Shear strength parameters of compacted fly ash–HDPE geomembrane interfaces

The aim of this paper was to determine the interface shear strength between geomembranes with different textures, used for artificially sealing waste disposal sites, and compacted fly ash or fly ash with various percentages of cement added. Tests were conducted in a classic direct shear apparatus, with the aid of a modified bipartite cylindrical box. The box was equipped with an additional part, which enabled interaction testing between compacted waste and high-density polyethylene geomembranes. It was found that interface strength does not depend significantly on sample compaction and cement content. Only membrane structure has an effect on shear strength between waste sample and geomembrane. The value for peak and residual strength was twice as great for geomembranes with diverse textures compared to smooth geomembrane. For geomembranes with clear surface structure, greater values for interface friction angle were obtained, while for smooth geomembrane, greater values for adhesion were found.