STABILIZING UNPAVED AGGREGATE ROADS with 3D Geocell Technology

The Federal Highway Administration 2012 statistics indicate that approximately one-third of all highway miles are unpaved surfaces. A significant opportunity for reducing maintenance costs and improving safety exists through use of three-dimensional geosynthetic geocells to stabilize these unpaved roadway surfaces.

Many of the 1.4 million miles of unpaved roads experience rutting, washboarding (corrugation), settlement over poor subgrades and horizontal translation at curves and corners that can be minimized or eliminated through the use of GEOWEB® geocells. At the heart of these aggregate pavement failure modes is particle translation.

• Rutting occurs as aggregate particles move downward or laterally due to soft subgrade or repeated load cycles.
• Washboarding occurs to dry aggregate pavements where wheel load ‘bouncing’ causes ripples.
• Potholes develop from small depressions where surface water collects–and accelerate with the dynamic forces and pounding of vehicle tires in and out of the ever-increasing depression.
• Erosion rills and gullies form by the horizontal translation of aggregate particles caused by runoff.

All of these pavement failure modes can be controlled with GEOWEB geo

cells as the 3D walls create redundant containers and velocity breaks for the aggregate, hindering particle movement at the surface.

The GEOWEB geocells’ 3D structure confines and stabilizes cohesionless soils, delivering strength and higher performance to soils than when unconfined.  The technology is based on the interaction between hoop stresses in the geocell cell walls and passive earth resistance of geocell systems.

Geocell systems increase the effective structural number for load support, reducing pavement requirements by up to half the depth of traditional designs. This allows for less expensive pavement cross-sections in addition to the beneficial surface stabilization. Significant cost savings are gained as maintenance cycles are reduced and in some cases eliminated.

The cost for GEOWEB geocell integration into a new unpaved roadway is far outweighed by the annual cost savings gained in maintenance reductions and the utility enjoyed by the public, making geocell technology a viable consideration for highway managers.