Ground separation and support are the two main functions of DuPont™ Typar® in temporary road construction. Since the soil / Geotextile / aggregate system tends to be deformed by imposed traffic loads, special attention must be paid to laps and anchorage:
The prime role of DuPont™ Typar® in permanent road construction is that of ground separation. However, during the construction phase the base courses are often used as a temporary road surface and in these cases Typar® also acts as a support membrane. The installation of DuPont™ Typar® in permanent road construction is identical to that for temporary roads.
Embankments on compressible soil
A geotextile will stretch considerably during consolidation and settlement and, by providing lateral support, will tend to increase embankment stability horizontal.
The side and end laps needed depend on soil properties (CBR), the project nature and on the deformations which might be expected to occur.
Overlaps normally used
Additional area required allowing for overlaps
The two following graphs show the amount of extra DuPont™ Typar® needed, depending on the calculated surface area and the overlap width.
Estimates of the savings possible by sewing or welding instead of overlapping are clearly demonstrated.
For applications where DuPont™ Typar® is used for reinforcement purposes,overlapping requires special attention. Calculations by experienced design engineers may be needed to check the correct transmission of stresses.
Handling of rolls
Thick Geotextiles soak up water. When it rains they are difficult to install because of their increased weight. At sub-zero temperatures they become impossible to use since they freeze solid. DuPont™ Typar® can be stored outside. It does not absorb water and therefore will not freeze.
DuPont™ Typar® rolls take up less space than many other geotextiles, thus storage and transportation are efficient.
DuPont™ Typar® is thin and light, making the compact rolls easy to transport and install. Rolls can be easily cut to the desired width with a chain saw. This is almost impossible with most other geotextiles