Geotextiles or geosynthetics (general denomination) are plane, continuous materials, woven or nonwoven, manufactured from synthetic fibres and/or artificial and/or natural fibres, through needlepunching (nonwoven), weaving or melt spinning. They are used in construction works, for drains, separation layers, filters, embankment and slope reinforcement as well as other constructions.
Restrictions in using (very important)
it is strictly forbidden for geotextiles manufactured from waste to contain more than 10% of biodegradable fibre (cotton, bast fibres, wool)
it is forbidden to deliver geotextiles manufactured from synthetic and artificial fibres in the oil and gas industry, given the risk of explosion due to static charge. Only geotextiles manufactured from natural fibres can be delivered for this domain.
Advantages of using geosynthetics:
using geotextiles simplifies the execution of construction works and increases productivity;
it spares important quantities of stone materials, wood, bitumen, fuels, as geotextiles lead to reducing the thickness or replace stone material layers of up to 20-60 cm;
it decreases the total mass of handled and transported materials (up to 1000 times).
Calculation example: In order to build a drainage layer – gravel separator on a surface of 1000 m2, a layer with a thickness of 30 cm is needed (standard execution variant).The total volume is of 1000 x 0.3 = 300 m3 of material.
The total weight is of 300 m3 x 1400 kg/m3 = 420 000 kg gravel = 420 tons. If a geotextile with a mass of 400 gr/m2 was used, the total weight would be of 400 kg, so the weight handled would be reduced by approximatively 1000 times. This means that about 21 lorries of 20 tons would be necessary for transporting the gravel, so the advantages are obvious.
the ratio resistance/mass has values considerably higher in comparison with other construction materials;
at pressure, the geotextiles reach relatively high elongations, avoiding breaking at uneven stress and allowing to adapt to irregularities in the ground.
Recommendations for putting into work
Irrespective of the role in the work and of the nature of the work, the following recommendations shall be respected:
it is forbidden to store the geotextiles outdoors, exposed to sunlight or to other atmospheric factors.
irrespective of the nature of the work, laying the geotextile while it is wet shall be avoided (except if the tender book drafted by the designer stipulates otherwise);
when the geotextile is unrolled, the appearance of creases on its surface shall be avoided. Remove all eventual creases or if this is not possible, cut them and overlap the edges in the unroll direction;
overlapping the roll edges shall be of 20-30 cm, in the machine direction on the geotextile;
the puncture on the surface of the geotextile is forbidden if the geotextile shall have a protection role.
