Organizations choosing from among geomembrane products evaluate options based on vital factors including containment ability, stability, and chemical resistance. So it’s only natural that they should wonder how long they can expect their chosen geomembrane to last. The answer is a complicated one.
Geosynthetics magazine has reported “how all PE, whether HD or LLD, are not identical—they can have different long-term performances dependent on the PE resin used and the formulation of the stabilizer package. However, such differences are not evident in the conventional mechanical properties, such as tensile strength, break elongation, puncture and tear resistance, and so on.”
It asked, “Do service lifetimes now exceeding 30 years mean that we might expect to see another round of stress cracking failures, as exposed liners finally oxidize sufficiently on the surface to initiate stress cracking?” The magazine went on to urge the establishment of a baseline for each installation and evaluation programs to monitor changes.
“Rather than be taken by surprise when a liner fails or simply expires, it should be possible to monitor the condition of the liner to obtain a few years of notice for impending expiration. One can then plan for a timely replacement without the potential for accidental environmental damage and undesirable publicity.”
Other evaluations of geomembrane durability have focused not on the material used but what were termed external influences such as stresses introduced during installation, the effects of elevated temperatures and degradation due to chemicals present in leachate. One noted that, “In practice a confined HDPE geomembrane will only fail in the long term either by stress cracking at points of constant stress – stone protrusions, stresses across seams, creased wrinkles, textured surfaces.” It concluded that, “the best solution is to select a geomembrane with the highest stress cracking resistance and the best performance in the GRI.GM13 thermal aging test, and to install it carefully.”
The first attempt to evaluate the service lives of various geomembranes was made by the Geosynthetic Institute back in 2005. “Geomembrane Lifetime Prediction: Unexposed and Exposed Conditons,” updated in 2011, begins by noting, “Without any hesitation the most frequently asked question we have had over the past thirty years is ‘how long will a particular geomembrane last.’ ” Factors said to impact service life include ultraviolet light, ozone, temperature, oxidation, hydrolysis, chemicals present and even the presence of radioactive materials.
Agru America’s HDPE and LLDPE geomembranes deliver superior containment performance, slope stability and chemical resistance. Manufactured using the flat die extrusion calendered process, they include:
- Smooth Liner, a tough, flexible liner for containment applications to landfill caps
- MicroSpike Liner, the only textured liner with a consistent core thickness and the highest surface friction values in the industry.
- Super Gripnet Liner, designed for applications where draining and stability are critical, features underside spikes for adherence to steep slopes and easy installation.
- Black & White Liner, which features a white reflective surface that reduces wrinkles caused by thermal expansion.
Agru America is the only U.S. manufacturer using the flat die extrusion calendered process to produce structured geomembranes for the U.S. and International civil/environmental market. With their uniform structure and appearance throughout, Agru geomembranes consistently receive rave reviews from the field for quality, ease of installation and durability.