"Long-term Performance of GCLs: Permeated with Aqueous Inorganic Solutions" Shackelford, Charles Colorado State University
Long-Term Performance of GCLs Permeated with Aqueous Inorganic Solutions Geosynthetic clay liners (GCLs) are factory-manufactured hydraulic barriers consisting of a thin layer of bentonite (~ 5.0 kg/m2) sandwiched between two geotextiles or bonded to a geomembrane. Since 1992, GCLs have been used widely in hydraulic containment applications because of their relatively low cost and very low hydraulic conductivity to water (k 10E-8 cm/s). However, most applications using GCLs involve the containment of chemical solutions that may be incompatible with the bentonite portion of the GCLs, and the results of most hydraulic conductivity tests on GCLs are performed over relatively short test durations (e.g., 6 mos.). As a result, the primary objective of this study, a joint effort between Colorado State University (CSU) and the University of Wisconsin at Madison (UWM), is to evaluate the long-term performance of geosynthetic clay liners (GCLs) permeated with aqueous inorganic solutions over test durations ranging from 6 mos. to 3 yrs. Physical, hydraulic, and mechanical properties of the GCLs both before and after exposure to permeation with distilled water and salt solutions will be determined. The research will include tests to evaluate the long-term hydraulic conductivity, swell, shear strength, and diffusion properties of GCLs. In addition, an exchange program between CSU and UWM will be established based for both educational and research dissemination purposes. The results of this study will advance our understanding of the long-term behavior of GCLs, and should impact the design of waste containment systems involving GCLs.
