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The Atomic-Level Structure of Cementitious Calcium Aluminate Silicate Hydrate Determined by NMR
- Source :
- CHIMIA, Vol 75, Iss 4, Pp 272-275 (2021)
- Publication Year :
- 2021
-
Abstract
- 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.
- Subjects :
- portland cements
metakaolin
spectroscopy
six-fold coordinated alumnium
Materials science
Coordination number
Aluminate
si-29
al-27
chemistry.chemical_element
Calcium
c-s-h
chemistry.chemical_compound
mas
enhanced nmr
Aluminium
dynamic nuclear-polarization
dnp
solid-state nmr
dnp.mas
Polarization (electrochemistry)
c-a-s-h
QD1-999
six-fold coordinated aluminum
General Medicine
General Chemistry
gels
Silicate
al
Chemistry
chemistry
Physical chemistry
Cementitious
Hydrate
Subjects
Details
- ISSN :
- 00094293
- Volume :
- 75
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- Chimia
- Accession number :
- edsair.doi.dedup.....89f3ca4a85b2df303c3dc2164d7223d0