Which of the following materials is not commonly used for geomembranes?

Geomembranes are synthetic membranes that are used widely in landfill operations to control fluid movement and ensure environmental protection by acting as a barrier. The materials most commonly used for geomembranes include High Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), and Polypropylene (PP). These materials are chosen for their impermeability, durability, and chemical resistance, making them suitable for the containment of liquids and solids, particularly hazardous waste.

Concrete, on the other hand, is not utilized as a geomembrane due to its physical properties. While concrete can be used in various construction applications, it does not function effectively as a barrier in fluid containment scenarios. Unlike the other materials mentioned, concrete is porous and can allow fluid migration, which defeats the purpose of a geomembrane designed to prevent leaks and contamination.

Thus, the identification of concrete as the material not commonly used for geomembranes is accurate, as it does not meet the critical requirements necessary for this specific application.