When the DIBt (Deutsches Institut für Bautechnik [German institute for construction engineering]) granted its approval for the use of Geosynthetic Clay Liners (GCLs) in class 1 landfills (1997/1998), it also ordered the manufacturers of these approved GCLs to submit proof of the continuous, internal, longterm shear strength over the five-year approval period. It is known that this requirement was fulfilled by NAUE GmbH & Co. KG. However, in 1998 DIBt discontinued its activities related to GCLs in landfill applications. In order to be prepared for the time when the approval expires, we conducted an evaluation of Bentofix® for its continuous long-term shear strength in a joint effort with BAM (Bundesanstalt für Materialforschung und -prüfung [federal agency for materials research and testing]). This joint research project (which was open to participation of other GCL manufacturers) developed a test procedure for GCLs that is based on existing experiment models from BAM approval procedures for structured geomembranes.
Experiments were conducted with a 50 kPa superimposed load at an incline of 2.5 (H) : 1 (V) in 80 ºC hot water. The GCLs must withstand a test period of 365 days without shearing to ensure a minimum functional lifetime of 200 years. On 15 December 2003, NAUE GmbH & Co. KG received an appraisal from BAM about the long-term shear strength of the Bentofix® B 4000 GCLs. This appraisal certifies that Bentofix® B 4000 GCLs, based on the widely promulgated Arrhenius extrapolation, has met the minimum functional lifetime rating of 200 years at 15 °C ambient temperature.
Further experiments on other Bentofix® types will be conducted so that our customers can be assured of the highest quality and safety in documented form.
If you would like to receive further information about the strong, durable, full-surface Bentofix® shear strength transfer, send an email to kvmaubeuge@naue.com with the keyword "200 years" or just give us a call:
telephone +49 (0) 5743 / 41-228, fax 41-284
