Quantification of the degree of reaction of fly ash
- Empa, Swiss Federal Laboratory for Materials Testing and Research, Laboratory for Concrete and Construction Chemistry, 8600 Duebendorf (Switzerland)
The quantification of the fly ash (FA) in FA blended cements is an important parameter to understand the effect of the fly ash on the hydration of OPC and on the microstructural development. The FA reaction in two different blended OPC-FA systems was studied using a selective dissolution technique based on EDTA/NaOH, diluted NaOH solution, the portlandite content and by backscattered electron image analysis. The amount of FA determined by selective dissolution using EDTA/NaOH is found to be associated with a significant possible error as different assumptions lead to large differences in the estimate of FA reacted. In addition, at longer hydration times, the reaction of the FA is underestimated by this method due to the presence of non-dissolved hydrates and MgO rich particles. The dissolution of FA in diluted NaOH solution agreed during the first days well with the dissolution as observed by image analysis. At 28 days and longer, the formation of hydrates in the diluted solutions leads to an underestimation. Image analysis appears to give consistent results and to be most reliable technique studied.
- OSTI ID:
- 21483635
- Journal Information:
- Cement and Concrete Research, Vol. 40, Issue 11; Other Information: DOI: 10.1016/j.cemconres.2010.07.004; PII: S0008-8846(10)00164-X; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0008-8846
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CEMENTS
DISSOLUTION
EDTA
FLY ASH
HYDRATES
HYDRATION
IMAGE PROCESSING
MAGNESIUM OXIDES
MICROSTRUCTURE
SCANNING ELECTRON MICROSCOPY
SODIUM HYDROXIDES
AEROSOL WASTES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
AMINO ACIDS
ASHES
BUILDING MATERIALS
CARBOXYLIC ACIDS
CHALCOGENIDES
CHELATING AGENTS
COMBUSTION PRODUCTS
ELECTRON MICROSCOPY
HYDROGEN COMPOUNDS
HYDROXIDES
MAGNESIUM COMPOUNDS
MATERIALS
MICROSCOPY
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PROCESSING
RESIDUES
SODIUM COMPOUNDS
SOLVATION
WASTES