Nonwoven geotextiles

Nonwoven geotextile Nonwoven sheets Nonwoven textiles Nonwoven wipes... 

In nonwoven geotextiles, the fibers are much thinner but far more numerous. The various types are needle-punched, resin-bond, and melt-bond. All contain a labyrinth of randomly oriented fibers that cross one another so that there is no direct line of flow. The fabric must have enough open space to allow liquid to pass through, while simultaneously retaining any upstream movement of particles. The needle-punched nonwoven type is very commonly used as a filter material. 

In gas-collector systems, either a granular soil layer or a needle-punched nonwoven geotextile is placed directly beneath the LML or clay of a composite cap system. Gas compatibility and air transmissivity are the design factors that must be considered. Methane, the most predominant gas, should be compatible with most types of geotextiles including PET, PP, and PE. 

Nonwoven geotextiles. Nonwoven fabrics are defined as a sheet, web, or batt of directionally or randomly oriented fibres/filaments, bonded either by friction, and/or cohesion, and/or adhesion. In general, nonwoven fabric formation can be considered as a two-step process web formation (aligning the fibres with certain orientation characteristics) and bonding these fibres by mechanical, thermal, or chemical means. This two-step process has formed the classification of nonwoven structures, i.e. carded, airlaid, spunlaid, meltblown, needlepunched, hydroentangled, adhesive bonded, thermal bonded, stitch bonded, etc. Some of the important processes that are used for the manufacture of nonwoven geotextiles are discussed below. 

Chemical bonding. A binder such as glue, rubber, casein, latex, cellulose derivative, or a synthetic resin is used for bonding the filaments or short fibres together and these materials are known as chemically or adhesive bonded nonwoven geotextiles. 

Hwang GS, Lu CK, Lin MF, Hwu BL, Hsing WH. Transmittivity behaviour of layered needlepunched nonwoven geotextiles. Textile Research Journal 1999 69 565-9. 

Rawal A, Anandjiwala RD. Comparative study between needlepunched nonwoven geotextile structures made from flax and polyester fibres. Geotextiles and Geomembranes 2007 25 61-5. 

Rawal A, Sayeed MMA. Mechanical properties and damage analysis of jute/polypropylene hybrid nonwoven geotextiles. Geotextiles and Geomembranes 2013 37 54-60. 

Rawal A, Saraswat H. Stabilization of soil using hybrid needlepunched nonwoven geotextiles. Geotextiles and Geomembranes 2011 29 197-200. 

Giroud J-P. Poisson s ratio of unreinforced geomembranes and nonwoven geotextiles subjected to large strains. Geotextiles and Geomembranes 2004 22 297-305. 

Rawal A, Anand SC, Shah T. Optimization of parameters for the production of needlepunched nonwoven geotextiles. 7 Ind Textil 2008 37 341-56. 

Kothari VK, Das A. Compiessional behaviour of nonwoven geotextiles. Geotextiles and Geomembranes 1992 11 235-53. 

Pahneira EM, Remigio AFM, Ramos MLG, Bernardes RS. A study on biological clogging of nonwoven geotextiles under leachate flow. Geotextiles and Geomembranes... 

Protection Protection of geomembrane against puncture by means of a cushion of nonwoven geotextile. 

The use of a nonwoven geotextile to cushion a geomembrane to prevent it from getting punctured. 

Nonwoven geotextiles first form a loose web or layers of fibers or filaments, arranged in either an oriented or random pattern, prior to fixing them by bonding (by an adhesive or thermal fixation) and in this way a cohesive planar stmcture is developed. 

Woven Geotextiles Nonwoven Geotextiles Knitted Geotextiles SUtch-bonded Combination... 

Table 3.5. Transition temperatures (in °C) of thermoplastic materials used for geosynthetics (geomembranes, nonwoven geotextiles, geocomposite drains, geogrids etc.). In addition to polyolefins PE and PP, polyester PET and polyamides PA 6.6 and PA 6 and polyvinyl chloride PVC are also used, the letter, however, only to a small extent...

Fig. 3.23. Details of the specimen holder. The top wedge is kept in position just by the friction force between geomembrane on the bottom wedge and nonwoven geotextile fixed on the bottom surface of the top wedge...

Originally, a sand layer (0/2 mm medium sand) was used as a mineral protective layer against the coarse-grained drainage layer. To aid installation, a thin nonwoven geotextile was often placed on the geomembrane. In... 

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