Durability Assessment of HDPE Geomembrane in a Concrete Water Supply Canal: A 10-Year Case Study

In 2008, a 1.5 mm smooth high-density polyethylene (HDPE) geomembrane was applied as a lining over 800 m of a concrete water supply canal in southeaster Brazil. This study aims to enhance the understanding of geomembrane durability through a case study of a HDPE geomembrane after 10 years, comparing samples submerged in water with those exposed to weather. Mechanical parameters such as tensile strength, tear resistance, and puncture resistance were tested and compared to GRI GM13 standard. Submerged samples primarily faced mechanical damage risk from debris, while weather exposed samples suffered mainly from mechanical, thermal and UV degradation. Results indicated that all parameters for submerged samples exceeded GRI GM13 requirements. Conversely, weather exposed samples showed some variations from the values established by the GRI GM13 Standard. Of the 11 parameters tested, 7 met the GRI GM13 standards, including tensile strength and tear resistance in both machine (MD) and transverse (TD) directions, and puncture resistance. Only transverse elongation at break showed a 40% reduction in the minimum value of GRI GM13. Most of the parameters for the weather-exposed samples were within 80% of the results for the submerged samples, with the exceptions of the tensile strength and elongation at break-both in transverse direction-, which were within 50%.