Geosynthetics in Reinforcement and Subgrade Separation in a Structural Section

Geotextiles have been widely accepted as a separation layer in pavement structures. Strength of a pavement requires that the coarser layers not be infiltrated by finer subgrade materials. However in practice, this is not always achievable. For silty type soils, when saturated conditions occur with repeated loads, high pore
pressures develop in the subgrade causing the material to become unstable. Fines are then forced into the voids of the aggregate base over time lowering the shear strength of the base course and decreasing the drainage capacity. With pumping, the result is a reduction in the effective thickness of the road system. This can occur rapidly over very soft soils, and over time creating the need for early maintenance. The geosynthetic is designed to act as a separation interlayer to prevent aggregate from penetrating the subgrade under action of applied loads. It can also prevent the intrusion of the subgrade soils into the base layer.