or thaw in multilayered systems. USA Cold
This study has also shown that the hydraulic
conductivity of sandbentonite mixtures can be
Regions Research and Engineering Laboratory,
resistant to freezethaw if the sand is uniformly
Special Report 122.
mixed with an adequate amount of bentonite. The
Benson, C., E. Chamberlain, and A. Erickson (1994)
hydraulic conductivity in the sandbentonite test
Methods for assessing freezethaw damage in
pad appeared to remain unchanged after two win-
compacted clay liners. In Proceedings, 17th Interna-
ters of freezing. The sandbentonite test pad also
tional Madison Waste Conference, 2122 September
showed no visible cracks. However, the perfor-
1994, University of Wisconsin. Department of Engi-
mance of the sandbentonite is very sensitive to
neering Professional Development.
incomplete mixing of its ingredients. Further
Bowders, J., and S. McClelland (1993) The effect of
study of the effect of freezethaw, with sufficient
freeze/thaw on the hydraulic conductivity of
control to ensure uniform mixing of the sand and
three compacted soils. In Hydraulic Conductivity
bentonite, should be undertaken. In addition, con-
and Waste Contaminant Transport in Soils (S. Traut-
ditions that limit the problem of piping of bento-
wein and D. Daniel, Ed.). ASTM S7P 1142.
nite should also be explored.
Chamberlain E., I. Iskandar, and S. Hunsicker
The test results show that the hydraulic conduc-
(1990) Effect of freezethaw cycles on the permea-
tivity of the GCL materials is also frost resistant,
bility and macro structure of soils. In Proceedings,
with hydraulic conductivities remaining below 1
International Symposium on Frozen Soil Impacts on
108 cm/s after freezing and thawing. However,
Agricultural, Range, and Forest Lands, Spokane,
there is some uncertainty about the performance
Washington. USA Cold Regions Research and Engi-
of seams, the sealing of construction damage
neering Laboratory, Special Report 90-1.
(cuts), and the effects of the water quality on the
Chen-Northern, Inc. (1988) Results of laboratory
hydration of the bentonite in the GCL materials.
tests on Claymax. Denver.
Additional large-scale field tests are needed to fur-
Estornell, P., and D. Daniel (1992) Hydraulic con-
ther examine these problems and to develop spe-
ductivity of three geosynthetic clay liners. Journal
cific construction guidelines and methods for the
of Geotechnical Engineering, ASCE, 118(10): 1592
use of GCLs.
1606.
The cost benefits of using GCL hydraulic barri-
Geoservices (1989) Freezethaw effects on Clay-
ers in place of compacted clay barriers are signifi-
max liner systems. Report by Geoservices, Inc. to
cant. These benefits result from the elimination of
James Clem Corp.
the soil required for frost protection above the
Kim, W., and D. Daniel (1992) Effects of freezing
hydraulic barrier and from the decrease of the
on hydraulic conductivity of compacted clay. Jour-
thickness of the hydraulic barrier. The value
nal of Geotechnical Engineering, ASCE, 118(7): 1083
added to a waste disposal site by substituting a
1097.
GCL for a compacted clay layer can exceed
Kraus, J., and C. Benson (1994) Laboratory freeze
0,000/acre (4,000/ha) or nearly 16% of the
thaw testing of bentonite barrier materials.
fixed costs of the disposal site.
Co-published manuscript, Department of CEE,
Finally, this study has shown that the sampling
University of WisconsinMadison.
and test methods are important for forensic analy-
Nelson, R.L. (1993) Report of Bentomat freeze/
sis of frost damage to the hydraulic conductivity
thaw test results. Report to CETCO, by Robert L.
of compacted clay liners. The conventional thin-
Nelson and Associates, Inc., Schaumburg, Illinois.
walled tube sampler is not acceptable for frost-
Othman, M., and C. Benson (1993) Effects of
damaged soils, as it compresses the soil and masks
freezethaw on the hydraulic conductivity of three
the damage. Furthermore, the hydraulic conduc-
compacted clays from Wisconsin. Proceedings of
tivity test cannot be done at high stress levels. The
71st Annual Meeting, National Research Council,
stress level must be commensurate with the in-situ
Washington, D.C. Transportation Research Record,
stress. For a cover system, the maximum effective
no. 1369, p. 118125.
stress in the hydraulic conductivity test should not
Paruvakat, N., G.W. Svick, and L.J. Buechel (1990)
exceed 2 lb/in.2 (13.8 kPa).
Freezethaw effects on landfill clay liners. In Pro-
ceedings, 13th Annual Madison Waste Conference,
University of WisconsinMadison, p. 452469.
LITERATURE CITED
Repa, E.W. (1990) Data summary report. Number
Aitken, G.W., and R.L. Berg (1968) Digital solution
1 Landfill costs. National Solid Wastes Manage-
of modified equation to calculate depths of freeze
ment Association, 3 August.
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