Studies using 27Al MAS NMR of AFm and AFt phases and the formation of Friedel's salt
| Autor: | John A. Chudek, R. Talero, R. Lannegrand, Geoffrey Hunter, Donald E. Macphee, S. N. Scrimgeour, Martyn Jones |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Cement
Materials science Silica fume Mineralogy Slag Building and Construction Chloride law.invention Portland cement chemistry.chemical_compound Friedel's salt Chemical engineering chemistry law visual_art Fly ash medicine visual_art.visual_art_medium General Materials Science Metakaolin medicine.drug |
| Zdroj: | Cement and Concrete Research. 33:177-182 |
| ISSN: | 0008-8846 |
| Popis: | This paper describes the application of the magic angle spinning (MAS) NMR spectroscopy to study the chemical environment of 27Al-bearing phases in Portland cement-based concrete. A specific methodology is described that allows reliable spectra to be determined for combinations of different types of cements and fillers (in this case, Portland cement, fly ash, slag, silica fume, metakaolin and limestone filler). As well as the study of ‘molecular structure’ of cement matrix, the paper reviews the mechanism of Friedel's salt formation in cement systems. Mechanisms based on ion exchange of chloride for hydroxide in hydroxy-AFm and on chloride absorption on formation are discussed. Finally, the nature of the chloride/hydrate binding phenomena are described to provide a reasonable robust and fundamental picture of the role different cements can play in the provision of overall concrete durability to chloride ingress from a chemical perspective. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect