Textiles in Geotextiles Dr Muhammad Mushtaq Mangat

www.mushtaqmangat.org

Geotextiles   Permeable fabrics which, when used in

association with soil, have the ability to separate, filter, reinforce, protect, or drain.

  These are made from polypropylene or polyester, geotextile fabrics come in three basic forms:

  woven (looks like mail bag sacking),

  needle punched (looks like felt),

  heat bonded (looks like ironed felt).

  [http://en.wikipedia.org/wiki/Geotextile]

http://www.conhur.com/geotextile.html

Start of modern geotextiles [1]

  In the early 1960s and 1970s, some pioneering engineers wondered if textiles

  could be used to control soils under difficult conditions

  Very wet soils need draining and textiles were used to line drains, to prevent mud and silt from clogging up the drains.

  Similarly, engineers tried to use textiles beneath small access roads constructed over very soft wet soils. [1].

  It was found that these textiles helped to increase the life and performance of roads.

  Also, early work was being undertaken in the laying of textiles on the coast to prevent erosion by wave action.

  During the last 20 years of the 20th century, the use of geotextiles spread geographically worldwide and in area terms their use increased almost exponentially.

  It is expected that their use will continue to increase into the 21st century [1].

Geosynthetics

  In the field of civil engineering, membranes used in contact with, or within the soil, are known generically as ‘Geosynthetics’.

  This term encompasses permeable textiles, plastic grids, continuous fibres, staple fibres and impermeable membranes.

  Textiles were the first products in the field, extending gradually to include additional products, but have remained by far the most important of the range.

Geotextile types

  Geotextiles basically fall into five categories:   Woven

  Heat-bonded nonwoven Needlepunched nonwoven

  Knitted and   Fiber/soil mixing [1]

The most common types of geotextiles are woven and non woven.

  Woven for:

  Sediment control

  Unpaved road bases

  Strengthening paved roads

  Erosion protection

  subsurface drainage.

  It possesses the following features:

  Woven Polypropylene

  UV Resistant

  Rot Resistant

  Biological Degradation Resistant

  Chemically Inert

http://www.erosionpollution.com/geotextile-types.html

Non woven geotextile

  Used for

  Roads

  Roofs

  Railroads

  Ponds

  Dams, trenches

  Landfills.

  Possess the following features:

  100% Propylene Staple Fibers

  Needle-Punched

  Random Network Formation

  UV Resistant

  Rot Resistant

  Biological Degradation Resistant

  Stable Within 2-13 pH

http://www.ecvv.com/product/2625680.html

http://www.erosionpollution.com/geotextile-types.html

The main geotextile fiber-forming polymers

  Two most common fiber polymers used for

the manufacture of geotextiles are:

  polypropylene and polyethylene

  Polyester is almost inevitably used when high

  strengths are required

Essential properties of geotextiles

  Three main properties which are required:

  Mechanical responses

  Filtration ability

  Chemical resistance

Mechanical responses   It includes:

  The ability of a textile to perform work in a stressed environment

  Ability to resist damage in an arduous environment

  Ability to cope with the expected imposed stresses and its ability to absorb those stresses over the proposed lifetime of the structure without straining more than a predetermined amount

Mechanical tests [1]   tensile testing by means of a wide strip test

  pore size testing by dry sieving

  water flow testing normal to the plane of the textile

  puncture resistance testing

  creep testing

  perforation susceptibility (cone) testing

  water flow testing in the plane of the textile

  testing of sand/geotextile frictional behaviour

Geotextile and filtration

  The woven geotextile’s separation action prevents the mixing of dissimilar soils allowing each soil layer in the road structure to function as intended.

  The high tensile strength and low elongation properties of woven geotextiles impart stability into the road section reducing rutting and extending roadway life.

  [http://www.nilex.com/products/geotextiles/woven_geotextiles]

Chemical resistance

  There are four main agents of deterioration:

  Organic

  Inorganic

  Light exposure

  Time change within the textile fibers [1].

References

  [1] Rankilor, P.R., Textiles in civil engineering, in Handbook of Technical Textiles A.R. Horrocks, Anand, S. C., Editor 2000, Woodhead Publishing Ltd Cambridge.