Durability

There are several factors relating to fibre selection that must be considered in relation to end product durability:

Polymer
Polyethylene and polypropylene are recognised for their chemical & UV resistance.

Polyesters offer good mechanical properties but the ester group hydrolyses in the presence of water and this process is accelerated by alkaline conditions. 

This could result in the loss of mechanical properties and a change in filter performance. Consequently, polyester is also susceptible to heightened degradation where in contact with concrete, cement or lime-treated soil.

Fibre morphology
Fibres that are mechanically drawn to increase their tensile strength (high tenacity) will exhibit increased resistance to both chemical attack and oxidation.

Low-cost fibre is available to geotextile manufacturers, usually as a by-product of another manufacturing process such as carpet making where it has been formulated for aesthetics rather than performance. These fibres will be of mixed origin and can therefore have inconsistent properties. Moreover the consistency of performance, and hence the quality of the resultant geotextile, will be inferior to those produced from prime-quality, virgin fibre manufacture to a controlled specification.

Geotextiles can also be produced from both industrial and post-consumer recycled fibres. 

Such materials can comprise fibres with different thicknesses, different surface area to volume ratios and different colours. Some types of degradation such as caused by UV, are more pronounced when surface area is high compared with volume, whilst others such as diffusion and absorption are inversely related to thickness. It is therefore vital that the fibres used to manufacture geotextiles for use as revetment underlayers are manufactured with durability in mind.

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