C4A3Š hydration in different alkaline media

Sánchez-Herrero, M. J.; Fernández-Jiménez, Ana; Palomo, A.

doi:10.1016/j.cemconres.2013.01.008

Cited by 79 publications

(34 citation statements)

References 44 publications

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“…Hydrates formed in sprayed pastes are hexagonal plates presenting an Al/S ratio equal to 7.0 and an elevated sodium content. This aluminate hydrate may be an AFm phase denominated U-phase and was also reported by [37][38][39] in cement systems containing sodium concentration above 0.40 mol/l. The sprayed paste CEM I_ALK_SP_0.32 presents a propitious sodium concentration in the liquid phase for U-phase formation (0.58 mol/L, Table 5).…”

Section: Sem and Eds Microanalysismentioning

confidence: 74%

Influence of spraying on the early hydration of accelerated cement pastes

Salvador

Cavalaro

Cano³

et al. 2016

Cement and Concrete Research

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In practice, most of the studies about the interaction between cement and accelerators is performed with hand-mixed pastes. However, in many applications mixing occurs through spraying, which may affect accelerators reactivity and the microstructure of the hardened paste. The objective of this study is to analyze how the mixing process influences the early hydration of accelerated cement pastes. Isothermal calorimetry, X-ray diffraction, thermogravimetry and SEM imaging were performed on cement pastes produced by hand-mixing and by spraying, using equivalent doses of an alkali-free and an alkaline accelerator and two types of cement. Results showed a great influence of the spraying process on the reactivity of accelerators and on the morphology of the precipitated hydrates. Variations in hydration kinetics caused by the mixing method are explained and the results obtained might have a significant repercussion on how future research on the behavior of accelerated mixes will be performed.Peer ReviewedPostprint (author's final draft

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Section: Sem and Eds Microanalysismentioning

confidence: 74%

Influence of spraying on the early hydration of accelerated cement pastes

Salvador

Cavalaro

Cano³

et al. 2016

Cement and Concrete Research

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“…CSA cements require smaller amounts of limestone in the raw material to be decarbonized and require a lower sintering temperature (around 1250°C) when compared to portland cement . When compared with portland cement clinkers, CSA cement clinkers tend to be more friable due to their high porosity and hence require less electricity to grind . CSA cements have a number of positive attributes such as rapid setting and rapid hardening, shrinkage compensating and self‐leveling depending on the amount of calcium sulfate added and the type of calcium sulfate (anhydrite or gypsum).…”

Section: Introductionmentioning

confidence: 99%

Nanostructural characterization of Al(OH)₃ formed during the hydration of calcium sulfoaluminate cement

et al. 2018

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Ye'elimite (Ca4Al6SO16) is a main mineral in calcium sulfoaluminate cements. Aluminum hydroxide is one of the products formed by hydration of ye'elimite. To characterize this phase, various aluminum hydroxides were synthesized from their chemical constituents using sol‐gel processing and compared with the aluminum hydroxide formed during the hydration of ye'elimite. The nanostructure of aluminum hydroxide formed during the hydration of ye'elimite was investigated in detail using X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy, inductively coupled plasma optical emission spectroscopy, and 27Al magic angle spinning nuclear magnetic resonance spectroscopy. No evidence was observed that indicated the existence of amorphous aluminum hydroxide in the hydration of ye'elimite. The pH values, thermogravimetric analysis, particle morphology, and Al‐O coordination indicated that the aluminum hydroxide from the hydration of ye'elimite had a crystal‐like structure. The X‐ray diffraction analysis, particle sizes, and ion activity product showed that the aluminum hydroxide from the hydration of ye'elimite had a microcrystalline structure.

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“…The ye'elemite clinker is also highly porous and this implies a reduction in production costs (17). C 4 A 3 S shows low alcalinity, suitable mechanical properties, appropriate stability in sea water (18,19), can be used to for stabilizing dangerous wastes and fixation of heavy metals (20)(21)(22) and they are resistant to carbonation (23). The ye'elemite clinker has been also used as a partial or total substitute of CPO in order to reduce shrinkage and reduce setting time in special applications (24).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and mechanical properties of a calcium sulphoaluminate cement made of industrial wastes

et al. 2014

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Environmentally-friendly calcium sulphoaluminate clinkers were obtained from a mixture of aluminium dross, fluorgypsum, fly ash and CaCO 3 at temperatures within the range of 1100 to 1400 °C. After the heat treatments Ca 4 Al 6 O 12 SO 4 was the main phase. Three different cements were prepared using the clinkers synthesized at 1250, 1350 and 1400 °C; the clinker powders were mixed with 20 wt% of hemihydrate. Cement pastes were prepared using a water/cement ratio (w/c), 0.4 followed by curing at 20 or 40 °C for periods of time ranging from 1 to 28 days. Most of the samples showed high compression strengths 40-47 MPa after 28 days, which were comparable to the strength of Portland cement. Ettringite was the main hydration product and its morphology consisted of acicular and hexagonal plates, which is typical of this phase.

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C4A3Š hydration in different alkaline media

Cited by 79 publications

References 44 publications

Influence of spraying on the early hydration of accelerated cement pastes

Influence of spraying on the early hydration of accelerated cement pastes

Nanostructural characterization of Al(OH)₃ formed during the hydration of calcium sulfoaluminate cement

Synthesis and mechanical properties of a calcium sulphoaluminate cement made of industrial wastes

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C4A3Š hydration in different alkaline media

Cited by 79 publications

References 44 publications

Influence of spraying on the early hydration of accelerated cement pastes

Influence of spraying on the early hydration of accelerated cement pastes

Nanostructural characterization of Al(OH)3 formed during the hydration of calcium sulfoaluminate cement

Synthesis and mechanical properties of a calcium sulphoaluminate cement made of industrial wastes

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Product

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Nanostructural characterization of Al(OH)₃ formed during the hydration of calcium sulfoaluminate cement