Stress crack resistance of HDPE geomembranes has always been a major consideration for geomembrane raw material suppliers, geomembrane manufacturers and end users. In the past, Environmen-tal Stress Crack Resistance (ESCR), often described a “bent strip test”, characterized by ASTM D1693 and other test protocols was common. As resin quality and geomembrane performance levels improved over time and with technical advances this test became less useful as longer and longer test durations (2000 hours or more) were needed to test to the failure of the materials. In response to this issue the geosynthetic industry developed a new testing protocol, Notched Constant Tensile Load (NCTL). NCTL, characterized by ASTM D5397 and other testing protocols which were created tested resins of that era within test dura-tions of a few hundred hours. NCTL is now globally accepted as both a measure of HDPE geomembrane quality and predictive of lifespan. However, in the recent decade, resin and geomembrane performance has continued to again improve and NCTL testing durations of 1000 h or more currently present the recurring issue of a test duration that is too long for technical, quality, and business considerations. New testing protocols examining the stress strain behavior of geomembrane have been found in recent evaluations to offer values that are predictive of stress crack performance. While these new testing protocols have been utilized with some success in the pipe industry, these methods are applied here to geomembranes of a fully commercial scale with results that represent an advancement in the technology of evaluating geomem-branes.
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