The earliest of civilization used natural material to improve soil behaviour and to hold the soil. Material like woven matts of Reeds, tree branches alongwith leaves, coconut leaves in coastal areas are age old customs which work as a reinforcement to the soil. Geosynthetics are manmade products manufactured from synthetic polymeric materials and also natural materials. Functions of Geosynthetic Separators Filters Drains Reinforcement Hydraulic Barriers Protectors Erosion Control Systems Classifications of Geosynthetic Geotextile Geotextiles are liner, permeable, polymeric or natural fibre textile materials used in civil engineering for filtration and reinforcement. Geotextiles can be further classified as Woven and Non-Woven Geotextiles. Generally Woven Geotextiles exhibit High Tensile Strength, High Modulus and low Elongation. Non-woven Geotextiles have high permeability and conformability because of their high Elongation characteristics. Geotextiles are available from 0.25 to 7.5 mm thick and have a mass / unit area of 150 to 2000 gms /M2 Functions : Filtration, Cushion, Drainage and Surface Erosion Control. Geomembrane Geomembranes are impervious Geosynthetic that resembles thick, flexible plastic sheets and are usually smooth surfaced. They are relatively impermeable polymeric sheets. They are manufactured with Linear Low Density Polyethylene (LLDPE), Low Density Polyethylene (LDPE) and High Density Polyethylene (HDPE). They are 0.10 to 3.0 mm thick and mass per unit area in the range of 100 to 3000 gms. Functions : Separation, Protection and Containment. Geogrid Geogrids are mesh like or grid with square or rectangular apertures that resembles plastic meshes often seen as garden fences. They are usually made from Polyethylene / Poly propylene / Polyester. The percent open area of Geogrids lies between 40 - 95% with the width of the opening being typically 10 to 100 mm. The rib thickness ranges from 5 to 15 mm and the mass per unit area lies between 200 to 1500 gms. Functions : Reinforcement, Hydraulic Barrier and Surface Erosion Control. Geonets Geonets are similar to Geogrids but have thinner membrane and angular apertures, not square or rectangular but resembling parallelograms. The width of the opening ranges from 5 to 15 mm, the rib thickness from 3 to 10 mm and the mass per unit area is similar to that of Geogrids. Functions : Filtration, Drainage and Surface Erosion Control & Hydraulic Barrier. Geocomposits Geocomposits are multi-layered Geo synthetics bonded to each other comprising of combination of Geotextiles, Geomembranes, Geogrids and Geo nets by themselves or alongwith other materials. They are integrally connected units of Geotextiles and Geonets, Geomembrane and Geogrids and many other combinations. Functions : Separation, Filtration, Drainage, Reinforcement, Protection and Hydraulic Barrier. Geosynthetic Clay Liner (GCL) Typical Geosynthetic Clay Liner is a manufactured sheet having a central core of Bentonite Clay between two Geotextiles and needle punched or otherwise bonded together. Functions : Reinforcement, Hydraulic Barrier, Soil Erosion Control and Protection. Applications Landfills - Solid & Municipal Waste, Hazardous Waste, Industrial and Demolition Waste. Power - Retention ponds, Cooling water ponds, Brine Ponds, Storage, Water Reservoir and Ash Depositories. Concrete Protection - Concrete Pipes and sewer lines, Trenches and sumps, Wastewater facilities, Tunnels, Foundations and floor. Liquid Containment - Water and wastewater, Petrochemical, Agriculture, Aquaculture, Canal Lining and Dams. Industrial - Tank lining, Storm Water, Vertical Barriers, Secondary Containment. Mining - Heap Leach Pads, Solution ponds and Treatment Lagoons. Others - Golf Course Ponds, Decorative Ponds and water proofing.
