Functions of Geosynthetics in Road Construction

Geosynthetics in road construction are quite common, including geotextile, geogrid, geocell, geonet and geomembrane. These geosynthetics can fulfil one or more of the functions a road structure needs. For example, in 1970 geosynthetics were used to improve the performance of roads on soft soil. From 1980 onwards, geosynthetics were developed to reduce the risk of cracking in asphalt.

Functions and applications of geosynthetics in road construction

The figure above shows several possible placements of geosynthetics in a road structure, along with their functions. In general, the functions can be described as follows:

Separation

The geosynthetic is placed between two different material layers to preserve the integrity and function of each layer. The key consideration here is the survivability of the geosynthetic during construction.

Filtration

Geosynthetics act as a filter, allowing water to flow through the geosynthetic while soil particles are retained by it. The key considerations are the permittivity and pore size of the geosynthetic.

Reinforcement

Geosynthetics have tensile strength that acts as reinforcement, maintaining the stability of the soil-geosynthetic composite. The key design parameter is the tensile strength of the geosynthetic.

Stiffening

Geosynthetics can control the deformation of the soil-geosynthetic composite. The key to this function is the increase in stiffness resulting from soil-geosynthetic interaction.

Drainage

Geosynthetics allow gas or liquid to flow so that it drains properly. The key to this function is the hydraulic conductivity and thickness of the material.