Coal fly ash activation—Comparison of isothermal calorimetric data and mortar strength

Irbe, Linda; Urbonas, L.; Heinz, D.

doi:10.1016/j.tca.2017.12.002

Cited by 14 publications

(9 citation statements)

References 28 publications

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“…U cilju poboljšanja početnih svojstava ovih veziva (vreme vezivanja i početne čvrstoće) neophodno je TEHNIKA -NOVI MATERIJALI 29 (2020) 5 primeniti neki od postupaka povećanja reaktivnosti EFP, kao što su mehanička aktivacija [12,13], hemijska aktivacija [14,15] ili kombinacija obe metode [16,17]. Pod mehaničkom aktivacijom (MA) se podrazumeva povećanje reaktivnosti materijala postupkom mlevenja.…”

Section: Uvodunclassified

“…Do povećanja reaktivnosti dolazi usled kombinovanih efekata usitnjavanja čestica, povećanja specifične površine i fizičko-hemjskih promena koje nastaju kako na površini tako i u unutrašnjosti čestica materijala [18]. Smatra se da povećanje specifične površine EFP značajno ubrzava odigravanje pucolanske reakcije, što je posledica većeg kontakta između rastvora u porama i površine čestica, te lakšeg rastvaranja aluminatnih i silikatnih jona iz EFP [16,19]. Cilj hemijske aktivacije (HA) je obezbeđivanje alkalne sredine koja pospešuje rastvaranje EFP, a time i pucolansku reakciju [7,16].…”

Section: Uvodunclassified

“…Smatra se da povećanje specifične površine EFP značajno ubrzava odigravanje pucolanske reakcije, što je posledica većeg kontakta između rastvora u porama i površine čestica, te lakšeg rastvaranja aluminatnih i silikatnih jona iz EFP [16,19]. Cilj hemijske aktivacije (HA) je obezbeđivanje alkalne sredine koja pospešuje rastvaranje EFP, a time i pucolansku reakciju [7,16]. Umereno alkalne soli, kao što su natrijum-sulfat, natrijum-karbonat i sl, kao aktivatori veziva sa EFP, sve se više izučavaju, jer obezbeđuju generisanje neophodne alkalne sredine in situ, u reakciji aktivatora i portlandita, te se prilikom sinteze veziva izbegava korišćenje jakih alkalnih rastvora [14,16].…”

Section: Uvodunclassified

“…Svega nekoliko prethodnih istraživanja bavilo se ispitivanjem uticaja primene kombinacije mehaničke i hemijske aktivacije na svojstva veziva sa EFP [16,17]. Rezultati ovih analiza pokazali su da je pozitivno dejstvo hemijskih aktivatora bilo znatno veće ukoliko se EFP prethodno mehanički aktivira [16,17]. Udeo EFP u ispitivanim vezivima iznosio je 50%.…”

Section: Uvodunclassified

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Improving properties of high volume fly ash binder by mechanical and chemical activation

Rakić¹,

Baščarević²

2020

Tehnika

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High volume fly ash (FA) binders are characterized by long setting times and low early strength. By applying mechanical and/or chemical activation methods, it is possible to increase the reactivity of FA and improve the properties of the binder. In this paper, influence of mechanical activation of FA on the properties of binders prepared with 70% FA and 30% Portland cement was investigated. Additionally, effect of chemical activation of the binder by using sodium sulfate as activator was evaluated. The binder obtained by combining mechanical and chemical activation had the highest early strength (up to 7 days) and the shortest setting times. However, the highest strength of the binder after 90 days was obtained by applying only mechanical activation of FA.

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Section: Uvodunclassified

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Improving properties of high volume fly ash binder by mechanical and chemical activation

Rakić¹,

Baščarević²

2020

Tehnika

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“…A lot of research has been carried out on the disposal of waste containing heavy metals [1,2], especially that which also contains large amounts of silica, which are used in the creation of the cement matrix microstructure. Many studies have been conducted on the use and optimisation of the transformation process in cement slurries of silica fume (SF) [3][4][5], fly ash (FA) [6][7][8][9] or natural pozzolana, namely trass [10,11]. R-Mud also has interesting pozzolanic properties, such as the concrete additives mentioned above.…”

Section: Introductionmentioning

confidence: 99%

Comparison of pozzolanic activity of ilmenite MUD waste to other pozzolans used as an additive for concrete production

Bobrowicz

Chyliński

2020

J Therm Anal Calorim

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The article presents a comparison of pozzolanic activity of R-Mud, which is a by-product of TiO2, with known and long-used additives to cement and concrete. Tests were carried out comparing the amount of heat of the hydration of cement and cement with added R-Mud, silica fume, fly ash and trass. The reaction susceptibility of these additives with calcium hydroxide has also been studied using the thermogravimetric method. Results from this method have shown that the reactivity of R-Mud is high and at a similar level to silica fume, while it is much higher than the reactivity of fly ash or natural trass. The high level of pozzolanic reactivity of R-Mud has been confirmed by both isothermal calorimetry and thermogravimetry.

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Investigation of different ways of activation of fly ash–cement mixtures: part 2—mechanical activation

Wilińska,

Pacewska,

Ostrowski

2023

J Therm Anal Calorim

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Introducing supplementary cementitious materials (SCM), e.g. fly ash, into cement composite results in ecological benefits. However, in the case of high amount of SCM used as a replacement of a part of cement, there are problems related to the development of the desired properties of the final composite. Such mixtures often require activation. In the first part of this series of publications, the results of chemical activation (using Na2SO4 and Ca(OH)2) of a mixture with a very high content of fly ash were discussed. The aim of this work was to investigate the influence of mechanical activation on hydration and microstructure of the binder composed of 80% of fly ash and 20% of cement. Mechanical activation was performed using a planetary ball mill. The following instrumental methods were used to investigate the activated fly ash-cement pastes: calorimetry, TG/DTG, FTIR spectroscopy, X-ray diffraction and scanning electron microscopy (SEM) coupled with EDS. It was shown that concomitant grinding of cement and fly ash is more effective compared to separate grinding. Mechanism of hydration/activation of such mixtures was discussed in detail.

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Coal fly ash activation—Comparison of isothermal calorimetric data and mortar strength

Cited by 14 publications

References 28 publications

Improving properties of high volume fly ash binder by mechanical and chemical activation

Improving properties of high volume fly ash binder by mechanical and chemical activation

Comparison of pozzolanic activity of ilmenite MUD waste to other pozzolans used as an additive for concrete production

Investigation of different ways of activation of fly ash–cement mixtures: part 2—mechanical activation

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