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Alteration of compacted GMZ bentonite by infiltration of alkaline solution

Published online by Cambridge University Press:  02 January 2018

Chen Bao ,
Guo Jiaxing  and
Zhang Huixin
Chen Bao*
Affiliation:
Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China
Guo Jiaxing
Affiliation:
Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China
Zhang Huixin
Affiliation:
Shanghai Construction Design & Research Institute Co., Ltd., Shanghai 200050, China
*
*E-mail: chenbao@tongji.edu.cn
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Abstract

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Concepts for geological disposal of high-level radioactive waste usually include bentonite buffer materials. Numerous studies have been performed with most usingWyoming bentonite. Gaomiaozi (GMZ) bentonite has been selected as a potential buffer/backfill material for the deep geological repository of high-level radioactive waste in China. In this context, the highly alkaline environment induced by cementitious materials in the repository is likely to alter montmorillonite, the main clay mineral in GMZ bentonite. This alteration may result in deterioration of the physical and/or chemical properties of the buffer material. To acquire quantitative data which would allow us to assess the dissolution of montmorillonite and changes in the diffusivity of hydroxide ions as well as their effects on the swelling pressure and permeability of the compacted GMZ bentonite, an experimental study was conducted under highly alkaline (NaOH solutions with various pH values were used), simulated groundwater conditions. The GMZ bentonite also contains cristobalite which may also have been dissolved. The microstructure of the compacted bentonite samples after the experiments was determined by mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDX) was carried out to identify mineralogical changes. At pH >13, the permeability of specimens increased significantly; the swelling potential decreased with increasing pH. Furthermore, the pore volume and pore size of GMZ bentonite changed when exposed to alkaline solution, resulting in an increase in porosity and permeability. The main alteration mechanisms of compacted GMZ bentonite undergoing infiltration by highly alkaline solution are likely to be dissolution and modifications in terms of the microstructure and mineralogy.

Keywords

GMZ bentonitehighly alkaline solutionswelling pressurepermeabilitymicrostructure

Information

Type
Research Article
Information
Clay Minerals , Volume 51 , Issue 2 , May 2016 , pp. 237 - 247
Creative Commons
Creative Common License - CCCreative Common License - BY
Copyright © The Mineralogical Society of Great Britain and Ireland 2016 This is an Open Access article, distributed under the terms of the Creative Commons Attribution license. (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2016

