The most common nonwoven is a needle-punched product. Staple fibers or continuous filaments are bonded by mechanically entangling the fibers with barbed needles. It looks and feels like black felt. Occasionally, the product will be manufactured in white or orange. Orange nonwovens serve as a warning barrier indicating contaminated soils.
Another method of manufacturing nonwoven geotextiles is spunbonding. During this process extruded filaments are spun onto a collecting belt and bonded by applying heated rolls. It results in a smoother and stiffer product with reduced pore size and increased strength. Spunbond products are usually gray in color.
- Needlepunched Nonwovens
- Spunbonded Nonwovens
- Civil Nonwovens
- Environmental Nonwovens
Nonwoven filtration examples include wrapping geotextile around a pipe or enclosing stone with a geotextile to create a system that allows water to pass, but keeps soil from infiltrating and clogging the system. These are often referred to as French drains. Nonwoven drainage fabrics are an economical alternative to graded aggregate and sand filters and can eliminate many of the problems associated with using, purchasing and transporting aggregate.
Nonwovens can also be used in separation applications. These include paver patios or walkways; outdoor areas where cows or horses exercise to prevent mud; stream crossings in light traffic areas; under playground mulch; or for park-on/drive-on applications in wet areas. AREMA recommends heavy weight nonwovens as separators under railroad ballast.
Another use for a nonwoven geotextile is as asphalt overlay fabric. Overlay fabric increases pavement life by eliminating water intrusion and increasing pavement flexibility. Environmental grade, or M.A.R.V. weight nonwovens perform the critical task of protecting impermeable liners in public and private landfills.
Nonwoven Applications
- Asphalt Overlay
- Cow Carpet
- Drainage
- French Drains
- Filter Fabric
- Geomebrane Cushion
- Landscape Fabric
- Pipe Wrap
- Railroad Ballast Separation
- Rip-Rap
- Separation Under Pavers
- Subsurface Drainage
- Trench Drains
- Underdrains
- Weed Barrier