BETEX NW Non-woven Fabrics

Non-woven fabrics belong to a group of construction materials that perform important functions in earthworks, road construction and civil engineering. The various special functions, such as separating different types of soil and filtering soils that need to be drained, make it necessary to differentiate between the non-woven fabrics in order to select the right one.

It is often possible to simply choose the correct fabric according to the geotextile robustness classes (GRK) as defined in the “Merkblatt über die Anwendung von Geokunststoffen im Erdbau des Straßenbaues M Geok E” (Leaflet on the use of geosynthetics in earthworks for highway construction). In other cases, the fabric must be chosen according to the site conditions.

The M Geok E is used to determine the suitability of the nonwoven.

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Your advantages

Good mechanical and hydraulic filtration properties

Weatherproof

Good adaptability

Easy to install

General

BETEX NW Non-woven Fabrics are manufactured from high-quality polypropylene spin fibres in one of the most modern production plants in Europe.

This polymer has high chemical resistance, even to aggressive media such as those with a high pH value. In contrast to conventional, purely mechanically bonded products, BETEX NW Non-woven Fabrics are also thermally treated, in a second production stage.

Thanks to this second-phase treatment, the advantages of mechanically bonded non-woven fabrics, such as flexibility and effective filtering, are combined with the robustness and tensile strength of thermally bonded products.

BETEX NW Non-woven Fabrics have a small characteristic mesh size and high water-permeability and thus meet the requirements of even the most demanding types of application.

Non-woven fabrics are assigned to geotextile robustness classes 3 to 5. Their use is specified in the “Merkblatt über die Anwendung von Geokunststoffen im Erdbau des Straßenbaues M Geok E” (Leaflet on the use of geosynthetics in earthworks for highway construction), which ensures correct selection and handling by everyone involved in the construction process.

Güteüberwachung_Geokunststoffe_Geogitter

Functions

Separation

trennen BETEX NW Non-woven Fabrics separate different types of soil. During installation and when the completed structure is in use, they prevent the different materials from becoming mixed as a result of external mechanical or hydraulic loading. This separation allows each different soil layer to maintain its specific properties.

Filtration

filtern The filtration effect of a non-woven fabric becomes more important when, in addition to separation, it also has to contend with the effects of water. In such cases, the structure relies on both the separation and filtration functions of the fabric.

When constructing traffic routes or drainage systems in soils that present a filtration problem (such as silty sands), a suitable filter must be used that can keep the soil in place and drain away pore water without any significant raising of the seepage line.

The right combination of mechanical and hydraulic filtration has been achieved if the soil is held securely in place and water can easily drain away.

Thanks to their thermofixed surface, the mechanically bonded BETEX NW Non-woven Fabric has an adequately dimensioned characteristic opening size and good water permeability.

Technical details

Special guidelines are available for the different applications of non-woven filtration fabrics and these should be consulted when selecting products. Guidelines for the use of non-woven fabrics in road construction are contained in the “Merkblatt über die Anwendung von Geokunststoffen im Erdbau des Straßenbaues M Geok E” (Leaflet on the use of geosynthetics in earthworks for highway construction). Reference to these guidelines is also made in the recommendations of “Geotechnik der Deponien und Altlasten” (Geotechnical Aspects of Landfill and Brownfield Sites) published by the DGGT (German Society for Geotechnical Engineering).

In order to ensure that non-woven fabrics continue to perform their intended function within the structure after installation, geosynthetics are assigned to geotextile robustness classes (GRK) in accordance with M Geok E (Leaflet on the use of geosynthetics in earthworks for highway construction). The geotextile robustness classes take into account the installation method and the type of fill material used.

Important parameters for the allocation to GRK classes include the soil class and grain shape of the soil to be filtered, the load applied by the fill material, and also the stresses encountered during the installation and construction works. The type and method of installation and compaction of the fill material are just as relevant as the expected loading by construction traffic.

The various non-woven fabrics in the BETEX NW range, with their different mass per unit area values and corresponding static puncture resistance values, cover all GRK classes.

Non-woven fabrics are assigned to geotextile robustness classes 3 to 5. Their use is specified in the “Merkblatt über die Anwendung von Geokunststoffen im Erdbau des Straßenbaues M Geok E” (Leaflet on the use of geosynthetics in earthworks for highway construction), which ensures correct selection and handling by everyone involved in the construction process.

Applications

BETEX NW Non-woven Fabrics are used in situations where seepage water from soils with fine or mixed-size grains needs to be drained from poorly draining soils into a drainage system. The fabric separating the soil layers has the task of preventing fine grains from entering and clogging the drainage system and causing it to fail.

Separation layer under a dam

Bound upper construction layers
Unbound upper construction layers
Base layer
BETEX NW Non-woven Fabric

Separation layer in the case of partial soil replacement

Bound upper construction layers
Unbound upper construction layers
Soil replacement
BETEX NW Non-woven Fabric

Separation layer for infilling and covering ditches and channels

Bound upper construction layers
Unbound upper construction layers
Partial soil replacement
BETEX NW Non-woven Fabric
Ditch/channel

Separation layer under bound and unbound traffic routes

Unbound upper construction layers
BETEX NW Non-woven Fabric

Separation and filtration in traffic infrastructure

Block paving
Bedding for paving
BETEX NW Non-woven Fabric
Base course

French drain

Backfill material
BETEX NW Non-woven Fabric
Free-draining fill material
Partially perforated pipe

Trench backfill

In-situ soil
BETEX NW Non-woven Fabric
Free-draining fill material
Partially perforated pipe

Drainage layer for slopes (perforated pipe)

Topsoil
BETEX NW Non-woven Fabric
Seepage water
Free-draining fill material
Partially perforated pipe
Sealing membrane, if required

Separation and filtration layer for drainage systems

Soil and vegetation
BETEX NW Non-woven Fabric
Sealing membrane
Free-draining fill material
Partially perforated pipe

Reinstatement of a slipped embankment by installing a perforated pipe

Soil and vegetation
Standard inclination 1 : 1.5
Plane of previous slip
BETEX NW Non-woven Fabric
Partially perforated pipe
Free-draining fill material
Drainage or longitudinal road drainage

Filter layer behind gabions

Backfill material
BETEX NW Non-woven Fabric
Gabions
Drainage pipe

Data

Properties	NW 9	NW 10	NW 13	NW 16	NW 21	NW 26
Product type	Mechanical bonded and thermally treated nonwoven
Raw material	Polypropylen (PP) white
GRK	without	without	3	3	4	5
Areas of application
Roof greening	●	●	●	●	●	●
Drainage system			○	○	●	●
Railway construction (with approval)			●	●	●	●
Green areas	●	●	●	●	●	●
Road and traffic area			●	●	●	●
Underground car park greening	●	●	●	●	●	●
Road construction			●	●	●	●

● suitable | ○ partly suitable (project-related assessment necessary)

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Installation

The subsoil should be as flat and even as possible in order to ensure full contact with the fabric across its entire surface.
The fabric must be laid flat and free of creases. Creases resulting from the shape of the structure should be removed by cutting the fabric and allowing it to overlap.
Then follows the installation of the fill material, on the basis of which the corresponding non-woven fabric was selected according to the GRK class. The covering of the non-woven fabric with soil can be easily slotted into the construction schedule within a two-week period.
When filling and compacting material on top of the fabric, care must be taken to prevent displacement or creasing of the fabric.

Our detailed installation and laying instructions for BETEX NW Non-woven Fabrics must also be followed.