Geotextile manufacturing processes

3 Geotextile manufacturing processes and their effects on properties and functions 

The impact of the manufacturing process on the geotextile s mechanical properties is easily demonstrated with a standard stress—strain curve. Fig. 3.1 shows that the different types of geotextiles have a greatly differing behaviour under strain. 

By understanding that the properties of a geotextile have an influence the functions they provide, one can imagine that certain types of geotextiles have a predisposition to fill specific functions. Table 3.4 shows the main families of geotextiles compared with their performance in satisfying their principal functions. 

The specihc stmcture of each type of nonwoven geotextile, which is a result of the manufacturing process, has a direct impact on the capacity of the geotextile to perform its function in the soil. Table 3.5 shows in greater detail the main relationships of the manufacturing process, the structure of the geotextile and its performance in the functions for which it is adapted. 

Geotextiles are made from polymers that are available in the form of pellets, cut fibres, yams, filaments or strips. These raw materials must be received at the production site and inspected to ensure their conformity with the specifications of their purchase order. For each raw material, the specific and well-defined parameters must be verified and 

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Figure 3.7 Woven geotextile manufacturing process flowchart.

Figure 4.2 Natural geotextile manufacturing process sequences.

Nonwoven geotextiles are formed by the bonding of random arrays of synthetic fibres (see chapter Geotextile manufacturing processes). Fig. 20.1(b) shows the typical random stmcture of nonwoven geotextiles which commonly are composed of polypropylene fibres but can also be composed of polyester fibres. 

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