Separating added subbase layers from the native sub-grade layer has been proven to be an effective method for thousands of years. Use of woven or non-woven geotextiles improves the engineering behavior of roads and runways while fulfilling the following functions:

• Preventing pumping of fines from the subgrade to the base course.
• Maintaining planned base thickness and preventing loss of added material to soft soil.
• Distributing vertical forces over a large area.

Using geotextiles in the road cross section prevents differential settlement, making it possible to reduce subgrade thickness where necessary.