Field Performance of GCL under Ion Exchange Conditions
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 123, Issue 10
Abstract
Five Victorian reservoirs of brick pillar and arch construction were renovated using geosynthetic clay liners (also called bentonite/geosynthetic composites) (GCL) as roof sealing materials. The GCL was predominantly sodium bentonite and contained some 2% of calcite. GCLs were laid on leveled, original puddled clay packed between and above the brick arches. There was an overlying gravel layer connected to a drainage system that, in turn, was covered with soil and seeded with grass. Leaks through roofs into stored potable water were discovered. Excavation and exposure of the GCL showed that they were finely cracked in many places. Samples of the GCL bentonite from several locations at each of five sites had a high moisture content. Also, the GCL had a much reduced exchangeable sodium and increased exchangeable calcium content when compared to the dry unused GCL. Laboratory experiments, lasting for a limited period, were carried out to simulate operating conditions of the GCL whereby water falling on the ground and reaching the GCL flowed across the GCL in the overlying gravel layer to collector drains. Similar but less extensive ion exchange, calcium for sodium, was found here also. The evidence demonstrates that calcium from calcite, contained in the GCL bentonite, exchanged with sodium and, in so doing, contributed to shrinkage and cracking. Supplementary sources of calcium for ion exchange probably came from overlying calcareous soil and water from firehoses used to field test the integrity of the GCL.
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References
1.
Egloffstein, T. (1994). “Properties and test methods to assess bentonite used in geosynthetic clay liners.”Geosynthetic clay liners, R. M. Koener and H. Zanziger, eds., 51–72.
2.
Fleming, W. G. K., and Sliwinski, Z. (1974). “Practical considerations affecting the construction of diaphragm walls.”Proc., Conf. ICE, 1–10.
3.
Grim, R. E., and Güven, N. (1978). “Bentonites, geology, mineralogy, properties and uses.”Devel. in Sedimentology, 24.
4.
Madsen, F., and Nüesch, R. (1994). “Characteristics and sealing effects of bentonites.”Geosynthetic clay liners, R. M. Koener and H. Zanziger, eds., 31–49.
5.
“Method of tests for soils for civil engineering purposes. Part 3: Chemical and electrochemical tests.” (1990). British Standard 1377.
6.
Richards, L. (1954). “Diagnosis and improvement of saline and alkaline soils.”USDA handbook 60, U.S. Govt. Printing Office, Washington, D.C.
7.
Rogers, W. F. (1963). Composition and properties of oil well drilling fluids, 3rd ed., Gulf Publishing Co., Book Div., Houston, Tex.
8.
Taylor, D. (1993). “Cure for heavy metal headaches.”Constr. News, Sept., 30.
9.
Van Olphen, H. (1977). An introduction to clay colloid chemistry, 2nd Ed., John Wiley & Sons, Inc., New York, N.Y.
10.
Van Olphen, H., and Fripiat, J. J. (1979). Data handbook for clay minerals and other non-metallic minerals.
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Copyright © 1997 American Society of Civil Engineers.
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Published online: Oct 1, 1997
Published in print: Oct 1997
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