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Simultaneous Transport of Chloride and Calcium Ions in Hydrated Cement Systems
Title: | Simultaneous Transport of Chloride and Calcium Ions in Hydrated Cement Systems |
Authors: | Sugiyama, Takafumi Browse this author →KAKEN DB | Ritthichauy, Worapatt Browse this author | Tsuji, Yukikazu Browse this author |
Issue Date: | Oct-2004 |
Journal Title: | Journal of Advanced Concrete Technology |
Volume: | 1 |
Issue: | 2 |
Start Page: | 127 |
End Page: | 138 |
Publisher DOI: | 10.3151/jact.1.127 |
Abstract: | This paper presents a new method for numerically calculating the concentration profiles of both solid calcium and total chloride ions (Cl−) in concrete in contact with 3% (0.5 mol/l) sodium chloride (NaCl) solution. Since the diffusion of ions present in the pore solution is a primary controlling factor, the application of mutual diffusion coefficients of corresponding ions that are influenced by the concentration of other coexisting ions is proposed. The method of calculation is based on the generalized form of Fick's First Law suggested by Onsager, which is composed of the Onsager phenomenological coefficient and the thermodynamic force between ions, which occurs according to the gradient of electrochemical potential in a multicomponent concentrated solution for the pore solution. In addition, the chemical equilibrium for Ca(OH)2 dissolution and C-S-H decalcification are also modeled and coupled with diffusion. Increased porosity due to dissolved Ca2+ and a chloride binding isotherm are taken into consideration. The concentration profiles of solid calcium and the presence of Friedel's salt in mortar specimens are experimentally identified by the X-ray diffraction method (XRD) and the thermal analysis (TG/DTA) as well as the total chloride profile using an acid extraction method after three years of exposure to 0.5 mol/l NaCl solution. This experimental result verifies the calculation result. |
Type: | article |
URI: | http://hdl.handle.net/2115/54944 |
Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 杉山 隆文
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