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This paper presents a case history of an exhumed geomembrane beneath a landfill in New Jersey, U.S.A. The geomembrane taken from the landfill has been in service for the past 22 years. The liner was exhumed due to a lateral expansion at the site. The owner plans to tie into the existing liner sys-tem along with the new cell’s construction. Hence the opportunity arose to exhume a section of textured 1.5 mm (60 mil) HDPE geomembrane that was in service and experiencing actual field conditions of compression, temperature and leachate exposure since its installation.
Most durability research has been laboratory work making use of accelerated aging tests. Rarely are we presented the opportunity to access actual geomembranes that have undergone field exposed conditions. This site experienced hydraulic heads of 3 m (9 ft.) and leachate temperatures as high as 65°C. Samples were exhumed at the site of both the sheet material and the seams. Fortunately, quality assurance testing of the geomembrane during installation was very rigorous and used ASTM Standards still currently used. Thus with this new data, a direct comparison was made of the as-manufactured test results versus current test results after exposure to MSW long-term field conditions at the site. Original property values are con-trasted to the aged material values and also to the current GRI-GM13 specification values. Test results in-dicate that there was very little change in the material. All physical, mechanical and endurance properties have remained essentially unchanged and well above current specification values.