References

Anderson, K., Allard, B. & Bengtsson, M. (1989) Chemical composition of cement pore solutions. Cement and Concrete Research, 19, 327–332.10.1016/0008-8846(89)90022-7CrossRefGoogle Scholar
Berner, U.R. (1992) Evolution of pore-water chemistry during degradation of cement in a radioactive waste repository environment. Waste Management, 12, 201–219.10.1016/0956-053X(92)90049-OGoogle Scholar
Cuisinier, O., Masrouri, F. & Pelletier, M. (2008) Microstructure of a compacted soil submitted to an alkaline plume. Applied Clay Science, 40, 159–170.10.1016/j.clay.2007.07.005Google Scholar
Deneele, D., Cuisinier, O. & Hallaire, V. (2010) Mico structural evolution and physico-chemical behavior of compacted clayey soil submitted to an alkaline plume. Journal of Rock Mechanics and Geotechnical Engineering, 2, 169–177.10.3724/SP.J.1235.2010.00169CrossRefGoogle Scholar
Glasser, F.P. & McCulloch, C. (1988) Characterization of radioactive waste forms. Commission of the European Communities, Luxembourg, pp. 107—125.Google Scholar
Guo, Y.H., Wang, J. & Lu, C.H. (2005) Chemical characteristics of groundwater and water-rock interaction: modeling of Yemaquan preselected area for China's high level radioactive waste repository. Earth Science Frontiers, 12, 117–123.(in Chinese).Google Scholar
Herbert, H., Kasbohm, J. & Sprenger, H. (2008) Swelling pressures of MX-80 bentonite in solutions of different ionic strength. Physics and Chemistry of the Earth, A/ B/C, 33, 327–342.10.1016/j.pce.2008.10.005Google Scholar
Karnland, O., Olsson, S. & Nilsson, U. (2007) Experimentally determined swelling pressures and geochemical interactions of compacted Wyoming bentonite with highly alkaline solutions. Physics and Chemistry of the Earth, 32, 275–286.10.1016/j.pce.2006.01.012Google Scholar
Lehikoinen, J., Carlsson, T. & Muurinen, A. (1996) Evaluation of factors affecting diffusion in compacted bentonite. Materials Research Society Proceedings. Materials Research Society, Pittsburgh, USA, pp. 675–682.Google Scholar
Liu, Y.M. & Wen, Z.J. (2003) Study on clay materials used in a high level radioactive waste repository. Journal of Mineralogy and Petrology, 23, 42–45.(in Chinese).Google Scholar
Nakayama, S., Sakamoto, Y. & Yamaguchi, T. (2004) Dissolution of montmorillonite in compacted bentonite by highly alkaline aqueous solutions and diffusivity of hydroxide ions. Applied Clay Science, 27, 53–65.10.1016/j.clay.2003.12.023Google Scholar
Qian, L.X. (2007) A fundamental study of GMZ bentonite as buffer material in deep geological disposal for high-level radioactive waste. PhD thesis, Tongji University, China (in Chinese).Google Scholar
Ramírez, S., Cuevas, J. & Vigil, R. (2002) Hydrothermal alteration of ‘La Serrata’ bentonite (Almería Spain) by alkaline solutions. Applied Clay Science, 21, 257–269.10.1016/S0169-1317(02)00087-XGoogle Scholar
Ramírez, S., Vieillarda, P. & Bouchetc, A. (2005) Alteration of the Callovo-Oxfordian clay from Meuse-Haute Marne underground laboratory (France) by alkaline solution. I. A XRD and CEC study. Applied Geochemistry, 20, 89–99.10.1016/j.apgeochem.2004.03.009Google Scholar
Read, D., Glasser, F.P. & Ayora, C. (2001) Mineralogical and micro structural changes accompanying the interaction of Boom Clay with ordinary Portland cement. Advances in Cement Research, 13, 175–183.10.1680/adcr.2001.13.4.175CrossRefGoogle Scholar
Sánchez, L., Cuevas, J. & Ramírez, S. (2006) Reaction kinetics of FEBEX bentonite in hyperalkaline conditions resembling the cement-bentonite interface. Applied Clay Science, 33, 125–141.10.1016/j.clay.2006.04.008Google Scholar
Savage, D., Noy, D. & Mihara, M. (2002) Modelling the interaction of bentonite with hyperalkaline fluids. Applied Geochemistry, 17, 207–223.10.1016/S0883-2927(01)00078-6Google Scholar
Savage, D., Walker, C. & Arthur, R. (2007) Alteration of bentonite by hyperalkaline fluids: A review of the role of secondary minerals. Physics and Chemistry of the Earth, 32, 287–297.10.1016/j.pce.2005.08.048Google Scholar
Vigil, R., Cuevas, J., Ramírez, S. (2001) Zeolite formation during the alkaline reaction of bentonite. European Journal of Mineralogy, 13, 635–644.Google Scholar
Villar, M.V. (2006) Infiltration tests on a granite/bentonite mixture: Influence of water salinity. Applied Clay Science, 31, 96–109.10.1016/j.clay.2005.07.007Google Scholar
Wen, Z.J. (2006) Physical property of China's buffer material for high-level radioactive waste repositories. Chinese Journal of Rock Mechanics and Engineering, 25, 794–800.Google Scholar
Yamaguchi, T., Sakamoto, Y. & Akai, M. (2007) Experimental and modeling study on long-term alteration of compacted bentonite with alkaline groundwater. Physics and Chemistry of the Earth, 32, 298–310.10.1016/j.pce.2005.10.003CrossRefGoogle Scholar
Ye, W.M., Qian, L.X. & Chen, B. (2009) Characteristics of micro-structure of densely compacted Gaomiaozi bentonite. Journal of Tongji University (Natural Science), 37, 31–35 (in Chinese).Google Scholar
Ye, W.M., Chen, Y.G. & Chen, B. (2010) Advances on the knowledge of the buffer/backfill properties of heavily-compacted GMZ bentonite. Engineering Geology, 116, 12–20.10.1016/j.enggeo.2010.06.002Google Scholar