Metakaolin sand–blended-cement pastes: Rheology, hydration process and mechanical properties

Janotka, Ivan; Puertas, Francisca; Palacios, Marta; Kuliffayová, M.; Varga, Csilla

doi:10.1016/j.conbuildmat.2009.10.028

Cited by 108 publications

(46 citation statements)

References 21 publications

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“…In addition, the intensity of Q 2 (1Al) peak is higher in the latter composites. Both facts confirm the higher reactivity of MK-3 due to its higher metakaolinite content and fineness as our previous study concluded [58]. Al [6] Al [6] Al [5] Al [4] In stratlingite ppm Al [4] In C-S-H Al [4] PCMK Al [4] In stratlingite ppm Al [6] Al [6] Al [5] Al [4] In C-S-H Al [4] PCMK ppm Al [6] Al [6] Al [5] Al [4] In stratlingite Al [4] In C-S-H Al [4] PCMK-3/40 PCMK-3/20 PCMK-3/10 MK-3 Fig.…”

Section: Resultssupporting

confidence: 89%

“…This material is not suitable for ceramic and glass industry as input raw material even after laboratory-made treatment [53][54][55]. However, the utilization of metakaolin sands derived from relevant kaolin sands-as alternative for cement industry is possible [56][57][58][59][60]. The effect of three types of metakaolin sand with different metakaolinite content used as a various substitution level of PC on mechanical strengths, phase composition and pore structure development is reported in the paper.…”

Section: Lagier and Kurtismentioning

confidence: 99%

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Performance of composites with metakaolin-blended cements

Krajči

Mojumdar

Janotka

et al. 2014

J Therm Anal Calorim

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Nowadays the blended cements acquire the merit of high significance due to the thermal, energetic and ecological demands for ordinary Portland cement (PC) production. Metakaolin as a partial substitute of PC represents important pozzolana contributing to production of effective cement composites with high quality. Pozzolanic reaction of metakaolinite with PC in the presence of water is main reason of this statement. Comparison of three types of metakaolin sand (fineness below 60 lm) with different metakaolinite content (31-40 mass%) is presented in this study. The substitution of PC with metakaolin sand of the maximal metakaolinite content (40 mass%) leads to the highest compressive strengths of relevant composites. This is valid for composites with the highest substitution of PC by metakaolin sand in specimens (20 and 40 mass%). The best effectiveness of pozzolanic reaction is given especially by the highest consumption of portlandite which represents composite with the maximal metakaolinite content in metakaolin sand (40 mass%) and the higher substitution level of PC by metakaolin sand in specimens. This fact is connected with the improvement of pore structure parameters resulting in the pore structure refinement as well as permeability decreases. Both 29 Si MAS NMR and 27 Al MAS NMR spectra of metakaolin sands and respective composites confirm the most intense pozzolanic reaction in the case of metakaolin sand with the highest metakaolinite content (40 mass%). The results are properly supplemented by scanning electron microscopy (SEM) identifying the formed typical phases. The study has shown that metakaolin sand with reduced metakaolinite contents is also applicable as a pozzolanic addition to PC in the on-coming building practice.

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Section: Resultssupporting

confidence: 89%

Section: Lagier and Kurtismentioning

confidence: 99%

Performance of composites with metakaolin-blended cements

Krajči

Mojumdar

Janotka

et al. 2014

J Therm Anal Calorim

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“…Metakaolin is produced by calcining kaolin at 650-800°C and is mainly amorphous [4]. MK needs aqueous calcium hydroxide produced during clinker hydration to form C-S-H or C-S, Al-H gels [5]. In addition, MK induces a filler effect to the mixture [6].…”

Section: Introductionmentioning

confidence: 99%

Various Durability Aspects of Calcined Kaolin-Blended Portland Cement Pastes and Concretes

Saillio

Baroghel-Bouny²,

Pradelle³

2015

RILEM Bookseries

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The use of calcined clay, in the form of metakaolin (MK), as a pozzolanic constituent for concrete has received considerable attention in recent years, due to the lower CO 2 emission of this supplementary cementitious material compared to the production of a classic portland cement. Furthermore, concretes incorporating MK show some improve durability properties. In this paper, the durability of concretes and cement pastes with MK as partial replacement of cement (10 and 25 %) has been investigated in comparison with CEM-I materials one. Water porosity, chloride migration and diffusion, electrical resistivity and natural and accelerated carbonation tests have been performed. In addition, microstructural study is performed to better understand the results on the durability indicators. The cement pastes microstructure was characterized not only by usual techniques such as mercury intrusion porosimetry, XRD and TGA-DTA, but also by 29 Si and 27 Al NMR spectroscopy. For example, Friedel's salt (chemical binding) has been quantified by 27 Al NMR spectroscopy and XRD on cement paste. In addition, the progress of the durability properties for various water curing times has been investigated. Results show an evolution of the properties, as a function of the cement replacement degree by MK, such replacement increases durability against chloride penetration but decreases resistance to carbonation. The aluminate phases equilibrium is modified in concrete with metakaolin in comparison with a CEM-I one. Both chemical and physical chloride binding increases with MK replacement. In addition, since portlandite quantity decreases in cement materials with MK, these materials are less resistant to carbonation process for a same exposure condition (time and CO 2 concentration).

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“…Metakaolin is a reactive aluminosilicate pozzolan obtained by thermal treatment of kaolin (at about 650 °C) and by grinding it to a high fineness. The use of metakaolin as a partial replacement for Portland cement clinker helps to obtain more eco-efficient cements (Krajčí et al 2007;Janotka et al 2010). The production of VP kaolin sand was about 20-30 kt per year.…”

Section: Origin Of the Samplementioning

confidence: 99%

Stability of kaolin sand from the Vyšný Petrovec deposit (south Slovakia) in an acid environment

Pentrák¹,

Madejová²,

Slávka³

et al. 2012

Geologica Carpathica

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Abstract:Comprehensive characterization of kaolin sand from the Vyšný Petrovec (VP) deposit in Slovakia by a variety of experimental methods was performed. The quantitative XRD analysis (RockJock software) revealed that the acid-untreated sample contained mainly kaolinite (~60 wt. %), a considerable amount of dioctahedral micas (~32 wt. %) and quartz (~7 wt. %). The Hinckley index (HI) and Aparicio-Galán-Ferrel index (AGFI) calculated from the 02l and 11l reflections showed medium-defect kaolinite to be present in the VP kaolin. The influence of the mineral composition of VP kaolin on its stability in 6 mol · dm -3 HCl at 95 °C was investigated. The solid reaction products were examined by chemical analysis; XRD and infrared spectroscopy in both middle (MIR) and near (NIR) regions. Considerably higher dissolution rate of Fe compared to Al indicated that Fe was bounded in a readily soluble phase rather than in kaolinite. While the MIR spectra confirmed the gradual release of the central atoms from the clay minerals layers and creation of amorphous silica upon acid treatment, the NIR spectra revealed the formation of Si-OH groups in the solid reaction product. Relatively high dissolution rate of VP kaolin resulted from the presence of small-grains of mediumdefect kaolinite and clay admixtures in VP kaolin sand.

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Metakaolin sand–blended-cement pastes: Rheology, hydration process and mechanical properties

Cited by 108 publications

References 21 publications

Performance of composites with metakaolin-blended cements

Performance of composites with metakaolin-blended cements

Various Durability Aspects of Calcined Kaolin-Blended Portland Cement Pastes and Concretes

Stability of kaolin sand from the Vyšný Petrovec deposit (south Slovakia) in an acid environment

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