Chemical activation of hybrid binders based on siliceous fly ash and Portland cement

Alahraché, Salaheddine; Winnefeld, Frank; Champenois, Jean-Baptiste; Hesselbarth, Frank; Lothenbach, Barbara

doi:10.1016/j.cemconcomp.2015.11.003

Cited by 110 publications

(71 citation statements)

References 61 publications

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“…[38,50]. There is also confirmation about slow reaction of fly ash with Ca(OH) 2 and the fact that during early days, hydration of cement dominates reaction of mixture containing high amount of Class F fly ash and is mainly responsible for setting, hardening and development of early compressive strength [36]. The relationship showing that the higher is the content of fly ash introduced as Portland cement replacement, the greater is reduction in compressive strength repeatedly confirmed in studies by various authors, e.g.…”

Section: Early Hydration Of Non-activated Mixtures Containing High Anmentioning

confidence: 71%

“…Solutions of lower alkalinity may be used in this case, and high pH is generated in situ; thus, there is greater safety for workers and the environment. Moreover, the activators have relatively low impact on cement hydration and elevated temperature of hardening usually is not necessary [36,43]. In general, different products of reaction may appear with the use of solutions of alkali salts.…”

Section: Moderate Alkali Activationmentioning

confidence: 99%

“…Sodium hydroxide (Na ? , OH -) is also produced during the [16,19,36,43,49,60,74,103,110,115,116]. Ca(OH) 2 needed for the reaction may come from different sources: cement hydration, introduction of additional amount of Ca(OH) 2 into the system or as component of used supplementary cementitious material (e.g.…”

Section: Moderate Alkali Activationmentioning

confidence: 99%

“…It causes some ecological problems and raise in price of the final product. Some problems with safety of workers relating to using high alkaline solutions also appear [16,36]. Thus, recently, special emphasis is put to develop activated binders which can harden in more mild conditions.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Influence of selected activating methods on hydration processes of mixtures containing high and very high amount of fly ash

Wilińska

Pacewska

2018

J Therm Anal Calorim

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Binders containing fly ash as cement substitute have been used for many years. Typical amount of fly ash in cement composite does not exceed 35% of mass of binder. Replacement of substantial amount of cement mass by fly ash results in retardation of hydration of binder and deterioration of some concrete properties, e.g. delay in setting time and reduction in early compressive strength. These inconveniences may be reduced using proper method of activation. In this paper, possibilities to activate binding mixtures containing high and very high amount of fly ash and low amount of Portland cement were discussed basing on the literature reports as well as on our own research results. Several activating methods were described, such as mechanical activation, exchanging of part of components of binder (cement, fly ash or both of them) by more reactive fine-grained material, chemical activation by the use of alkaline activators as well as combined methods. Possibilities of using these methods were discussed in relation to amount of fly ash introduced as replacement of cement and kind of fly ash used. Usefulness of calorimetry and thermal analysis methods was also presented.

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Section: Early Hydration Of Non-activated Mixtures Containing High Anmentioning

confidence: 71%

Section: Moderate Alkali Activationmentioning

confidence: 99%

Section: Moderate Alkali Activationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of selected activating methods on hydration processes of mixtures containing high and very high amount of fly ash

Wilińska

Pacewska

2018

J Therm Anal Calorim

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“…The cost of manufacture and associated health risks make highly alkaline conditions unreasonable and one of the principle drawbacks of alkali-activated binder systems. The use of less concentrated activators including alkali carbonates and sulphates [19][20][21][22] and organic activators with carboxylate groups as summarised in [23] has been reported previously. Alternatively, activation using phosphoric acid has also shown promising results regarding durability with excellent resistance to elevated temperatures [24].…”

mentioning

confidence: 99%

Effects of waste glass on alkali-activated tungsten mining waste: composition and mechanical properties

Kastiukas

Zhou

2017

Mater Struct

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Increasingly more research is being directed towards the valorisation of waste materials as precursors for synthesising alkali-activated binders (AABs). For this study, varying blends of tungsten mining waste (TMW) and waste glass (WG) are activated using a combined sodium hydroxide (SH) and sodium silicate (SS) alkali solution. The activating solution itself is also varied with respect to the quantities of SS and SH to determine their effect on reactant formation and mechanical strength of TMWbased AABs. The results show that an increased WG content can effectively provide an additional source of reactive silica, contribute to the formation of (C, N)-A-S-H gel products and thus significantly improve the mechanical strength. High strength TMW-WG AABs were attributed to a faster TMW dissolution rate and dense microstructure. Such structures were characteristic of formulations with low alkali modulus (SiO 2 / Na 2 O \ 2) combined with a SS/SH weight ratio of 2.8. For the latter, not only was a characteristic slower strength development with increasing alkali content observed, but there was also a limit of alkali metal concentration (Na 2 O * 3.1%) beyond which the strength deteriorated. Furthermore, SEM micrographs disclose that unreacted particles of WG reinforced the matrix by acting as a filler.

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Assessment of the Effectiveness of Producing Mineral Fillers via Pulverization for Ceramic Coating Materials

Terzić

Pezo

2019

Photoenergy and Thin Film Materials

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Chemical activation of hybrid binders based on siliceous fly ash and Portland cement

Cited by 110 publications

References 61 publications

Influence of selected activating methods on hydration processes of mixtures containing high and very high amount of fly ash

Influence of selected activating methods on hydration processes of mixtures containing high and very high amount of fly ash

Effects of waste glass on alkali-activated tungsten mining waste: composition and mechanical properties

Assessment of the Effectiveness of Producing Mineral Fillers via Pulverization for Ceramic Coating Materials

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