Highways and Roads

Highways and Roads

TYPAR Geosynthetics are extensively used in civil engineering in the construction of highways - from preventing intermixing of sub-base and subgrade layers, control erosion on slopes, for roadside drainage, as part of Low Impact Design (LID) projects for infrastructure access and in the construction of retaining walls, bridge abutments and steep slopes.


Subsurface drains are drains built with a permeable conduit such as corrugated plastic, geonet, tubing, tile, stone, pipe or any combination installed beneath the ground surface to collect and/or convey drainage water to an outlet.

Subsurface drains are used for a wide variety of purposes including:

  • Edge-of-pavement drains (Figure 1) 
  • Interceptor drains (Figure 2) 
  • Subsurface structure drains (Figure 3) 
  • Blanket drains (Figure 4)

Effective subsurface drains are essential to prevent the harmful and destructive force of uncontrolled water. Most infrastructure failures in applications such as highways, airfields, railroads, parking lots, buildings, retaining structures, mines and dams are attributed to the harmful effects of uncontrolled water. 

With the use of TYPAR® Geotextiles, subsurface drains are simple to design and inexpensive to construct. TYPAR Geotextiles filter water flowing to the drain and minimize soil particles from passing, reducing the chance of system clogging. As TYPAR geotextiles are available in a wide variety of opening sizes, the appropriate grade can be selected depending on the soil particle size in critical applications. 

A TYPAR geotextile is recommended in all subsurface drains to provide a separator to prevent intermixing of the drainage aggregate materials with the subgrade soil and therefore protect the drainage system from clogging. 

How TYPAR Geotextiles Work

The failure of a drainage system is caused by the intermixing of the free-draining aggregate materials with the subgrade soil, which leads to clogging of the aggregate. TYPAR Geotextiles separate soil from the aggregate stone, which minimizes intermixing, helping to maintain the integrity of the drain, and reserving the original design and design life of the drain. TYPAR Geotextile’s tensile strength, puncture resistance, tear resistance, opening size and hydraulic properties make it an ideal filter fabric for drainage systems. 

The primary design requirement of a drainage system is the development of a natural graduated filter layer (Figure 5). TYPAR Geotextiles promote the development of such layers because the unique bonded fibers create a pathway that resembles a well graded aggregate filter. TYPAR Geotextiles provide an effective drainage structure since it has both high permeability and the ability to retain soil particles adjacent to the textile, which effectively minimizes the piping of the natural soils and reduces fine particles from entering and clogging the drain.

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TYPAR Geotextiles
Grass & Ground Reinforcement
TYPAR C-Class Geotextiles