Clays and Clay Minerals

, Volume 58, Issue 3, pp 399–414 | Cite as

Porosity Evolution of Free and Confined Bentonites during Interlayer Hydration

  • William J. LikosEmail author
  • Alexandra Wayllace


Methods for predicting the volume change and swelling-pressure behavior of expansive clays require detailed understanding of coupled interactions between clay microstructure and macrostructure under hydraulic, thermal, and mechanical loads. In this study a suite of water-vapor sorption experiments was conducted using compacted bentonites hydrated in controlled relative humidity (RH) environments maintained under free and constrained volume-change boundary conditions. Emphasis was placed on examining the influences of compaction and predominant exchange cation on the water uptake, volume change, and swelling pressure response. Densely compacted specimens exhibited greater volume changes under free swelling conditions and greater swelling pressures under fully confined conditions. Water uptake, volume change, and swelling pressure were all more significant for Colorado (Ca2+/Mg2+) bentonite than forWyoming (Na+) bentonite. Plastic yielding, evident as a peak in the relationship between swelling pressure and RH, was more evident and occurred at lower RH for the Colorado bentonite. This observation was interpreted to reflect the limited capacity for interlayer swelling in Ca2+/Mg2+ bentonites and corresponding structural collapse induced by the onset of water uptake in larger intra-aggregate and inter-aggregate pores. A semi-quantitative model for the evolution of clay microstructure resulting from interlayer hydration was considered to attribute the experimental observations to differences in the efficiency with which transitions in basal spacing translate to bulk volume changes and swelling pressure. Results provide additional insight and experimental evidence to more effectively model the mechanical behavior of compacted bentonites used as buffer or barrier materials in waste repository applications.

