Geo-Textile fabrics are permeable textile materials used with foundation, soil, rock, earth etc which is an integral part of a constructed project, structure or system. Advantage of using Geo-Fabrics is to extend the life of roads, improve stability and reduce cost. Research work being carried out at the TRIC is based on a 3-pronged strategy (demand, supply and research) based on sustainable growth of geo textiles in Pakistan.

Mechanical properties of Geo-Textiles are strength, elongation, puncture resistance, tear strength and creep. The hydraulic properties are permeability, whereas in terms of endurance UV resistance is desirable property. Products suitable for use as reinforcement in roads are identified on the basis of the following consideration:

Raw-materials

Geo-Textiles are generally made from 90% Polypropylene fibre the remaining component can be polyester or polyamide fibre. Polypropylene and Polyester fibers are most suitable, due to their stress-strain characteristics, initial modulus, capacity to resist initial stress and deformation under load applied over a period of time. The ideal raw material for reinforcement of roadbed is Polyester, because it is durable and has superior initial modulus and creep characteristics.

Yarn type

Fine, high-tenacity multi filament yarn with high strength, stability and high capacity of interlocking with soil particles are required for the manufacture of Geo-Textiles.

Fabric type and construction

Both knitted, woven and nonwoven fabrics can be used for Geo-Textiles. The fabric construction parameters should give high strength characteristics with permeability. Fabrics must also have the properties of resistance to damage and abrasion. The weight per square meter of the fabrics should be sufficient to give maximum reinforcement to the roads. The usual range of weights of fabrics for use as Geo-Textiles is from 180 gsm to 400 gsm. The woven construction made up of high tenacity multifilament polyester yarn is the most suitable geotextile for reinforcement.

Geotextiles can extend the life of the road and decrease its immediate and life time cost.

Local manufacturers and users

Some of the local manufacturers of Geo-Textiles are Ibrahim Fibers, Dewan Salman Fibers, Rupali and I.C.I. The local users of Geo-Textiles are Pakistan Navy, Irrigation Department of Baluchistan, Civil Aviation Authority, Sui Southern Gas Company Limited, Pakistan Petroleum Limited, Defense Housing Authority, Karachi Port Authority and Hub Pak Salt Refinery. In conclusion it is stated that for the promotion of the manufacture and use of Geo-Textiles, government support, standardization, technical education and research facilities are prerequisites for further development.

Geo-Textiles can be placed on top of asphalt layer with binder. It can also be placed between soil and asphalt for prevention of soil erosion but mostly it is used for road reinforcement.

Firstly high tenacity polyester yarns can be used for Geo-Textiles and secondly either natural fibers or a hybrid of natural and synthetic fibers or other cheap materials made from reprocessing waste can also be used.

About 50% of the water is lost in seepage in Pakistan which can be saved by using Geo-Membranes in cannels and water courses.