Notched Constant Tensile Load (NCTL) Test for High-Density Polyethylene Geomembranes
A modification of an old test method, the notched constant tensile load (NCTL) test, is reintroduced to evaluate the stress-cracking performance of high-density polyethylene (HDPE) geomembranes. In this modified test, notched dumbbell-shaped specimens are subjected to a range of constant tensile loads in a 10% Igepal (CO-630) solution at 50°C. The method has been proposed to ASTM and is being considered by a task group within Committee D-35 on Geosynthetics. This paper presents the test procedures, results of a reproducibility study, and four sets of interlaboratory tests.