Types of Geosynthetics

Geotextiles and geomembranes are the two largest groups of geosynthetics, according to the Geosynthetic Research Institute (GRI), with geogrids representing a rapidly growing segment of the industry. Geotextiles are made from synthetic fibers that are manufactured into flexible, porous fabrics either by standard weaving machinery or by a random or nonwoven matting process. Geomembranes are impervious thin sheets of rubber or plastic that can be used for linings and covers of solid, liquid, or gaseous storage structures, but they have also found a home in civil engineering and a number of applications have been developed. Geogrids are manufactured from plastics, which are formed into a grid-like configuration. They are used almost exclusively as a soil reinforcement product, especially with retaining walls and under roadways.Geonets, geosynthetic clay liners, geopipe, and geocomposites are less prevalent in the industry than the big three listed above. Geonets, sometimes called geospacers, are used for drainage projects and generally consist of a parallel set of polymeric ribs, which, when opened, form large apertures and a netlike configuration. Geosynthetic clay liners have a thin layer of bentonite clay sandwiched between two geotextiles. The three layers are physically bonded together or needle punched or stitched. They can be used as a primary or secondary liner, or can be utilized as a composite component beneath a geomembrane. GRI calls geopipe the “orphan of the civil engineering curriculum” and states that what is more commonly know as “buried plastic pipe” is “perhaps the original geosynthetic material still available today.” Geopipe is used for drainage. A geocomposite is a combination of the above products or any geosynthetic that is combined with another material such as plastic sheets, or steel cables or anchors.