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Swelling pressure of a divalent-rich bentonite: Diffuse double-layer theory revisited

  • Physicochemical forces are responsible for the swelling pressure development in saturated bentonites. In this paper, the swelling pressures of several compacted bentonite specimens for a range of dry density of 1.10–1.73 Mg/m3 were measured experimentally. The clay used was a divalent-rich Ca-Mg-bentonite with 12% exchangeable Na+ ions. The theoretical swelling pressure–dry density relationshipPhysicochemical forces are responsible for the swelling pressure development in saturated bentonites. In this paper, the swelling pressures of several compacted bentonite specimens for a range of dry density of 1.10–1.73 Mg/m3 were measured experimentally. The clay used was a divalent-rich Ca-Mg-bentonite with 12% exchangeable Na+ ions. The theoretical swelling pressure–dry density relationship for the bentonite was determined from the Gouy-Chapman diffuse double-layer theory. A comparison of experimental and theoretical results showed that the experimental swelling pressures are either smaller or greater than their theoretical counterparts within different dry density ranges. It is shown that for dry density of the clay less than about 1.55 Mg/m3, a possible dissociation of ions from the surface of the clay platelets contributed to the diffuse double-layer repulsion. At higher dry densities, the adsorptive forces due to surface and ion hydration dominated the swelling pressures of the clay. A comparison of the modified diffuse double-layer theory equations proposed in the literature to determine the swelling pressures of compacted bentonites and the experimental results for the clay in this study showed that the agreement between the calculated and experimental swelling pressure results is very good for dry densities less than 1.55 Mg/m3, whereas at higher dry densities the use of the equations was found to be limited.show moreshow less

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Metadaten
Document Type:Article
Author: Tom Schanz, Snehasis Tripathy
DOI (Cite-Link):https://doi.org/10.1029/2007WR006495Cite-Link
URN (Cite-Link):https://nbn-resolving.org/urn:nbn:de:gbv:wim2-20170425-31592Cite-Link
Parent Title (English):Water Resources Research
Language:English
Date of Publication (online):2017/04/25
Year of first Publication:2009
Release Date:2017/04/25
Publishing Institution:Bauhaus-Universität Weimar
Institutes and partner institutions:Fakultät Bauingenieurwesen / Professur Bodenmechanik
Tag:Geochemical modeling; Soils; High-pressure behavior; bentonite; clays; expansive clays
GND Keyword:Bentonit; Boden; Ton
Dewey Decimal Classification:500 Naturwissenschaften und Mathematik / 530 Physik
500 Naturwissenschaften und Mathematik / 540 Chemie
BKL-Classification:35 Chemie / 35.24 Klassische analytische Chemie
Licence (German):License Logo Zweitveröffentlichung