Effect of ultrafine fly ash on mechanical properties of high volume fly ash mortar

Supit, Steve W.M.; Shaikh, Faiz Uddin Ahmed; Sarker, Prabir Kumar

doi:10.1016/j.conbuildmat.2013.11.002

Cited by 132 publications

(73 citation statements)

References 9 publications

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“…Jaturapitakkul et al [79] Influence of selected activating methods on hydration processes... reaction and densification of the structure. However, despite an enhancement effect of ultrafine fly ash, 28-day compressive strength of mortars containing very high volume fly ash binder was more than three times lower as compared for reference Portland cement mortar [76]. Similarly, Roychand et al [80] showed that 80% replacement of Portland cement by ultrafine fly ash results in significant reduction in compressive strength as compared to Portland cement reference mortar.…”

Section: Mechanical 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: Mechanical Activationmentioning

confidence: 99%

“…Thus, grinding process aimed in obtainment of fly ash of even more fragmentation is also desirable. Ultrafine fly ash exhibiting an average particle size of less than 10 lm may be produced during highenergy mechanical milling with the use of grinding aids to improve grinding efficiency [75,76].…”

Section: Mechanical Activationmentioning

confidence: 99%

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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“…Specific mass, compressive and flexural strength at 1, 7, 28, and 84 days (T = 20 • C, specimens soaked into water) were also determined on prismatic specimens according to EN 1015-11 [36] (four specimens for each mixture and age). Strength activity index (K: compressive strength of FA or UFFA mortar compared to that of the reference mortar containing cement only) was evaluated according to EN 450-1 [26] and Supit et al [27] at different ages. The aim of the research is the evaluation of strength activity index of the most widely used cement in Europe in comparison to limits indicated by EN 206-1 [37].…”

Section: Methodsmentioning

confidence: 99%

“…Yazici et al [23] concluded that compressive and splitting tensile strength of UFFA-based concretes increased along UFFA fineness. Supit et al [27] noted that use of UFFA up to 15% in respect to binder mass determines a great improvement on compressive strength of HVFA mortars, especially at early ages, due to the larger specific surface area of ultrafine fly ash that promotes an increase in the amount of fly ashes involved in the pozzolanic reaction, an acceleration of this mechanism, and an improvement of both the transition zone and the microstructures of the matrix, especially in terms of porosity [28]. The same authors [29] investigated durability issues of concretes manufactured with UFFA characterized by mean size particles equal to 3.4 µm.…”

Section: Introductionmentioning

confidence: 99%

Plain and Ultrafine Fly Ashes Mortars for Environmentally Friendly Construction Materials

2018

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This paper is aimed to study the rheological and physical performance of mortars manufactured replacing Portland-based cements with low calcium siliceous fly ash (FA) or ultrafine fly ash (UFFA). Five different types of cement (CEM I, CEM II/A-LL, CEM III/A, CEM III/B, and CEM IV according to EN 197-1) were used. Mortars were manufactured with FA or UFFA replacing 5%, 15%, 25%, 35%, and 50% of cement mass. Results indicate that compressive strength of mortars with UFFA is considerably higher than that of mixtures containing traditional FA, both at early and long ages. Moreover, experimental data reveal that replacement of cement with up to 25% of UFFA determines higher compressive strength at 7, 28, and 84 days than plain mortars (containing cement only), regardless of the type of cement used. Mortars manufactured with 35% or 50% of UFFA show slightly lower or similar compressive strength compared to the reference mortar (containing cement only). In addition, the results show values of the strength activity index of mortars made with FA 25%, 23%, and 20% lower than the reference corresponding mortars (cement only) at 7, 28, and 84 days, respectively. The grinding of FA, despite resulting in an increase in production energy and CO 2 emissions compared to unmilled FA, allows a wide use of these SCM (Supplementary Cementitious Materials) in place of cement, reducing the environmental impact of mortars up to 40% at the 28-day strength class. The use of UFFA ensures better resistance in CaCl 2 -rich environments.

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“…The possibility of using red mud and coal industry by-products as a raw material for the production of cement based materials was investigated by Yao et al They found that the designed cementitious composite had higher strength than reference composite at the age of 6 and 12 months [4]. Cement mortar containing 8 % of ultrafine fly ash (UFFA) as a partial replacement of cement showed 27 % improvement in compressive strength at 7 days when compared to the control cement mortar [5]. This can be explained by accelerated hydration due to highly specific surface and pozzolanic activity of UFFA.…”

Section: Introductionmentioning

confidence: 99%

Possibility of using bottom ash in precast concrete products

Lakušić¹

2018

JCE

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Possibility of using bottom ash in precast concrete products Chemical, physical and mechanical properties of bottom ash from two thermal power plants were analysed in order to evaluate the quality of bottom ash and to determine the possibility of its use in composite materials. It was found that the bottom ash samples from both power plants show good properties enabling their practical use, and that they also meet most of the criteria specified for fly ash. Samples in which 4, 8, 12 and 16% of fine aggregate was replaced with bottom ash were tested. The results meet criteria of applicable regulations for concrete, which justifies the use of bottom ash in construction industry. Mogućnosti upotrebe pepela s dna peći u betonskim predgotovljenim proizvodimaKako bi se ocijenila kvaliteta pepela s dna peći i utvrdila mogućnost njegove upotrebe u kompozitnim materijalima, provedeno je ispitivanje njegovih kemijskih, fizikalnih i mehaničkih svojstava iz dvije termoelektrane.Utvrđeno je da uzorci pepela s dna peći iz obje elektrane pokazuju dobra svojstva koja upućuju na mogućnost njihove praktične primjene te da ispunjavaju većinu kriterija propisanih za leteći pepeo. Ispitani su uzorci s 4 %, 8 %, 12 % i 16 % zamjene sitnog agregata pepelom. Rezultati su zadovoljili kriterije propisa za beton, što opravdava upotrebom pepela s dna peći u građevinskoj industriji.

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Effect of ultrafine fly ash on mechanical properties of high volume fly ash mortar

Cited by 132 publications

References 9 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

Plain and Ultrafine Fly Ashes Mortars for Environmentally Friendly Construction Materials

Possibility of using bottom ash in precast concrete products

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