Abstract
ABSTRACT
Sedimentation volumes of montmorillonite soils in aqueous solutions of methanol, acetone, glycerol, dioxane, ethylenediamine, ethanolamine, and urea were determined. This technique was used for screening the soil shrinkage potential of waste components. The sedimentation volumes are interpreted in relation to the characteristic adsorption to the clay mineral for each organic compound.
Presence of water greatly affects the clay-organic interaction. With methanol and acetone, sedimentation volumes increase as a function organic concentration up to a limit but decrease at higher organic concentrations. In contrast, the dielectric constant decreases monotonically with increasing organic concentration. Dioxane showed a decrease in sedimentation volume for increasing organic concentrations up to 1% (molar basis) with no further effect at higher organic concentrations. The other organics behaved differently, indicating the need to consider separately the response of clay to each organic-water mixture. Expectations based on dielectric constants alone are inadequate.
A soil-liquid parameter, free swell difference (FSD), derived from the sedimentation test results, is discussed as a simplified parameter for representing soil behavior under exposure to organic-water mixtures. FSD for water-methanol and water-acetone correlates with the basal spacing and hydraulic conductivity results reported in the literature.
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