GEO TEXTILE
The
principal characteristics of the geo textiles products can be grouped into
technical development of geotextiles in:
1.
Filtration function
2.
Drainage function
3.
Separation function
4.
Reinforcement function
5. Wrapping / Lining function
The
Filtration Function:
Filtration
is the process which allow the water to drain out of the soil and at the same
time to control the displacement of the particles migrating into the drainage
medium.
Non-woven
geo-textile can be advantageously used for filtration and separation in
drainage operation.
The
Drainage Function:
The
geo-textile can provide some flow capacity in their plane, generally used as a
vertical drainage placed in embankments, also railroads highways and runways of
airport are built over substandard soil. Water drains more quickly due to fine
grained granual material and at the same time prevents fine particles of soil.
Particularly where poor soils have to covered by good quantity fill geo-textile
are widely used to separate layer, it can separate the routes stone from
cohesive substandard soil.
Advantages
of geo textile in Road Construction:
Mixing
of substandard soil and stone and ultimately the road cracks get prevented.
Road
stone can easily be removed and the fabric can be taken off and expose the soil
for the treatment.
Saves
large quantity of roadstone, it prevent punching of stone into soil beneath.
The
geo textile is more applicable in railways construction where the soil
possesses low load bearing capacity.
The
Reinforcement Function:
The geo textile can stabilize reinforce and
support the earthworks.
For retaining soil, at the sides of dam’s geotextiles are used purely for the purpose of reinforcing.
The
Wrapping / Lining Function:
The
geo textile are generally applicable for lining solid waste disposal and pounds
to prevent the pollution. The geotextile (geo jute) bags fill up with sounds
are exclusively used for the protection of earth dam during flood. The lining
functions such as transmit water from the soil into the drain also the lining
preserve the moisture benefit the soil.
Raw
Material for Geo Textile:
Most
of the geo textiles are made up of synthetic polymers and few of them are with
natural biodegradables fibers or steel wires also use.
The
use of biodegradable fiber is limited because they are resistant to chemical
and biological degradation.
For
controlling reflective cracking in pavements, glass fiber has occasionally been
used in application.
jute,
wood shavings and paper stripes are the incorporated biodegradable material
within geotextile.
The
four main polymer most widely used as the raw material for geo textile are:
1.
Polyester
2.
Polyamide
3.
Polypropylene
4. Polyethylene
Polyester
Fiber is good resistance to microorganism, high modulus, good, oxidizing agents and ultraviolet rays.
Polyamide
It has high abrasion resistance and chemical resistance is fairly high. Polyamide fibres do not play an important role in geo-textile since they lose strength on prolonged contact with water.
Polypropylene
It has excellent resilience and recovery is good when
loading is cyclic, which again favours its use in geo textiles.
PP fibers has non sensitivity to chemicals, chemically
most inert, which favour its use in geotextiles.
The PP fiber is one of the lightest of all fibers in textile having
density of 0.9 g/cc.
Polypropylene fibres can perform better when used in geo
textile under road construction subjected to cyclic loading due to traffic.
PP fiber having low resistance to UV light is but this can be overcome adding UV stabilizer
like carbon black before extrusion.
Another drawback of polypropylene is susceptibility of PP fibres to creep under sustained load.
Polyethylene
Lower cost is the major advantage and the availability of
the material is high
It creeps under sustained load.
Polyethylene fiber has high resistance to normal
substances in ground.
There is a requirement of UV stabilizer to improve its resistance to ultraviolet radiation.
Products
of Geotextiles:
1.
Geo mattress
Geo mattress is a double layer fabric which separated by means of spacer yarn which basically ensures the continuity of the two layers of the fabric shell as well as thickness. The mattress get woven on looms using dobby for spacer yarn on double clothes weaving principle. The multi filament high denier nylon polyester yarn with zero twist and synthetic splits are used in making the fabrics.
2.
Composite
In
geo-textile composite comprises of needle punch non-woven with the central
woven meshed cloth and exhibit good hydraulic properties with the high modulus
of the woven scream.
Composite consists of central woven fabric, sandwich between two layers of fibers needle punched into non-woven fabric.
3.
Polymer net, grids:
Nets consists of two sets of rough round polymer strands that cross at a constant angle to produce a open geo-textile with large diamond or rectangle shape aperture. The strength of geotextile needs be maintain between 210 Kn/meter.
4.
Geo textile grids:
Geo textile grids are manufactured from polymer sheet, which involves precise punching of regular pattern of holes into the sheet. Carefully controlled stretching of the sheet in one direction while it is gently heated, this is followed. The grid a high tensile stiffness in this direction due to the activity of stretching the sheet. A Uni-axial grid has the greatest strength properties in one direction and formed narrow rectangular aperture.
5.
Strips, webs, and ties:
Polymer
strip geo textile are a development of a class of industrial plastic product
known as linear composite, the term signifies that they contain two or more
linear polymer and they formed into a long continuous length such as ropes or
stripes.
The
product made from geo-textiles type have high tensile strength.
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