Fibres used for natural geotextile products

2 Illustration of the cross-sectional features of bast fibres. 

Fiber type Cell width ( t) Cell length (mm) Mean aspect ratio Fibre width (It) Fibre length (mm) 

Fibres can be processed to be finer and shorter than the figures given in Table 11.1, so as to meet end-use requirements. The ultimate fineness and length would approximate closely the cell dimensions, suitable as papermaking pulp. Thus, the average ultimate fibre length of flax would be 25 to 35 mm jute, on the other hand, would be 2 to 3 mm. 

The lignin and heinicellulose polymers are responsible for such physical and chemical properties as biodegradability, flammability, sensitivity towards moisture, thermoplasticity, and degradability by UV-light [11], (See Table 11.2). 

Hemicellulose Biodegradability Thermal degradability Moisture absorption 

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The fibres used for natural geotextile products are plant or vegetable fibres, although some research and development studies have considered the use of very low grade sheep s wool and wool waste. Figure 11.1 shows a classification of well known natural fibres. However, the only ones that meet with the technical requirements, cost effectively, are the bast fibres jute, hemp, kenaf and flax (also called soft fibres because they are from the softer region of the plants), and the hard (or leaf) and fruit fibres sisal and coir. Others of the remaining fibres, e.g. wood fibres, are sometimes used as fillers within the textile structure. 

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