Geotextiles are commonly used as a protection layer of the geomembrane in the construction of landfills for liquid and solid waste containment. Heavy weight nonwoven geotextiles are also used for collection and lateral transmission of liquids and gases in a capping of waste (gas venting).
The aim of the separation function is keeping either two terrain layers of different granulometric composition or two layers consisting of different materials separated, without preventing water circulation.
The filtration is the function that defines the possibility of a geotextile to act as a filter preventing the migration of the fine particles of the base terrain and allowing the water to flow out through the surface of the nonwoven geotextile. It has to be designed considering three apparently contrasting criteria:
- The retention requirement
- The permeability requirement
- The non-retention requirement
The applications in which geotextiles have to fulfil a protection function are usually constructions of tunnels, dumps, underground constructions, foundations, catchment basins, flat roofs. In all these cases the geotextile is used for protecting the geomembrane, that fulfils a waterproofing function in the structure.
Drainage is the geotextile capacity of transporting liquid or gas along its plane.
The geotextile reinforcement function with nonwoven geotextiles is obtained through products with an extremely high resistance to tensile strength and therefore of course unit weight. Fulfilling a reinforcement function usually means that the geotextile has to constrict the terrain thus making it less sensitive to deformation under load.
Geodren PP/S/T has often been used in the last few years, also for the construction of landfills and dams, as a consequence of the frequent use of geomembranes. The reasons of the success of these new materials are represented by their better laying operations, their more technical reliability, and, above all, their lower costs compared to traditional waterproofing systems done using concrete slabs, bitumen, clay layer etc..
For what concerns the construction of tunnels, galleries and under ground structures, Geodren PP/S/T is able to carries out two main functions: the protection of the geomembranes and the drainage of the percolating water. It is very important that the water-proofing of a tunnel is done in a professional way.
The quality control: All Acme Mills geotextiles, independent of the quality of the raw material used, are top quality in their category. This is due above all to the fact that the quality system with which the company operates complies with the requirements of the regulation UNI EN ISO 2001:2008, better known as VISION 2000.
Damage during installation: This is one of the most delicate stages affecting the performance of a geotextile once it has been laid. A specific regulation EN ISO 10722-1 defines the procedures of the test on the damage suffered by the geotextile when it is being laid.
GEODREN PPST results are very good even compared to other geosynthetic materials, since the reduction of their mechanical performances after installation is very limited, which means that the mechanical and hydraulic features of these geotextiles are preserved even at the moment of installation. In fact the elongation of our nonwoven geotextiles allows the product to adapt to the irregularity of the surface without breaking. We show you hereafter a comparison chart between different geosynthetic materials with the results of the damage during installation on different soils and laying conditions for the products listed here below. The testing has
been made by an independent laboratory.
GTN: GEODREN PP/S/T 500P g/m2.
GGW1: Woven geogrid, in high tenacity polyester yarns coated PVC
GGW2: Woven geogrid, in high tenacity polypropylene
GGE: Mono-directional extruded geogrid, in polypropylene
The UV resistance of polypropylene staple: The breaking strength of PP raw materials is reduced by UV exposure. The reduction of the breaking strength depends on exposure time, exposure intensity, temperatures,
chemical and mechanical influences. Therefore exact values of the impact cannot be forecast.
The reduction of the breaking strength is measured in number of years which pass until the breaking strength has reached 50% of its original value. Our experience and Lab test on Xenotest 1200 provide following values for PP raw materials:
Acme Mills wide range: GEODREN products meet the different performance needs according to the application in which they will be used. This line includes polypropylene and polyester geotextiles manufactured with both top-quality fibres and recycled fibres, white or multicoloured.