Composition and Production of Geomembranes

This article on the composition and production of geomembranes is intended to familiarize readers with this relatively new material. Geomembranes are flexible, waterproof materials used in civil engineering structures, such as :

• tanks ;

• DAMS;

• canals ;

• waste storage facilities ;

• tailings storage and many other types of structures.

This article describes geomembranes, indicating what they are made of and how they are made. The information provided in this article should enable the engineer who decides to use a geomembrane to understand and anticipate the practical implications of his decision.

This article begins by presenting the main component of a geomembrane: the waterproofing compound. The base material of the waterproofing compound, which is polymer or bitumen, gives the geomembrane its waterproofing properties. But this base material is never alone. In addition to the base material, the waterproofing compound includes additives with different functions, such as :

• reduce costs ;

• facilitate production ;

• improve sustainability, etc.

As some geomembranes are reinforced, the article describes the various textile products used to reinforce geomembranes. The reasons why certain geomembranes are reinforced are analyzed, with a discussion of the advantages and disadvantages of such reinforcement.

The main geomembrane production methods are described below:

• extrusion ;

• calendering ;

• impregnation ;

• coating ;

• co-extrusion ;

• co-laminating, etc.

As the surface finish of geomembranes is important, particularly to ensure their stability on slopes, the production of geomembranes with a rough surface is covered.

Geomembrane assembly methods are described in detail. These methods depend on the geomembrane. Thermoplastic bituminous and polymeric geomembranes are heat-sensitive and can therefore be thermally welded. Elastomeric polymeric geomembranes are not temperature-sensitive. They cannot be welded. They have to be joined using special adhesive tapes.

Quality control of geomembranes is essential. It must be carried out at the geomembrane production plant, in the prefabrication workshop and in the field....