Effects of silica fume on the geotechnical properties of fine-grained soils exposed to freeze and thaw

Both the landfill liner and cover systems are the most important parts on a waste disposal landfill site. These systems are generally constructed using compacted fine-grained soils. It is known that the strength and permeability are particularly affected by freezing and thawing cycles in the cold regions. The aim of this study is to reduce the effects of freezing and thawing cycles on the strength and permeability. To modify the fine-grained soils, silica fume generated during silicon metal production as very fine dust of silica from a blast furnace and historically considered a waste product has been used as a stabilizer. The natural fine-grained soils and soil-silica fume mixtures have been compacted at the optimum moisture content and subjected to the laboratory tests. The test results show that the stabilized fine-grained soil samples containing silica fume exhibit high resistance to the freezing and thawing effects as compared to natural fine-grained soil samples. The silica fume decreases the effects of freezing and thawing cycles on the unconfined compressive strength and permeability. We have concluded that silica fume can be successfully used to reduce the effects of freezing and thawing cycles on the strength and permeability in landfill liner and cover systems constructed from compacted fine-grained soils. (C) 2009 Elsevier B.V. All rights reserved.