A thermodynamic approach on the effect of salt concentration on swelling pressure of water-saturated bentonite

Research output: Contribution to journalConference article

Abstract

The effect of salt concentration on swelling pressure (dPext) of water-saturated bentonite was calculated based on the thermodynamic data of water at montmorillonite surface and of water in solutions of various salinities coming in contact with the montmorillonite. Activities (aw) of water at montmorillonite surface were obtained as a function of water content and temperature by a vapor pressure method, and the relative partial molar Gibbs free energies (dGw) of the water were determined. Water affected from the montmorillonite surface was estimated to be almost all interlayer water. dPext versus montmorillonite partial density was estimated for solutions of various salinities and compared to data measured for various montmorillonite contents and silica sand contents. The calculated dP ext decreased with increasing salinity. The effect of salinity on dPext was not clear in the measured data due to the scattering in the measured data. This cause is presumed to be due to the increase of the ionic strength of porewater by dissolution of soluble minerals.

Original languageEnglish
Pages (from-to)307-312
Number of pages6
JournalMaterials Research Society Symposium Proceedings
Volume1124
Publication statusPublished - Nov 17 2009
Externally publishedYes
Event2008 MRS Fall Meeting - Boston, MA, United States
Duration: Dec 2 2008Dec 4 2008

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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