01122410

Component

Hydraulic conductivity and its vulnerability to changes with time or exposure to chemicals are the major factors in the selection of clayey material for barrier systems in waste containment facilities. In the study presented, water saturated lateritic soil specimens treated with up to 10% bentonite and compacted with standard Proctor effort at 2% wet of optimum moisture content were permeated with deionised water and municipal solid waste (MSW) landfill leachate in sequence. The falling head testing method was used, while the duration of the experiments was 90 days. On permeation with water, specimens with bentonite content ¡Ý 5% by dry weight of soil, achieved hydraulic conductivity, k, lower than typical regulatory limits of k ¡Ü 1.0 x 10-9 m/s, which were maintained at the end of test duration. The natural soil and specimen containing 2.5% bentonite whose baseline k failed to meet the statutory hydraulic conductivity requirement remained above this threshold value after permeation with MSW landfill leachate. Generally, all the soil ¨C bentonite mixtures tested performed well against attack by the leachate. The hydraulic conductivity of specimens increased only slightly by a factor ranging from 1.1 to 1.6, which practically signifies no change in hydraulic conductivity. From this result, it is projected that long-term exposure of barriers built with lateritic soil - bentonite mixtures to MSW landfill leachate will not have adverse effect on the chemical stability of the barrier system.

01120148

09-0620

English

18p

2009

Transportation Research Board 88th Annual Meeting

DVD

Figures (5) ; References (55) ; Tables (5)

Bentonite; Clay; Hydraulic properties; Landfills; Leachate; Moisture content; Permeability coefficient; Soil mechanics; Solid wastes; Solutions (Chemistry)

Geotechnology; Highways; I42: Soil Mechanics

Transportation Research Board Annual Meeting 2009 Paper #09-0620

TRIS, TRB

Jan 30 2009 4:52PM