Studies on thermal dehydration of the hydrated Ca7ZrAl6O18 at different water–solid ratios cured at 60 °C

Madej, Dominika; Szczerba, Jacek; Nocuń-Wczelik, Wiesława; Gajerski, R.; Hodur, Karolina

doi:10.1016/j.tca.2013.07.011

Cited by 15 publications

(28 citation statements)

References 16 publications

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“…calcium zirconium aluminate, Ca 7 ZrAl 6 O 18 , that shows incongruent melting point at 1550°C, has been found by Berezhnoi and Kordyuk [14]. Ca 7 ZrAl 6 O 18 is a hydratable compound [15][16][17][18][19] that reacts with water to yield calcium aluminate hydrates (C-A-H), aluminium hydroxide and calcium zirconate, CaZrO 3 . The degree of hydration of Ca 7 ZrAl 6 O 18 is determined by water addition, temperature and time [18].…”

Section: Introductionmentioning

confidence: 92%

“…Ca 7 ZrAl 6 O 18 is a hydratable compound [15][16][17][18][19] that reacts with water to yield calcium aluminate hydrates (C-A-H), aluminium hydroxide and calcium zirconate, CaZrO 3 . The degree of hydration of Ca 7 ZrAl 6 O 18 is determined by water addition, temperature and time [18]. The hydrogarnet phase (C 3 AH 6 ), a crystalline form of aluminium hydroxide (Al(OH) 3 ) and CaZrO 3 , was the product from the hydration of Ca 7 ZrAl 6 O 18 at 60°C [18].…”

Section: Introductionmentioning

confidence: 99%

“…The degree of hydration of Ca 7 ZrAl 6 O 18 is determined by water addition, temperature and time [18]. The hydrogarnet phase (C 3 AH 6 ), a crystalline form of aluminium hydroxide (Al(OH) 3 ) and CaZrO 3 , was the product from the hydration of Ca 7 ZrAl 6 O 18 at 60°C [18]. The hydrates CAH 10 , C 2 AH 8 and C 4 AH 19 , obtained at lower temperatures [16][17], are metastable phases that transform with time to more stable and denser cubic hydrogarnet C 3 AH 6 .…”

Section: Introductionmentioning

confidence: 99%

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PREPARATION OF Al₂O₃-CaAl₁₂O₁₉-ZrO₂ COMPOSITE CERAMIC MATERIAL BY THE HYDRATION AND SINTERING OF Ca₇ZrAl₆O₁₈-REACTIVE ALUMINA MIXTURE

Madej¹

2016

Ceramics - Silikaty

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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PREPARATION OF Al₂O₃-CaAl₁₂O₁₉-ZrO₂ COMPOSITE CERAMIC MATERIAL BY THE HYDRATION AND SINTERING OF Ca₇ZrAl₆O₁₈-REACTIVE ALUMINA MIXTURE

Madej¹

2016

Ceramics - Silikaty

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“…It is also well known that the hydraulic reactivity of these phases increases with the calcium content of the phase (CaO/Al 2 O 3 molar ratio), and therefore, C 7 A 3 Z shows higher reactivity than mineral phases of CACs. The formation and dehydration of a number of C-A-H-like phases of hydrated Ca 7 ZrAl 6 O 18 were investigated in previous works [6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…George [19] reports an endothermic peak due to dehydration of C 2 AH 8 at 170°C. Various authors [9,[20][21][22][23][24][25][26][27] have reported DTA curves including evidence for the presence stable cubic C 3 AH 6 . All report an endothermic peak due to dehydration somewhere in the range 300-330°C.…”

Section: Introductionmentioning

confidence: 99%

Hydration, carbonation and thermal stability of hydrates in Ca7−xSrxZrAl6O18 cement