Key Words

Bentonite Dehydration Hydration Interlayer Swelling Smectite Sorption 


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  1. Al-Mukhtar, M., Qi, Y., Alcover, J.F., and Bergaya, F. (1999) Oedometric and water-retention behavior of highly compacted unsaturated smectites. Canadian Geotechnical Journal, 36, 675–684.Google Scholar
  2. Alonso, E.E., Vaunat, J., and Gens, A. (1999) Modeling the mechanical behavior of expansive clays. Engineering Geology, 54, 173–183.Google Scholar
  3. ASTM (2000) ASTM D4318-05 Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils, ASTM International, 4.08, West Conshohocken, Pennsylvania, USA.Google Scholar
  4. Aylmore, L.A.G. and Quirk, J.P. (1971) Domains and quasicrystalline regions in clay systems. Soil Science Society of America Proceedings, 35, 652–654.Google Scholar
  5. Berend, I., Cases, J., Francois, M., Uriot, J., Michot, L., Maison, A., and Thomas, F. (1995) Mechanism of adsorption and desorption of water vapor by homoionic montmorillonites. Clays and Clay Minerals, 43, 324–336.Google Scholar
  6. Bernier, F., Volckaert, G., Alonso, E., and Villar, M. (1997) Suction-controlled experiments on Boom clay. Engineering Geology, 47, 325–338.Google Scholar
  7. Caballero, E., Jimenez de Cisneros, C., and Linares, J. (2004) Physicochemical properties of bentonite: effect of the exchangeable cations. Pp. 40–47 in: FEBEX II Project. THG Laboratory Experiments (T. Missana, editor). Publicacion Tecnica ENRESA 09/2004, Madrid.Google Scholar
  8. Cases, J.M., Berend, I., Besson, G., Francois, M., Uriot, J.P., Thomas, F., and Poirier, J.E. (1992) Mechanism of adsorption and desorption of water vapor by homoionic montmorillonite. I. The sodium exchanged form. Langmuir, 8, 2730–2739.Google Scholar
  9. Cases, J.M., Berend, I., Besson, G., Francois, M., Uriot, J.P., Michot, L., and Thomas, F. (1997) Mechanism of adsorption and desorption of water vapor by homoionic montmorillonite. III. The Mg2+, Ca2+, Sr2+, and Ba2+ exchanged forms. Clays and Clay Minerals, 45, 8–22.Google Scholar
  10. Chipera, S.J., Carey, J.W., and Bish, D.L. (1997) Controlled-humidity XRD analyses: Application to the study of smectite expansion/contraction. Pp. 713–721 in: Advances in X-ray Analysis, 36 (J.V. Gilfrich et al., editors). Plenum Press, New York.Google Scholar
  11. Cui, Y.J., Yahia-Aissa, M., and Delage, P. (2002) A model for the volume change behavior of heavily compacted swelling clays. Engineering Geology, 64, 233–250.Google Scholar
  12. Delage, P., Howat, M.D., and Cui, Y.J. (1998) The relationship between suction and swelling properties in a heavily compacted unsaturated clay. Engineering Geology, 50, 31–48.Google Scholar
  13. Del Pennino, U., Mazzega, E., and Valeri, S. (1981) Interlayer water and swelling properties of monoionic montmorillonites. Journal of Colloid and Interface Science, 84, 301.Google Scholar
  14. Devineau, K., Bihannic, I., Michot, L., Villiéras, F., Masrouri, F., Cuisinier, O., Fragneto, G., and Michau, N. (2006) In situ neutron diffraction analysis of the influence of geometric confinement on crystalline swelling of montmorillonite. Applied Clay Science, 31, 76–84.Google Scholar
  15. Dohrmann, R. and Kaufhold, S. (2009) Three new, quick CEC methods for determining the amounts of exchangeable calcium cations in calcareous clays. Clays and Clay Minerals 57, 338–352.Google Scholar
  16. Eberl, D.D., Drits, V.A., and Środoń, J. (1996) MUDMASTER; a program for calculating crystallite size distributions and strain from the shapes of X-ray diffraction peaks. US Geological Survey Open File Report 96-0171.Google Scholar
  17. Ferrage, E., Lanson, B., Sakharov, B.A., and Drits, V.A. (2005) Investigation of smectite hydration properties by modeling experimental X-ray diffraction patterns: Part I. Montmorillonite hydration properties. American Mineralogist, 90, 1358–1374.Google Scholar
  18. Fripiat, J.T., Jelli, A., Poncelet, G., and Andre, J. (1965) Thermodynamic properties and adsorbed water molecules and electrical conduction in montmorillonite and silicates. Journal of Physical Chemistry, 69, 2185–2197.Google Scholar
  19. Gens, A. and Alonso, E.E. (1992) A framework for the behavior of unsaturated expansive clays. Canadian Geotechnical Journal, 29, 1013–1032.Google Scholar
  20. Gillery, F.H. (1959) Adsorption-desorption characteristics of synthetic montmorillonoids in humid atmospheres. American Mineralogist, 44, 806.Google Scholar
  21. Hall, P.L. and Astill, D.M. (1989) Adsorption of water by homoionic exchange forms of Wyoming montmorillonite (SWy-1). Clays and Clay Minerals, 37, 355–363.Google Scholar
  22. Hashizume, H., Shimomura, S., Yamada, H., Fujita, T., Nakazawa, H., and Akutsu, O. (1996) X-ray diffraction system with controlled relative humidity and temperature. Powder Diffraction, 11, 288–289.Google Scholar
  23. Huang, W., Bassett, W.A., and Wu, T. (1994) Dehydration and hydration of montmorillonite at elevated temperatures and pressures monitored using synchrotron radiation. American Mineralogist, 79, 683–691.Google Scholar
  24. Katti, D.R. and Shanmugasundaram, V. (2001) Influence of swelling on the microstructure of expansive clays. Canadian Geotechnical Journal, 38, 175–182.Google Scholar
  25. Keren, R. and Shainberg, I. (1975) Water vapor isotherms and heat of immersion of Na/Ca-montmorillonite systems — I: Homoionic clay. Clays and Clay Minerals, 23, 193–200.Google Scholar
