A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Belite hydration at high temperature and pressure by in situ synchrotron powder diffraction
https://orcid.org/0000-0001-6877-7375
https://orcid.org/0000-0001-7708-3578
Highlights Hydration at 180 bars and of 160 °C is reported by in situ synchrotron diffraction. Alite (single phase and in mixtures) reacts very fast reaching 85–90% DoH at 2 h. Belite hydration rate is strongly accelerated by alite presence. 20 wt%-alite and 80 wt%-belite did not yield Jaffeite and lower amount of α-C2SH. Belite DoH reached 62% at 14 h for an industrially produced belite cement.
Abstract Portland cements are currently used as Oil‐Well‐Cements for the sheath between the metal casing and the borehole. At high pressures and temperatures, the resulting C–S–H gel(s) is partly unstable and it can react to give different crystalline phases and changing microstructure which increases porosity. It is known that the addition of silica-rich materials to Portland cements, used to decrease the overall Ca/Si molar ratio, avoids/minimises the early strength retrogression experienced by neat cement slurries. Alternatively, belite-rich cement could be used but belite reactivity in these conditions is largely unexplored. Here, belite-rich mixtures have been quantitatively studied at 180 bars and of 160 °C by in situ synchrotron powder diffraction using a tailored-designed spinning capillary cell. For model alite/belite mixtures, alite strongly accelerates belite hydration in these conditions. At 10 h of hydration, β-C2S shows a reaction degree of 30 and 80% for 20 wt%C3S-80 wt%C2S and 50 wt%C3S-50 wt%C2S mixtures, respectively. Furthermore, the 50 wt%C3S mixture hydrates yielding significant amounts of Jaffeite and α-C2SH and the 20 wt%C3S mixture gave no Jaffeite and much lower amount of α-C2SH. Finally, a belite cement has also been hydrated in these conditions and the reaction degree of belite was 50% at 10 h. The hydration of this cement did not yield Jaffeite neither α-C2SH in the studied experimental conditions.
Belite hydration at high temperature and pressure by in situ synchrotron powder diffraction
https://orcid.org/0000-0001-6877-7375
https://orcid.org/0000-0001-7708-3578
Highlights Hydration at 180 bars and of 160 °C is reported by in situ synchrotron diffraction. Alite (single phase and in mixtures) reacts very fast reaching 85–90% DoH at 2 h. Belite hydration rate is strongly accelerated by alite presence. 20 wt%-alite and 80 wt%-belite did not yield Jaffeite and lower amount of α-C2SH. Belite DoH reached 62% at 14 h for an industrially produced belite cement.
Abstract Portland cements are currently used as Oil‐Well‐Cements for the sheath between the metal casing and the borehole. At high pressures and temperatures, the resulting C–S–H gel(s) is partly unstable and it can react to give different crystalline phases and changing microstructure which increases porosity. It is known that the addition of silica-rich materials to Portland cements, used to decrease the overall Ca/Si molar ratio, avoids/minimises the early strength retrogression experienced by neat cement slurries. Alternatively, belite-rich cement could be used but belite reactivity in these conditions is largely unexplored. Here, belite-rich mixtures have been quantitatively studied at 180 bars and of 160 °C by in situ synchrotron powder diffraction using a tailored-designed spinning capillary cell. For model alite/belite mixtures, alite strongly accelerates belite hydration in these conditions. At 10 h of hydration, β-C2S shows a reaction degree of 30 and 80% for 20 wt%C3S-80 wt%C2S and 50 wt%C3S-50 wt%C2S mixtures, respectively. Furthermore, the 50 wt%C3S mixture hydrates yielding significant amounts of Jaffeite and α-C2SH and the 20 wt%C3S mixture gave no Jaffeite and much lower amount of α-C2SH. Finally, a belite cement has also been hydrated in these conditions and the reaction degree of belite was 50% at 10 h. The hydration of this cement did not yield Jaffeite neither α-C2SH in the studied experimental conditions.
Belite hydration at high temperature and pressure by in situ synchrotron powder diffraction
https://orcid.org/0000-0001-6877-7375
https://orcid.org/0000-0001-7708-3578
Highlights Hydration at 180 bars and of 160 °C is reported by in situ synchrotron diffraction. Alite (single phase and in mixtures) reacts very fast reaching 85–90% DoH at 2 h. Belite hydration rate is strongly accelerated by alite presence. 20 wt%-alite and 80 wt%-belite did not yield Jaffeite and lower amount of α-C2SH. Belite DoH reached 62% at 14 h for an industrially produced belite cement.
Abstract Portland cements are currently used as Oil‐Well‐Cements for the sheath between the metal casing and the borehole. At high pressures and temperatures, the resulting C–S–H gel(s) is partly unstable and it can react to give different crystalline phases and changing microstructure which increases porosity. It is known that the addition of silica-rich materials to Portland cements, used to decrease the overall Ca/Si molar ratio, avoids/minimises the early strength retrogression experienced by neat cement slurries. Alternatively, belite-rich cement could be used but belite reactivity in these conditions is largely unexplored. Here, belite-rich mixtures have been quantitatively studied at 180 bars and of 160 °C by in situ synchrotron powder diffraction using a tailored-designed spinning capillary cell. For model alite/belite mixtures, alite strongly accelerates belite hydration in these conditions. At 10 h of hydration, β-C2S shows a reaction degree of 30 and 80% for 20 wt%C3S-80 wt%C2S and 50 wt%C3S-50 wt%C2S mixtures, respectively. Furthermore, the 50 wt%C3S mixture hydrates yielding significant amounts of Jaffeite and α-C2SH and the 20 wt%C3S mixture gave no Jaffeite and much lower amount of α-C2SH. Finally, a belite cement has also been hydrated in these conditions and the reaction degree of belite was 50% at 10 h. The hydration of this cement did not yield Jaffeite neither α-C2SH in the studied experimental conditions.
Belite hydration at high temperature and pressure by in situ synchrotron powder diffraction
Morales-Cantero, Alejandro (author) / De la Torre, Angeles G. (author) / Cuesta, Ana (author) / Fraga-Lopez, Edmundo (author) / Shirani, Shiva (author) / Aranda, Miguel A.G. (author)
2020-09-03
Article (Journal)
Electronic Resource
English
Crystal Structure and Hydration of Belite
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