http://worldcat.org/entity/work/id/41579646

Frost Resistance of Cover and Liner Materials for Landfills and Hazardous Waste Sites

The common method of preventing the contamination of groundwater by landfills and hazardous waste is to encapsulate the waste material in a compacted clay liner and cover system. The frost resistance of compacted clay in landfills has been the subject of controversy for many years. Laboratory studies have frequently shown that freezing and thawing significantly increase the hydraulic conductivity of compacted clay soils. However, there has not been any corroborating field evidence. This study more closely examines this problem, and identifies cover and liner materials that would be frost resistant to increase construction productivity and save costs under a CPAR (Construction Productivity Advancement Research) cooperative agreement between CRREL and five private companies. The effects of freezing and thawing on the hydraulic conductivity of two compacted natural clay soils, one compacted sand-bentonite mixture, and three geosynthetic clay liners (GCLs) were examined. Both field and laboratory tests were performed on these materials. The field test site consisted of five test pads (four of clay and one of sand-bentonite), and nine test pans containing three different GCLs. Results showed that freeze-thaw caused large increases (greater than 1000x) in hydraulic conductivity in compacted natural clay, but little measurable change in hydraulic conductivity of the GCLs or the sand-bentonite mixture. GCLs and sand-bentonite mixtures are suitable frost resistant substitutes for compacted clay soils. Considerable cost savings can result if compacted clay soils are replaced with GCLs or sand-bentonite mixtures.

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