Abstract
This study presents experimental investigation of indigenous clays mixed with Bentonite to assess their suitability in potential use as clay liners. Soil samples with 0, 4, 8, and 12% Bentonite content from three different sites in Peshawar region were tested for various geotechnical properties. Grain size distribution, specific gravity, Atterberg limits and free swell were found through laboratory tests using appropriate ASTM procedures. Maximum dry density and optimum moisture content were calculated using Atterberg limits in available relationships. Finally, one dimensional consolidation tests were conducted to find relevant parameters for calculating hydraulic conductivity. A decrease in specific gravity, increase in free swell, and in optimum moisture content, decline in maximum dry density and hydraulic conductivity was observed with increase in Bentonite content across all three soil samples. During free swell, the soil clusters become larger leading to formation of floccules resulting in the narrowing of inter-particle space and thus blocking of permeable paths. It is concluded that 8% Bentonite content by weight yields a suitable mixture for a clay liner that has hydraulic conductivity in the range of recommended limits.
Highlights
The safe and efficient disposal of solid waste is indispensable as it poses a hazard to the environment, and is an emergent problem in developing countries
The soil gradation for particles retained on sieve No 200 (>75μm) was calculated using sieve analysis whereas the soil particles passing 75 μm sieve was evaluated by hydrometer analysis following ASTM D7928-17
All three soils were observed to have greater than 10% of soil sample passing sieve #200
Summary
The safe and efficient disposal of solid waste is indispensable as it poses a hazard to the environment, and is an emergent problem in developing countries. Contamination of ground by solid waste can be minimized by simple means with the provision of proper landfills, which incorporate clay liner that acts as a barrier and prevents leachate to reach clean and hygienic sub-surface water. Guidelines have been compiled for selecting suitable soil properties and compaction procedures that are likely to result in low hydraulic conductivity [8] These guidelines are normally based on experience and generally include adequate ranges or minimum values for properties that describe composition of soil (e.g., particle-size distribution, Atterberg limits, swelling indices) and recommendations for selection of compaction criteria (i.e., control of water content and dry unit weight) and compaction machinery.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
