Retention of alkali ions by hydrated low-pH cements: Mechanism and Na+/K+ selectivity

被引：104
|
作者：
Bach, T. T. H. [1 ]
Chabas, E. [1 ]
Pochard, I. [2 ]
Coumes, C. Cau Dit [1 ]
Haas, J. [2 ]
Frizon, F. [1 ]
Nonat, A. [2 ]
机构：
[1] Commissariat Energie Atom & Energies Alternat, DEN MAR DTCD SPDE, F-30207 Bagnols Sur Ceze, France
[2] Univ Bourgogne, CNRS, UMR 6303, ICB, F-21078 Dijon, France
来源：
CEMENT AND CONCRETE RESEARCH | 2013年 / 51卷
关键词：
Low-pH cement; Alkalis (D); C-S-H (B); X-ray diffraction (B); C-S-H; LOW-HEAT; SURFACE; SUSPENSIONS; RESISTANCE;
D O I：
10.1016/j.cemconres.2013.04.010
中图分类号：
TU [建筑科学];
学科分类号：
0813 ;
摘要：
Low-pH cements, also referred to as low-alkalinity cements, can be designed by replacing significant amounts of Portland cement by pozzolanic materials. Their pore solution is characterized by a pH near 11, and an alkali concentration much lower than that of Portland cement. This work investigates the retention of sodium and potassium by a hydrated low-pH cement comprising 60% Portland cement and 40% silica fume. It is shown that sorption of potassium is higher than that of sodium and mainly results from counterion charge balancing of the C-S-H negative surface charge. To explain the greater retention of potassium compared to sodium, it is postulated that potassium, unlike sodium, may enter the interlayer of C-S-H to compensate the negative charges in the interlayer, in addition to the external surfaces. This assumption is supported by structural characterization of C-S-H using X-ray diffraction. (c) 2013 Elsevier Ltd. All rights reserved.
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页码：14 / 21
页数：8
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