Hydraulic conductivity of two geosynthetic clay liners with different bentonite granule sizes

Geological Engineering, University of Wisconsin, Madison, WI, 53706, USA

^* Corresponding author: ytan84@wisc.edu

Abstract

Experiments were conducted to evaluate the hydraulic conductivity of two commercially available geosynthetic clay liners (GCLs) with similar properties but different bentonite granule sizes (D₅₀=1.0 mm or 0.3 mm). A synthetic municipal solid waste (MSW) leachate prepared in the laboratory and four actual coal combustion product (CCP) leachates collected from the field were used as permeant solutions to represent different permeant chemical conditions for waste containment applications. The two GCLs had comparable hydraulic conductivity to dilute or moderate ionic strength (I) leachates (< 0.1 M). With more concentrated leachates (I > 0.1 M), hydraulic conductivity of the GCL containing finer bentonite granules (FG) was 10 to 500 times lower than the hydraulic conductivity of the GCL containing coarser bentonite granules (CG) under the same equilibrium conditions. These results suggest that GCLs containing finer bentonite granules may be less vulnerable to permeant chemistry.