| Geotextiles | Polypropylene, polyester, and occasionally polyethylene | Separation, filtration, drainage, reinforcement, and erosion control | Roads, railways, drainage systems, retaining structures, embankments, and shoreline protection | Flexible, permeable, available as woven or nonwoven sheets, with adjustable strength and apparent opening size | Performance depends on polymer type, fabric structure, puncture resistance, clogging potential, and exposure conditions |
| Geogrids | Polypropylene, polyester, or high-density polyethylene | Soil reinforcement and load distribution | Reinforced soil walls, steep slopes, road bases, working platforms, and foundation improvement | Open grid structure, high tensile strength, and mechanical interlock with granular soil | Design should consider junction strength, strain compatibility, installation damage, creep, and connection details |
| Geomembranes | High-density polyethylene, linear low-density polyethylene, polyvinyl chloride, and flexible polyolefin | Liquid and vapor containment | Landfill liners and caps, wastewater ponds, irrigation reservoirs, mining containment, and secondary containment | Very low hydraulic conductivity, chemical resistance, and continuous sheet-form barrier performance | Weld quality, seam testing, puncture protection, weathering, subgrade preparation, and thermal expansion require careful control |
| Geonets | High-density polyethylene | In-plane drainage and transmission of liquids or gases | Landfill leachate collection, landfill gas drainage, and drainage layers behind walls | Three-dimensional ribbed structure with relatively high transmissivity under load | Flow capacity can decrease under compression; they are often combined with geotextiles or geomembranes |
| Geocomposites | Combinations of geotextiles, geonets, geogrids, geomembranes, or drainage cores | Combined drainage, filtration, separation, reinforcement, or barrier functions | Wall drainage, landfill systems, road drainage, green roofs, and foundation waterproofing | Multifunctional, space-efficient, and capable of replacing several conventional layers | The interface between components, long-term compressive behavior, and compatibility must be evaluated as a complete system |
| Geosynthetic Clay Liners | Bentonite clay enclosed between geotextile layers | Hydraulic sealing and reduction of liquid migration | Landfill liners and caps, ponds, canals, secondary containment, and soil remediation sites | Low hydraulic conductivity when properly hydrated and relatively easy to install compared with thick compacted clay layers | Bentonite can be affected by chemical compatibility, desiccation, hydration conditions, and high-concentration saline liquids |
| Geocells | High-density polyethylene or other durable polymer strips | Three-dimensional confinement and stabilization of soil or aggregate | Unpaved roads, slope protection, channel lining, load support, and erosion control | Honeycomb-like cellular structure that limits lateral movement and improves load distribution | Cell depth, aperture size, anchorage, infill type, slope angle, and surface drainage affect performance |
| Erosion Control Geosynthetics | Polypropylene, polyester, natural fibers, or polymer nets | Reduce soil loss and support vegetation establishment | Slopes, channels, riverbanks, construction sites, and revegetation areas | Surface protection, sediment retention, flexibility, and—in some products—biodegradability | Selection should match rainfall intensity, flow velocity, slope geometry, vegetation goals, and expected service life |
| Geopipes | High-density polyethylene, polypropylene, polyvinyl chloride, or other polymers | Conveyance and collection of liquids or gases | Subsurface drainage, leachate collection, landfill gas systems, and irrigation or wastewater infrastructure | Lightweight, corrosion-resistant, and available in solid-wall or perforated configurations | Hydraulic capacity, pipe stiffness, bedding, joint performance, deformation, and access for maintenance should be considered |