Geotextiles additives

Separation. In this function, the geotextile serves to separate two dissimilar materials (Fig. 3), eg, two different soils, landfill material and the native soil, stone material and subgrade sod, old and new pavement, foundation sods and various types of wads, or one of many other similar situations. In some instances, it is difficult to distinguish between the separation and stabilization functions because in both situations the geotextde is serving as a separator. However, in stabilization some additional phenomena occur. 

Geotextiles have a large variety of uses. These can be used for mulch around newly planted seedlings (Figure 7.9). The mats provide the benefits of natural mulch in addition, controlled-release fertilizers, repellents, insecticides, and herbicides can be added to the mats as needed. Research results on the combination of mulch and pesticides in agronomic crops have been promising. 

Additional to the criteria for particle retention, the permeability requirements of the geotextile filter for various soil types must be considered. The permeability of a geotextile filter in severe soil and hydraulic conditions can be reduced by an order of magnitude over its fife. To ameliorate this, it is important that the geotextile maintain or exceed its index permeability while under load i.e. any re-orientation of the fibres should not decrease or increase the permeability. Criteria against clogging have also been recommended for the permeability as well as for the retention properties of a geotextile filter. 

The potential development of electrokinetic geotextUes offers an opportunity to increase the redevelopment of derelict land as a means of reducing the pressure for construction within the natural environment. This electrically conductive material enhances the filtration and drainage functionalities by electro-osmosis and ion migration. Various types of conductive component can be incorporated in the geotextile structure to achieve this effect, but the possible use of activated carbon fibre or similar additives with pollution sorptive surface properties can aid land recovery of poUuted areas. 

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