Slag-Cement-Bentonite Slurry Walls
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 131, Issue 6
Abstract
In both the United States and the United Kingdom, slurry walls are used as vertical barriers to control groundwater flow and to contain contaminants as part of waste containment systems. In the United States, slurry walls are commonly constructed using soil-bentonite (SB) and the barrier typically consists of a mixture of select soil, bentonite, and bentonite-water slurry. Alternatively, in the United Kingdom, the barrier wall comprises a mixture of cement, blast furnace slag, and bentonite-water slurry. After a comparison of the two techniques, this paper presents the results of permeability and unconfined compressive strength tests on twenty-one different mixtures of slag-cement-bentonite (slag-CB). The slurry wall materials tested in this study were prepared using sample formulations originating in the United Kingdom and materials originating in the United States. Unconfined compression tests were performed on samples after one month of curing, while permeability tests were performed after one, two, three, six, and twelve months of curing. For the mixtures tested and cured twelve months, two mixtures (one having 20% cementitious material with 70% slag replacement and another having 15% cementitious material with 80% slag replacement) were found to have the lowest hydraulic conductivity . The data show that 0 to 60% slag replacement had little effect on hydraulic conductivity of the resulting slag-CB mixtures. However, the hydraulic conductivity drastically decreases as the slag replacement increases from 70 to 80%. As expected, the unconfined compressive strength increased as the cementitious material content increased from 10 to 15 to 20%. The slag-CB consolidates rapidly and has compression characteristics similar to other high moisture materials.
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Acknowledgments
The writers appreciate the time the following individuals spent discussing the details of US and UK slurry wall practices. These individuals, along with their affiliations at the time of their assistance, include: Ian Martin and Robert Harris, Environment Agency; Paul Tedd and Stephen Garvin, Building Research Establishment; Stephan Jefferis, Golder Associates; Kelvin Potter, ICI; Lucy Philip, Leeds University; Robert Essler, Keller Ground Engineering, Peter Barker, Bachy-Soletanche; Peter Braithewaite, Arup Consultants; and Steven Day, Geo-Solutions, Inc. The writers also appreciate the work of Bucknell University students Todd Sheldon, Erika Reed, and Joseph Marut, in the performance of consolidation tests. The writers would also like to thank the reviewers for their detailed review and numerous suggestions for revision and improvement. The writers gratefully acknowledge the support of EPSRC, provided by their Visiting Fellowship Research Grant for Dr. Evans, and the McKenna Foundation, for their support of Shana Opdyke.
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© 2005 ASCE.
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Received: Mar 16, 2004
Accepted: May 28, 2004
Published online: Jun 1, 2005
Published in print: Jun 2005
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