Mechanical and microstructural characterization of alkali sulfate activated high volume fly ash binders

Dakhane, Akash; Tweedley, Shannon Elizabeth; Kailas, Siva; Marzke, R. F.; Neithalath, Narayanan

doi:10.1016/j.matdes.2017.03.021

Cited by 63 publications

(35 citation statements)

References 39 publications

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“…They confirm acceleration of setting in the presence of Class C fly ash compared to samples composed of Class F fly ash. Compressive strength, both early and after 28 days, for binders containing calcium fly ash was also higher than for those with Class F fly ash and microstructure was more compact [62]. Güneyisi and Gesoglu [63] show that in case of high replacement (60 and 80%) of cement by Class C fly ash rapid setting occurs and initial time of setting is reduced.…”

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

confidence: 95%

“…It indicated that calcium fly ash used in high amount did not fully replace cement in these compositions. Dakhane et al [62] investigated mixtures containing higher amount; it is 70% of Class C fly ash. They confirm acceleration of setting in the presence of Class C fly ash compared to samples composed of Class F fly ash.…”

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

confidence: 99%

“…In case of high lime content in the reacting solution, formation of C-A-S-H gel is favoured. Secondary products such as: ettringite, carbonates, etc., appear depending on the type of activator used as well as conditions of reaction [19,43,62,105]. Na 2 SO 4 is known not only as component contributing to the increase in pH and improving ash solubility.…”

Section: Moderate Alkali Activationmentioning

confidence: 99%

“…They may also appear as component of some types of fly ashes. Dakhane et al [62] found that in case of Class C fly ash containing mixture (the level of cement replacement was 70%), activation with Na 2 SO 4 resulted in the formation of ettringite as well as higher degree of polymerisation of silica was affirmed earlier than in case of low-calcium fly ash binder. Main product of hydration/activation was gel of (N,C)-A-S-H in case of binders containing low-calcium fly ash and C-A-S-H in case of sample containing higher amount of calcium components.…”

Section: Moderate Alkali Activationmentioning

confidence: 99%

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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: 95%

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

confidence: 99%

Section: Moderate Alkali Activationmentioning

confidence: 99%

Section: Moderate Alkali Activationmentioning

confidence: 99%

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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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“…Paya et al showed that grinding y ash to ner particles can obviously hasten the hydration of y ash, but this method will lead to energy consumption [21]. Dakhane et al reported that pH-neutral alkali sulfates could activate y ash, resulting in 70% reduction of clinker factor [22]. Sodium sulfate can also activate the pozzolanic reaction of y ash, but this kind of chemical has negative e ect on long-term performance of cement-based materials [23].…”

Section: Introductionmentioning

confidence: 99%

Effect of TIPA on Chloride Immobilization in Cement‐Fly Ash Paste

Zhang

Tan

et al. 2018

Advances in Materials Science and Engineering

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Utilization of sea sands and coral aggregate for concrete in ocean construction is increasingly attracting the attention all over the world. However, the potential risk of steel corrosion resulting from chloride in these raw materials was one of the most concerned problems. To take this risk into account, chloride transporting to the surface of steel should be hindered. e formation of Friedel's salt in hydration process is widely accepted as an effective manner for this hindrance. In this study, an attempt to hasten the formation of Friedel's salt by adding triisopropanolamine (TIPA) was done in the cement-fly ash system, with intention to chemical bind chloride, and the chloride-binding capacity at 60 d age was examined. e results show that TIPA can enhance the chloride-binding capacity of cement-fly ash paste at 60 d age, and the reason is that the formation of Friedel's salt can be accelerated with addition of TIPA. e mechanism behind is revealed as follows: on the one hand, the accelerated cement hydration provides more amount of calcium hydroxide to induce the pozzolanic reaction of fly ash, which can hasten the dissolution of aluminum into liquid phase; on the other hand, TIPA can directly hasten the dissolution of aluminum in fly ash, offering more amounts of aluminum in liquid phase. In this case, the aluminum/sulfate (Al/S) ratio was obviously increased, benefiting the formation of Friedel's salt in hydration products. Such results would expect to provide useful experience to promote the chloride-binding capacity of cement-fly ash system.

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Influence of high-volume electric furnace nickel slag and phosphorous slag on the properties of massive concrete

Wang

Huang

Wang

2017

J Therm Anal Calorim

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Mechanical and microstructural characterization of alkali sulfate activated high volume fly ash binders

Cited by 63 publications

References 39 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

Effect of TIPA on Chloride Immobilization in Cement‐Fly Ash Paste

Influence of high-volume electric furnace nickel slag and phosphorous slag on the properties of massive concrete

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