Assessing the shear-strength properties of geomembranes textured using the spray-on technique

One of the techniques commonly used to create a surface texture on a polyethylene geomembrane consists in spraying filaments on a smooth geomembrane. When adequately produced, this solution provides a geomembrane exhibiting good friction properties, while preserving the mechanical and durability properties of the base, smooth geomembrane. In the first part of the paper, key aspects related to the manufacturing of spray-on texture are presented, along with key characteristics of the finished product. Despite having been supplied for over 30 years, the quality control and specification of spray-on texture has remained a ‘black-box’ for end-users. In the second part of the paper, the strategy which has been used over three decades by the BAM (Germany) to assess the reliability of this technology, in a context of product certification. To facilitate acceptance of the spray-on technique on markets relying on conformance testing instead of certification, Blond et al. (2022) [1] introduced the inclined-plane compression test, which was successful at measuring an index property reflecting the friction properties of the geomembrane and could be measured on the finished product. Blond et al. (2023) [2] also showed that the test offers an opportunity to estimate the peak interface shear strength of geomembrane/geotextile interfaces. In the third part of the paper, an intensive testing program is conducted to assess the repeatability of the test. It is shown that this technique can be successfully used to control, and to specify geomembrane interfaces.