Geotextiles: Characteristics, Fibers, Products & Applications

Basics of geotextiles

The principal characteristics of the geotextiles 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:

The main function is to allow the water to drain out of the soil, at the same time to control the displacement of the particles migrating into the drainage medium. The non oven geotextile can be advantageously used for filtration and separation in drainage operation.

The drainage function:

• The geotextile can provide some flow capacity in their plane.
• They are generally used as vertical drainage wick placed in embankments.
• Railroads highways and runways of airport are built over substandard soil. Due to fine grained granual material water drains more quickly and at the same time prevents fine particles of soil.
• Geo textile are widely used to separate layer particularly where poor soils have to covered by good quantity fill, it can separate the routes stone from cohesive substandard soil.
• The main advantage of geotextile in road construction are:

1. It saves large quantity of roadstone up to large extent as it prevent punching of stone into soil beneath.

2. It prevents mixing of substandard soil and stone and ultimately the road cracks.

3. Road stone can easily be removed, the fabric can be taken off and expose the soil for the treatment.

The geo textile are more applicable is Road at railways construction where the soil possesses low load bearing capacity.

The reinforcement function:

• The main function of jio textile is the ability of geotic cells are brick embedded in earthwork to distribute over there whole area the forces where intermittent continuous vertical or diagonal acting upon them.
• The geotextile can stabilize rain force and support the earthworks.
• At the sides of dams geotextiles are used purely for the purpose of reinforcing that is for retaining soil.

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 perform the functions such as transmit water from the soil into the drain also the lining preserve the moisture benefit the soil.

Raw material for geotextile:

• Most of the geotextiles are made up of synthetic polymers few Steel wires or natural biodegradable fibres are also use.
• The use of biodegradable fibre is limited because you texted is to be resistant to chemical and biological degradation.
• Glass fibre has also occasionally been used in application related to controlling reflective cracking in pavements.
• The biodegradable materials incorporated within geotextiles are jute, wood shavings and paper stripes.

The four main polymer most widely used as the raw material for geotextile are:

1. Polyester

2. Polyamide

3. Polypropylene

4. Polyethylene

1. Polyester

It is high modulus, good resistance to microorganism, oxidizing agents and ultraviolet rays.

2. Polyamide

It has high abrasion resistance, chemical resistance is fairly high. Polyamide fibres do not play an important role as you textile since they lose strength on prolonged contact with water.

3. Polypropylene

• It has non sensitivity to chemicals.
• It is chemically most inert, which favours its use in geotextiles. It's melting point is 165 degree Celsius. It is the lightest of all fibres having density of 0.9 g/cc
• It has excellent resilience and recovery is good when loading is cyclic, which again favours its use in geo textiles.
• Polypropylene fibres can perform better when used in geo textile under road construction subjected to cyclic loading due to traffic.
• The resistance of polypropylene fibre to UV light is low but this can overcome by adding UV stabilizer like carbon black before extrusion.
• Another drawback of polypropylene is suspectibility of Polypropylene fibres to creep under sustained load.

4. Polyethylene

• It has high resistance to normal substances in ground.
• It creeps under sustained load.
• UV stabilizer is required to improve its resistance to ultraviolet radiation.
• Lower cost is the major advantage.

Types of products of geotextiles:

1. Geo mattress

• This is double layer fabric which can be separated by means of spacer Yarn.
• The spacer yarns ensures the continuity of the two layers of the fabric shell as well as thickness.
• Multi filament high denier nylon polyester yarn with zero twist and synthetic splits are used in making the fabrics.
• It is woven on looms using dobby for spacer yarn on a double clothes weaving principle.
• The fabric shell is then filled with fine grained sand cement ground mix.

2. Composite

• Composite comprise of needle punch non-one with the central woven meshed  cloth and exhibit good hydraulic properties (of needle punch non woven) + the high modulus of the woven scream.
• The overall effect of the scrim is that although it breaks at some places, it continuous to add stability and high modulus to the fabric. Thus it consist of central woven fabric, sandwich between two layers of fibres neddle punched into non-woven fabric.

3. Polymer net, grids:

• Geo textile nets consists of two sets of rough round polymer strands that cross at a constant angle to give a very open geo textile with large diamond or rectangle shape aperture.
• This mesh like appearance lead to termish being initially applied to typical size of a steins and the aperture is 2 mm to 7 mm respectively.
• The strength of geotextile needs be between 210 Kn/metre.

4. Geo textile grids:

• Geo textile grids are manufactured from polymer sheet.
• The first stage of production involves precise punching of regular pattern of holes into the sheet.
• This is followed by carefully controlled stretching of the sheet in one direction while it is gently heated.
• The activity of stretching the sheet allies the polymer long chain molecules in the direction of stage giving the grid a high tensile stiffness in this direction.
• A Uni-axial grid with narrow rectangular aperture is formed and has the greatest strength properties in one direction.

5. Matt's

• Geo textile matts have a comparatively large opening size, similar to that found in some of the finer geotextile nets.
• The distinguished feature between geo textile matts, nets and grids is that the matt's has a distinct 3 dimensional structure where as the form of needs and grids is nearer to that of two dimensional planner structure.
• Most geo textile match are made from semi rigid monofilament lays than 1 mm in diameter.
• This type of geo textile matt is made from nylon 6 containing carbon black and typically 10 to 20 mm thick.

6. Strips, webs, and ties:

• Polymer strip geo textile are a development of a class of industrial plastic product known as linear composite.
• This term signifies that they contain two or more linear polymer and that their formed into a long continuous length such as ropes or stripes.
• The industrial composite was known as paraweb and used for soil reinforcement application.
• This consists of cores aligned high tenacity polyester filament in a black polyethylene sheet containing carbon black.
• Geo textiles type have high tensile strength and their specially produced in stripe formed.
• The main application of this type of geo textile as a protective covering to prevent surface erosion, soil reinforcement application.
• Geo textile tie is a round like version of the geo textiles type in which there is single Central core of high strength filament.

Also Read:

Basics of Geotextiles