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Cohesive Strength Improvement Mechanism Of Kaolinite Near the Anode During Electroosmotic Chemical Treatment

Published online by Cambridge University Press:  01 January 2024

Yuan-Shiang Lin ,
Chang-Yu Ou  and
Shao-Chi Chien
Yuan-Shiang Lin
Affiliation:
Department of Civil and Construction Engineering, National Taiwan University of Science and Technology, No. 43, Sec. 4, Keelung Rd., Taipei City 10607, Taiwan
Chang-Yu Ou*
Affiliation:
Department of Civil and Construction Engineering, National Taiwan University of Science and Technology, No. 43, Sec. 4, Keelung Rd., Taipei City 10607, Taiwan
Shao-Chi Chien
Affiliation:
Aletheis University, No.32, Zhenli St., Danshui Dist., New Taipei City 25103, Taiwan
*
*E-mail address of corresponding author: [email protected]
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Abstract

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Injection of CaCl2 and Na2SiO3 solutions into clay suspensions during electroosmosis often improves the cohesive strength of clays near the anode and cathode, whereas the cohesive strength of clays between the electrodes remains weak. Although the main improvement mechanism for the cohesive strength of clays near the cathode was demonstrated to be a pozzolanic reaction (formation of calcium silicate hydrate cement), the mechanism of improved cohesive strength near the anode is still not understood. The objective of the present study was to investigate the mechanism for the improvement of cohesive strength near the anode and, thus, make it possible to determine a way to enhance the range in improvement using kaolinite as the test clay. The test was performed by first injecting CaCl2 solution during electroosmosis until the optimum volume of CaCl2 was attained. This was followed by treatment with Na2SiO3 solution for different lengths of time. The results indicate that the anode region after treatment was acidic (pH = 4) because the electrolysis of water causes acidification near the anode. As Na2SiO3 solution was injected through the anode, the mechanism of cohesive strength improvement of the treated clay near the anode was attributed to the silicic acid polymerization effect provided by the Na2SiO3 solution. The silicic acid may link the clay particles together to form a gel network in a low pH environment. The clay gel network structure developed rigidity as the water content was reduced. In addition, as the volume of injected Na2SiO3 solution was increased, the cohesive strength near the anode also increased.

Keywords

Anode AreaElectrokinetic TreatmentElectroosmotic Chemical TreatmentPolymerization
Type
Article
Information
Clays and Clay Minerals , Volume 66 , Issue 5 , October 2018 , pp. 438 - 448
Copyright
Copyright © Clay Minerals Society 2018

References

Abdullah, W.S. and Al-Abadi, A.M. (2010) Cationic–electrokinetic improvement of an expansive soil. Applied Clay Science, 47, 343–350.CrossRefGoogle Scholar
Ahmad, T.S.A. (2012) Electrokinetic Stabilisation of Soft Clay. PhD thesis, School of Civil Engineering, University of Birmingham, UK.Google Scholar
Asavadorndeja, P. and Glawe, U. (2005) Electrokinetic strengthening of soft clay using the anode depolarization method. Bulletin of Engineering Geology and the Environment, 64, 237–245.CrossRefGoogle Scholar
ASTM D2216-10 (2010) Standard Test Methods for Laboratory Determination of Water (moisture) Content of Soil and Rock by Mass. .Google Scholar
ASTM D4972-13 (2013) Standard Test Methods for pH of Soils. .Google Scholar
ASTM D5778-12 (2012) Standard Test Method for Performing Electronic Friction Cone and Piezocone Penetration Testing of Soils. .Google Scholar
Barker, J.E., Rogers, C.D.F., Boardman, D.I., and Peterson, J. (2004) Electrokinetic stabilization: An overview and case study. Ground Improvement, 8, 47–58.CrossRefGoogle Scholar
Chang, H.W., Krishna, P.G., Chien, S.C., Ou, C.Y., and Wang, M.K. (2010) Electro-osmotic chemical treatments: Effects of Ca2+ concentration on the mechanical strength and pH of kaolin. Clays and Clay Minerals, 58, 154–163.CrossRefGoogle Scholar
Davidovits, J. (2008) MAS-NMR spectroscopy. Pp. 70–78 in: Geopolymer Chemistry and Applications. 4th edition, Institute Géopolymère, Saint-Quentin, France.Google Scholar
Iler, R.K. (1979) The Chemistry of Silica: Solubility, Polymerization, Colloid and Surface Properties and Biochemistry of Silica. Wiley Interscience, New York.Google Scholar
ISO 11466 (1995) Soil quality–Extraction of trace elements soluble in aqua regia. : std: iso: 11466: ed-1: v1: en.Google Scholar
Liaki, C., Rogers, C.D.F., and Boardman, D.I. (2007) Physicochemical study of clay soil using inert and steel electrodes. Proceedings of 6th International Symposium on Electrokinetic Remediation, Vigo, Spain, 12th–15th June.Google Scholar
Liaki, C., Rogers, C.D.F., and Boardman, D.I. (2008) Physico-chemical effects on uncontaminated kaolinite due to electrokinetic treatment using inert electrodes. Journal of Environmental Health and Science - Part A, 43, 810–822.CrossRefGoogle Scholar
Liaki, C., Rogers, C.D.F., and Boardman, D.I. (2010) Physico-chemical effects on clay due to electromigration using stainless steel electrodes, Journal of Applied Electrochemistry, 40, 1225–1237.CrossRefGoogle Scholar
Lin, Y.S., Chien, S.C., and Ou, C.Y. (2017) On the improvement through the middle area of kaolinite with electroosmotic chemical treatment. Journal of GeoEngineering, 12, 167–173.Google Scholar
Mitchell, J.K. and Soga, K. (2005) Fundamentals of Soil Behavior. 3rd Edition, John Wiley and Sons, New York.Google Scholar
Mosavat, N., Oh, E., and Chai, G. (2013) Laboratory assessment of kaolinite and bentonite under chemical–electrokinetic treatment. Journal of Civil and Environment Engineering, 3, 1–7.Google Scholar
Nordin, N.S., Ahmad, T.S.A., and Abdul, K.A. (2013) Stabilisation of soft soil using electrokinetic stabilisation method. International Journal of Zero Waste Generation, 1, 5–12Google Scholar
Otsuki, N., Yodsudjai, W., and Nishida, T. (2007) Feasibility study on soil improvement using electrochemical technique. Construction and Building Materials, 21, 1046–1051.CrossRefGoogle Scholar
Ou, C.Y., Chien, S.C., and Wang, Y.G. (2009) On the enhancement of electroosmotic soil improvement by the injection of saline solutions. Applied Clay Science, 44, 130–136.CrossRefGoogle Scholar
Ou, C.Y., Chien, S.C., and Lee, TY. (2013) Development of a suitable operation procedure for electroosmotic chemical soil improvement. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 39, 993–1000.CrossRefGoogle Scholar
Ou, C.Y., Chien, S.C., Yang, C.C., and Chen, C.T. (2015) Mechanism of soil cementation for electroosmotic chemical treatment. Applied Clay Science, 104, 135–142.CrossRefGoogle Scholar
Rogers, C.D.F., Liaki, C., and Boardman, D.I. (2003) Advances in the engineering of lime stabilised clay soils. International Conference on Problematic Soils, Nottingham, UK.Google Scholar