Ettringite decomposition in the presence of barium carbonate

Carmona-Quiroga, Paula María; Blanco-Varela, María Teresa

doi:10.1016/j.cemconres.2013.05.021

Cited by 88 publications

(20 citation statements)

References 27 publications

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“…For pastes of C 4 A 3 $, obvious water loss can be observed around 180°C in a derivative curve, which is due to the dehydration of AFm (Winnefeld and Barlag, 2010). As regards the paste of C 3 ŠA 3 $, the most significant water loss occurs at the range of 100-120°C due to decomposition of AFt (Carmona-Quiroga and Blanco-Varela, 2013;Winnefeld and Barlag, 2010), and meanwhile a slight water loss can also be observed around 180°C, which indicates that AFt phases account for the majority of the hydration Figure 3. SEM-EDS analyses of C 3 ŠA 3 $: (a) SEM morphology of C 3 ŠA 3 $ particle; (b) elementary distribution of strontium on the particle; (c) elementary distribution of calcium on the particle; (d) elementary composition of the particle tested by EDS; (e) molar ratios of C 3 ŠA 3 $ obtained by testing different particles of C 3 ŠA 3 $ products of C 3 ŠA 3 $.…”

Section: Resultsmentioning

confidence: 97%

Characterisation and hydration process of synthetic Sr-bearing ye'elimite

Zhao

Chang

2018

Advances in Cement Research

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2+ions in C 4 A 3 $, Sr-bearing ye'elimite can be synthesised. In this paper, a kind of Sr-bearing ye'elimite was synthesised with the formula 3CaO·SrO·3Al 2 O 3 ·SO 3 (abbreviated as C 3 ŠA 3 $); the characterisation and hydration process of C 3 ŠA 3 $ are reported here. Comparing to C 4 A 3 $, mineralogical analysis of C 3 ŠA 3 $ was conducted, and Rietveld quantitative phase analysis was employed to quantify the hydration products of C 3 ŠA 3 $ and correlate to calorimetric data. Results show that C 3 ŠA 3 $ accounts for over 93% in the clinker, and the ACn contents are insignificant in terms of amounts. Without gypsum, the hydration process of C 3 ŠA 3 $ is more retarded and prolonged than C 4 A 3 $ at an early stage. In the hydration products of C 3 ŠA 3 $ at 28 d, AFt accounts for 28·2% and AFm occupies 13·4%; CAH 10 is quantified to be 5·5%. Compared to C 4 A 3 $, C 3 ŠA 3 $ tends to yield more AFt. As regards C 3 ŠA 3 $ hydrating with a certain amount of gypsum, the hydration rate of C 3 ŠA 3 $ is accelerated to approach C 4 A 3 $ blended with gypsum. In the paste of C 3 ŠA 3 $ blended with gypsum at 28 d, AFt occupies the majority of crystalline phases to take up 42·1%; minor phases AFm and strontium sulfate account for 3·1% and 7·4%, respectively.Rietveld refined weight fraction of zinc oxide R wp weighted-profile R value (%) r radius of ion W st weight fraction of added zinc oxide

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Section: Resultsmentioning

confidence: 97%

Characterisation and hydration process of synthetic Sr-bearing ye'elimite

Zhao

Chang

2018

Advances in Cement Research

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“…(1) transmission bands located near to 1600 cm -1 and between 3000 and 3750 cm -1 , which are related to O-H vibrations [29]; (2) a peak near to 1120 cm -1 typical of S-O bond stretching; (3) a peak of bending vibration, associated with the Al-O-H bond at 854 cm -1 ; (4) a second bending vibration at 620 cm -1 , attributed to the Ca--O-H bond; and (5) a third bending vibration at 420 cm -1 , also related to the S-O bond [55][56][57]. Comparing both spectra (Fig.…”

Section: Resultsmentioning

confidence: 98%

Kinetic and thermal decomposition of ettringite synthesized from aqueous solutions

Guimarães

Oliveira

Leão

2016

J Therm Anal Calorim

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The kinetics of the thermal decomposition of a synthetic ettringite sample was studied between 298 and 820 K in an inert atmosphere for the present work. The ettringite and its thermal decomposition products were characterized using X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. Four endothermic events were observed with thermogravimetry curves, the maxima of which occurred at 366, 397, 537, and 641 K. All events were associated with the loss of water molecules with different degrees of interaction within the ettringite structure. Chemical equations for each decomposition step were proposed based on the percentages of mass loss observed. In addition, for the first time, the activation energies of each ettringite decomposition events were determined by the isoconversional methods of Ozawa-Flynn-Wall, Friedman, and Kissinger-AkahiraSunose. The modeling revealed that the activation energy varied from *50 kJ mol -1 , characteristic of mass transfer control steps, to *150 kJ mol -1 , which is typical of chemical control, as the temperature increased and the ettringite structure lost water. A total of 32 mol of water was released equivalent to 43.1 % of the initial sample mass.

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“…The panel contained macropores, with a size range of approximately 5 to 50 µm, formed by the zeolite 13X particles in the calcium aluminate cement matrix that were irreversibly adsorbed at the liquid-gas interfaces. If an ettringite phase had been generated, the majority of these macropores would have decomposed during the hydration process in the presence of lithium carbonate, similar to the case of barium carbonate [30]. The macropores were highly inter-connected with neighbouring macropores through voids within the strut walls.…”

Section: Resultsmentioning

confidence: 99%

A self-setting particle-stabilized porous ceramic panel prepared from commercial cement and loaded with carbon for potential radar-absorbing applications

Ryung

Lee

et al. 2018

PAC

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Porous ceramic materials are in a current research focus because of their outstanding thermal stability, chemical stability and lightweight. Recent research has widened the range of applications to radar absorption to utilize the advantages of porous ceramic materials. There has been long-standing interest in the development of lightweight radar-absorbing materials for military applications such as camouflaging ground-based facilities against airborne radar detection. Therefore, in this study, a novel lightweight radar-absorbing material for X-band frequencies was developed using a self-setting particle-stabilized porous ceramic panel composited with carbon. The panel was prepared using a commercial calcium aluminate cement (as a self-setting matrix), zeolite 13X particles with propyl gallate (as a particle-stabilized pore former) and carbon (as a radar-absorbing material). The panel contained macropores approximately 200 to 400 µm in size formed by zeolite 13X particles that are irreversibly adsorbed at liquid-gas interfaces. The self-setting particle-stabilized porous ceramic panels were characterized by scanning electron microscopy, mercury porosimetry, physisorption analysis, capillary flow porosimetry and network analysis. When 0.2 wt.% carbon was added to a selfsetting particle-stabilized porous ceramic panel to fabricate a composite 7 mm thick, the maximum reflection loss was −11.16 dB at 12.4 GHz. The effects of the amount of added carbon and the thickness variation of a self-setting particle-stabilized porous ceramic panel on the radar-absorbing properties remain important issues for further research.

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Ettringite decomposition in the presence of barium carbonate

Cited by 88 publications

References 27 publications

Characterisation and hydration process of synthetic Sr-bearing ye'elimite

Characterisation and hydration process of synthetic Sr-bearing ye'elimite

Kinetic and thermal decomposition of ettringite synthesized from aqueous solutions

A self-setting particle-stabilized porous ceramic panel prepared from commercial cement and loaded with carbon for potential radar-absorbing applications

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