  26. Keren, R. and Shainberg, I. (1979) Water vapor isotherms and heat of immersion of Na/Ca-montmorillonite systems — II: Mixed Systems. Clays and Clay Minerals, 27, 145–151.Google Scholar
  27. Keren, R. and Shainberg, I. (1980) Water vapor isotherms and heat of immersion of Na/Ca-montmorillonite systems — III: Thermodynamics. Clays and Clay Minerals, 28, 204–210.Google Scholar
  28. Komine, H. and Ogata, N. (1994) Experimental study on swelling characteristics of compacted bentonite. Canadian Geotechnical Journal, 31, 478–490.Google Scholar
  29. Laird, D.A., Shang, C. and Thompson, M.L. (1995) Hysteresis in crystalline swelling of smectites. Journal of Colloid and Interface Science, 171, 240–245.Google Scholar
  30. Lambe, T.W. and Whitman, R.V. (1969) Soil Mechanics. Wiley, New York.Google Scholar
  31. Likos, W.J. (2004) Measurement of crystalline swelling in expansive clay. Geotechnical Testing Journal, 27, 540–546.Google Scholar
  32. Likos, W.J. and Lu, N. (2006) Pore-scale analysis of bulk volume change from crystalline swelling in Na+- and Ca2+-smectite. Clays and Clay Minerals, 54, 516–529.Google Scholar
  33. Lloret, A., Villar, M.V., Sanchez, M., Gens, A., Pintado, X., and Alonso, E.E. (2003) Mechanical behavior of heavily compacted bentonite under high suction changes. Géotechnique, 53, 27–40.Google Scholar
  34. Mooney, R.W., Keenan, A.G., and Wood, L.A. (1952) Adsorption of water vapor by montmorillonite. II. Effect of exchangeable ions and lattice swelling as measured by X-ray diffraction. Journal of the American Chemical Society, 74, 1371–1374.Google Scholar
  35. Moore, D.M. and Reynolds, R.C. (1997) X-ray Diffraction and the Identification and Analysis of Clay Minerals. Oxford University Press, New York.Google Scholar
  36. Noe, D.C., Higgins, J.D., and Olsen, H.W. (2007) Steeply dipping heaving bedrock, Colorado: Part 2 — Mineralogical and Engineering Properties. Environmental and Engineering Geoscience, XIII, 309–324.Google Scholar
  37. Norrish, K. (1954) The swelling of montmorillonite. Transactions of the Faraday Society, 18, 120–134.Google Scholar
  38. Ormerod, E.C. and Newman, A.C.D. (1983) Water sorption on Ca-saturated clays: II. Internal and external surfaces of montmorillonite. Clay Minerals, 18, 289–299.Google Scholar
  39. Pusch, R. (1982) Mineral-water interactions and their influence on the physical behavior of highly compacted Na bentonite. Canadian Geotechnical Journal, 19, 381–387.Google Scholar
  40. Pusch, R. (1994) Waste Disposal in Rock. Developments in Geotechnical Engineering, 76. Elsevier, Amsterdam, 490 pp.Google Scholar
  41. Romero, E. and Simms, P.H. (2008) Microstructure investigation in unsaturated soils: A review with special attention to contribution of mercury intrusion porosimetry and environmental scanning electron microscopy. Geotechnical and Geological Engineering, 26, 705–727.Google Scholar
  42. Saiyouri, N., Tessier, D., and Hicher, P.Y. (2004) Experimental study of swelling in unsaturated compacted clays. Clay Minerals, 39, 469–479.Google Scholar
  43. Sanchez, M., Gens, A., Guimames, L.N., and Olivella, S. (2005) A double structure generalized plasticity model for expansive materials. International Journal for Numerical and Analytical Methods in Geomechanics, 29, 751–787.Google Scholar
  44. Schanz, T. and S. Tripathy (2009) Swelling pressure of a divalent-rich bentonite: Diffuse double-layer theory revisited. Water Resources Research, 45, W00C12.Google Scholar
  45. Tessier, D. (1990) Behavior and microstructure of clay minerals. Pp. 387–415 in: Soil Colloids and their Associations in Aggregates (M.F. DeBoodt et al., editors). Plenum Press, New York.Google Scholar
  46. Tuller, M. and Or, D. (2003) Hydraulic functions for swelling soils: pore-scale considerations. Journal of Hydrology, 272, 50–71.Google Scholar
  47. USDA (2004) Soil Survey Laboratory Methods Manual, Soil Survey Investigations Report No. 42, R. Burt (editor). United States Department of Agriculture, method 4B1b, Version 4.0, 2004.Google Scholar
  48. Villar, M.V. (1999) Investigation of the behavior of bentonite by means of suction-controlled oedometer tests. Engineering Geology, 54, 67–73.Google Scholar
  49. Villar, M.V. (2007) Water retention of two natural compacted bentonites. Clays and Clay Minerals, 55, 311–322.Google Scholar
  50. Yahia-Aissa, M., Delage, P., and Cui, Y.J. (2001) Suction-water content relationship in swelling clays. Pp. 65–68 in: Clay Science for Engineering (K. Adachi and M. Kukue, editors). Balkema, Rotterdam.Google Scholar
  51. Young, J.F. (1967) Humidity control in the laboratory using salt solutions — A review. Journal of Applied Chemistry, 17, 241–245.Google Scholar
  52. Zettlemayer, A.C., Young, E.J., and Chessick, J.J. (1955) Studies of the surface chemistry of silicate minerals — III. Heat of immersion of bentonite in water. Journal ofPhysical Chemistry, 59, 962–966.Google Scholar

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© The Clay Minerals Society 2010

Authors and Affiliations

  1. 1.Department of Civil and Environmental EngineeringUniversity of Missouri-ColumbiaColumbiaUSA
  2. 2.Colorado School of MinesEngineering DivisionGoldenUSA

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