The Atomic-Level Structure of Cementitious Calcium Aluminate Silicate Hydrate Determined by NMR
We review our recent paper which resolves the long-standing dilemma of the location and nature of the six-fold coordinated aluminum in calcium aluminate silicate hydrate (C-A-S-H) samples. First principles calculations predict that at high Ca:Si and H2O ratios, aluminum is incorporated into the brid...
| Main Authors: | , |
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| Format: | Article |
| Language: | deu |
| Published: |
Swiss Chemical Society
2021-04-01
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| Series: | CHIMIA |
| Subjects: | |
| Online Access: | https://www.ingentaconnect.com/contentone/scs/chimia/2021/00000075/00000004/art00006 |
| Summary: | We review our recent paper which resolves the long-standing dilemma of the location and nature of the six-fold coordinated aluminum in calcium aluminate silicate hydrate (C-A-S-H) samples. First principles calculations predict that at high Ca:Si and H2O ratios, aluminum is incorporated into the bridging sites of the linear silicate chains and that the stable coordination number is six. We confirm this hypothesis experimentally by one- and two-dimensional dynamic nuclear polarization enhanced 27 Al and 29 Si solid-state NMR experiments in which we correlate the distinctive six-fold coordinated aluminum NMR signal at 5 ppm to 29 Si NMR signals from silicates in C-A-S-H. |
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| ISSN: | 0009-4293 2673-2424 |