Clinker Production and as Pozzolanic Additional Constituent of Portland-Composite Cement

Ability of Two Dam Fine-Grained Sediments to be Used in Cement Industry as Raw Material for Clinker Production and as Pozzolanic Additional Constituent of Portland-Composite Cement

Assessment of pozzolanic/hydraulic reactivity of vitreous calcium aluminosilicate (VCAS)

Effect of mechanical activation of fly ash added to Moroccan Portland cement

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