ABSTRACT
Geomembranes can be produced with or without surface texture. This choice is generally driven by design requirements, in particular the slope stability, but also the safety of users and wildlife. Overall, a bit less than half of textured geomembranes worldwide are produced by coextrusion, a bit more than a third are embossed, and a bit less than a fifth are sprayed with polyethylene filaments. For coextruded textures, Blond & Elie (2006) have shown that there is a correlation between the height of the asperity, measured by ASTM D7466, and the shear-strength properties of the interface between the geomembrane and an adjacent material. Adesokan & Blond (2018) have shown that the density of asperity may also further influence the interface shear-strength properties. However, there is little information available on the performance of the two other texturing techniques frequently used for geomembranes, i.e., embossing the surface, or spraying it with polyethylene particles. Finally, there is a consensus on the limited performance of ASTM D7466 to adequately predict the performance of geomembranes with an embossed or a spray-on texture. In this document, the various techniques used to create a surface texture on a polyethylene geomembrane are described. The results of an experimental program aiming at measuring their shear-strength properties against a geotextile is presented. A new technique to qualify the performance of textured geomembranes is proposed, which can be used to generate an intrinsic property of the geomembrane, and which can also be used in manufacturing quality control to certify the geomembrane / geotextile interface friction angle.
