Study of alkaline hydrothermal activation of belite cements by thermal analysis

Goñi, S.; Guerrero, A.

doi:10.1007/s10973-009-0140-2

Cited by 21 publications

(5 citation statements)

References 23 publications

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“…The C2S is characterized by a slow reaction of hydration that awards it specific properties. The interest for this phase is growing giving place to cement with high percentage of activated belite, named 'belite cements' [10].…”

Section: Introductionmentioning

confidence: 99%

“…Thermal analysis is a useful tool for quantifying different parameters of interest in the building materials, i.e. for evaluating the pozzolanic activity of waste additions to Portland clinker [29][30][31], for evaluating the effect of alkaline hydrothermal activation of fly ash belite cement [10] or kinetic equations of alkaline activation of blast furnace slag [32] and for quantitative determination of the chemical composition of the C-S-H gel and degree of hydration, which is the main aim of this study.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative study of hydration of C3S and C2S by thermal analysis

Goñi

Puertas

Hernández

et al. 2010

J Therm Anal Calorim

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This research is part of a European project (namely, CÓDICE project), main objective of which is modelling, at a multi-scale, the evolution of the mechanical performance of non-degraded and degraded cementitious matrices. For that, a series of experiments were planned with pure synthetic tri-calcium silicate (C3S) and bi-calcium silicate (C2S) (main components of the Portland cement clinker) to obtain different calcium-silicate-hydrate (C-S-H) gel structures during their hydration. The characterization of those C-S-H gels and matrices will provide experimental parameters for the validation of the multiscale modelling scheme proposed. In this article, a quantitative method, based on thermal analyses, has been used for the determination of the chemical composition of the C-S-H gel together with the degree of hydration and quantitative evolution of all the components of the pastes. Besides, the microstructure and type of silicate tetrahedron and mean chain length (MCL) were studied by scanning electron microscopy (SEM) and Si magic-angle-spinning (MAS) NMR, respectively. The main results showed that the chemical compositions for the C-S-H gels have a CaO/ SÍO2 M ratio almost constant of 1.7 for both C3S and C2S compounds. Small differences were found in the gel water content: the H 2 0/Si0 2 M ratio ranged from 2.9 ± 0.2 to 2.6 ± 0.2 for the C 3 S (decrease) and from 2.4 ± 0.2 to 3.2 ± 0.2 for the C 2 S (increase). The MCL values of the C-S-H gels, determined from 29 Si MAS NMR, were 3.5 and 4 silicate tetrahedron, for the hydrated C3S and C2S, respectively, remaining almost constant at all hydration periods. Keywords C-S-H gel • Chemical composition • Thermal analysis • C3S • C2S

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantitative study of hydration of C3S and C2S by thermal analysis

Goñi

Puertas

Hernández

et al. 2010

J Therm Anal Calorim

Self Cite

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“…The alkali Na + accelerated the formation of poorly crystallized calcium silicate hydrates [27,28,29] and calcium aluminate hydrates, as a network modifier for the structure. The OH − ions attacked and broke the Si–O–Si (Al) bonds, and then partly dissolved the amorphous phase to the mixtures.…”

Section: Discussionmentioning

confidence: 99%

A Kinetic Study of the Pozzolanic Reaction of Fly Ash, CaO, and Na2O in the Preparation of Fly Ash Belite Cement

Guo

Fang

et al. 2019

Materials

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Fly ash belite cement is a kind of low-carbon cement prepared by a two-step process involving hydrothermal synthesis and low-temperature calcination. Pozzolanic reaction pastes, as the precursors of fly ash belite cement prepared by hydrothermal synthesis, are affected mainly by reaction temperature, time, ratios of the mass of fly ash/lime (FA/CA), and the dosage of Na2O. The absorbance rate of CaO with reaction time was tested for all samples, and the reaction kinetic model and parameters of the granule-hydrothermal synthesis method were discussed. A kinetic model for the hydrothermal synthesis in the presence of Na2O was proposed based on the Kondo’s modified Jander equation and Arrhenius equation. The activation energy (Ea) of the process was determined to be 67.76 kJ/mol. In addition, with an increasing dosage of Na2O, the pre-exponential factor A of the Arrhenius equation increased. However, the hydrothermal reaction degree was accurately predicted using the kinetic model characterized by the absorption rate of CaO. The results indicated that Na2O, as an alkali activator, facilitated the diffusion of Ca2+ firstly, then partly dissolved the amorphous phase in the mixtures and, finally, accelerated the formation of poorly crystallized hydrates.

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“…It is followed by low-temperature burning at 600-1200 °C where we obtain a reactive belite phase with a high specific surface area [6]. Different types of fly ash can also be used as a raw material in this process and alkaline activation can be applied [7]. The hydrothermal method was also used in the preparation of sulphoaluminate belite binders with subsequent burning at 1050 °C compared to the temperature of 1250 °C in the usual method of producing this type of cement [8].…”

Section: Introductionmentioning

confidence: 99%

Low-temperature synthesis of binder with belite content

Staněk,

Rybová,

Khongová

et al. 2023

J. Phys.: Conf. Ser.

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Sol-gel methods or hydrothermal treatment in combination with low-temperature burning are used for low-temperature syntheses of hydraulically active dicalcium silicate. The paper describes a two-stage preparation process without the use of an autoclave. In the first phase, the precursors of hydraulically active phases are prepared. In the second phase, burning up to 1000 °C takes place to form a C2S-based binder. Unlike commonly used procedures of the sol-gel method, solid raw materials and water are used. The main raw materials are quicklime and a source of SiO2 and then various activators. X-ray diffraction analysis and electron microscopy methods were used for the research. The resulting binders are similar to hydraulic lime, they achieve low initial strengths, the long-term strengths are satisfactory. It is suitable for the preparation of mortars and plaster mixtures.

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Study of alkaline hydrothermal activation of belite cements by thermal analysis

Cited by 21 publications

References 23 publications

Quantitative study of hydration of C3S and C2S by thermal analysis

Quantitative study of hydration of C3S and C2S by thermal analysis

A Kinetic Study of the Pozzolanic Reaction of Fly Ash, CaO, and Na2O in the Preparation of Fly Ash Belite Cement

Low-temperature synthesis of binder with belite content

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