SYMPOSIA PAPER Published: 01 January 2004

Performance of Geosynthetic Clay Liners Used in Two Landfill Closures in a Coastal Area of Florida


Landfill caps may present GCLs with one of the most difficult environmental conditions in which to perform. The low confining pressure of the cover soil allows for greater separation of the sodium montmorillonite platelets. The GCL is more susceptible to ion exchange at these low confining pressures. Coastal areas of Florida have a greater potential for the presence of calcium within the sandy soil cover placed over the GCL to function as a drainage layer and protective cover. This combination of low confining pressure and the presence of calcium carbonate may increase the hydraulic conductivity of the GCL over time. This paper will detail an investigation of a 5 year old plus GCL barrier layer within two landfill closures for a coastal Florida county and determine if any changes in properties of the bentonite/GCLs have occurred. The samples were tested for hydraulic conductivity, fluid loss, swell index, and ion content. The samples were also inspected for root penetration. Samples of the soils placed above and below the GCL were also analyzed for ion content and bentonite compatibility.

Author Information

Mackey, RE
S2L, Inc., Maitland, FL
Olsta, JT
CETCO, Arlington Heights, IL
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Developed by Committee: D35
Pages: 53–71
DOI: 10.1520/STP12198S
ISBN-EB: 978-0-8031-5500-8
ISBN-13: 978-0-8031-3484-3