Geotextiles are sheet rolls of polypropylene fabric made woven or non-woven for use in stabilizing subgrades typically ranging in thickness from 55-170 Mils.
Non-woven geotextiles are geared more toward site drainage and material separation (between subgrade and aggregate).
Woven geotextiles are considered to provide both separation and reinforcement/stabilization of pavements.
Geotextiles are known to increase subgrade conditions. They:
-increase tensile strength of the soil
-reinforce soil and spreading point loads
-minimize ‘rutting’ of pavement should soft spots exist
-filter, drain, and prevent intermixing of aggregate with the weaker soils below
The fabric works in tension to lower the localized bearing stress by spreading the load over a larger area of the subgrade.
Geotextiles may be used in lieu of Geogrid as they are typically less expensive and simpler to install, and many newer geotextile fabrics have equal or greater tension characteristics to geogrids.
The typical crew for placing geotextiles is two laborers. It is also ideal to have a backhoe available for unloading the rolls and moving them about the work area efficiently.
The geotextile material is rolled out onto the subgrade and both the sides and the ends of the material should be overlapped. The overlap typically ranges from 1.5-3’ depending on the manufacturers recommendation and the soil conditions. Trucks should be discouraged from driving on the fabric until the aggregate base is placed on top of the fabric.