Effects of porosity on leaching of Ca from hardened ordinary Portland cement paste
- Taiheiyo Consultant Co. Ltd., 2-4-2, Osaku, Sakura-City, Chiba 285-8655 (Japan)
- Central Research Institute of Electric Power Industry, 1646, Abiko, Abiko-City, Chiba 270-1194 (Japan)
- Department of Quantum Engineering and Systems Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)
- Institute of Environmental Studies, Graduate School of Frontier Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)
Aiming at evaluating the effects of porosity in hardened cement paste on dissolution phenomena, we prepared hardened ordinary Portland cement (OPC), with variation in pore volume, and then leached them in deionized water. It was found that the bulk density and pore volume were affected by the dissolution of portlandite. The larger the pore volume of the sample, the more rapidly portlandite is dissolved. An electron probe microanalysis (EPMA) performed on the cross-section of the solid phase showed the 'portlandite (CH) dissolution front'. As the leaching period became longer, the CH dissolution front shifted towards the inner part. In addition, the movement of the CH dissolution front was described by the diffusion model, with consideration of the dissolution of portlandite. It was concluded that the transport of leached constituents is diffusion controlled, and the major leached constituents of hardened OPC are portlandite and C-S-H gel. Large pore, which was generated associated with the leaching of portlandite, was considered significantly to affect the diffusion of leached constituents.
- OSTI ID:
- 20706235
- Journal Information:
- Cement and Concrete Research, Vol. 35, Issue 9; Other Information: DOI: 10.1016/j.cemconres.2004.06.034; PII: S0008-8846(04)00287-X; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0008-8846
- Country of Publication:
- United States
- Language:
- English
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