Madej

2017

J Therm Anal Calorim

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This paper studies hydration stages and phase transformation mechanism of the Sr 2? -doped calcium zirconium aluminate cement at room temperature. Features of different hydration stages of this cement paste are identified by X-ray diffraction, scanning electron microscopy, differential thermal analysis, thermogravimetric analysis, evolved gas analysis and heat evolution test. It was found that the partial isovalent substitution of Ca 2? for Sr 2? such as Ca 7-x Sr x ZrAl 6 O 18 , with x = 0.3, 0.6, 1.0, reduced the hydraulic reactivity of Ca 7 ZrAl 6 O 18 phase. The course of hydration of mixed oxides of the type 6CaOÁSrOÁ3Al 2 O 3 Á ZrO 2 documented using microcalorimetry was supported by investigations of the solid hydration products. Research showed that the hexagonal hydrates were stable at early and middle curing ages, an indication that including Sr in solid solution could effectively inhibit the conversion from both C 4 AH 13-19 and C 2 AH 8 to C 3 AH 6 and AH 3 . Calcium monocarboaluminate C 4 A CH 11 phases were also found in this system due to the carbonation process of C 4 AH 13 phase. Substitution of Ca 2? ions by Sr 2? ions in hexagonal calcium aluminate hydrates causes structural disorder and then contributes to the broadening of lines in the powder X-ray diffraction patterns of layered structures of metastable hydrates. At later curing ages, the formation of two hydrogarnet phases, one Sr-rich (C,Sr) 3 AH 6 and the other Ca-rich (C,Sr) 3 AH 6 , was proved.

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Study of the hydration of calcium zirconium aluminate (Ca7ZrAl6O18) blended with reactive alumina by calorimetry, thermogravimetry and other methods

Madej

Szczerba

2015

J Therm Anal Calorim

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The reactivities of hydratable alumina, calcium zirconium aluminate and their binary mixtures were investigated by calorimetric method, X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), differential thermal/thermogravimetric analysis (DTA-TG) and scanning electron microscope observations. The rate of heat evolution illustrates only one distinct exothermic peak in the mixtures containing calcium zirconium aluminate which corresponds the subsequent precipitation of hydrated material mainly in the form of amorphous CaO-Al 2 O 3 -H 2 O phases and crystalline C 4 AH 19 occurs simultaneously after wetting of Ca 7 ZrAl 6 O 18 grains. Nevertheless, coexistence of both unstable calcium aluminate hydrates (CAH 10 , C 2 AH 8 , C 4 AH 19 ) and thermodynamically more stable C 3 AH 6 detected by FT-IR and DTA-TG in the paste cured at 20°C may have originated in the thermally induced partial conversion reaction due to the considerable amount of heat generated by the Ca 7 ZrAl 6 O 18 hydration. It is also found that curing temperature affected the hydration products formed in the hydration products of both Ca 7-ZrAl 6 O 18 and Ca 7 ZrAl 6 O 18 /Al 2 O 3 blends. Reactive alumina influences the hydration behavior of Ca 7 ZrAl 6 O 18 facilitating the nucleation and growth of hydration products, causes characteristic changes in the microstructure of hardened blended pastes and favors recrystallization of dehydrated calcium aluminates.

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Studies on thermal dehydration of the hydrated Ca7ZrAl6O18 at different water–solid ratios cured at 60 °C

Cited by 15 publications

References 16 publications

PREPARATION OF Al₂O₃-CaAl₁₂O₁₉-ZrO₂ COMPOSITE CERAMIC MATERIAL BY THE HYDRATION AND SINTERING OF Ca₇ZrAl₆O₁₈-REACTIVE ALUMINA MIXTURE

PREPARATION OF Al₂O₃-CaAl₁₂O₁₉-ZrO₂ COMPOSITE CERAMIC MATERIAL BY THE HYDRATION AND SINTERING OF Ca₇ZrAl₆O₁₈-REACTIVE ALUMINA MIXTURE

Hydration, carbonation and thermal stability of hydrates in Ca7−xSrxZrAl6O18 cement

Study of the hydration of calcium zirconium aluminate (Ca7ZrAl6O18) blended with reactive alumina by calorimetry, thermogravimetry and other methods

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