FORNIT^® 20 biaxial geogrid test section
Construction haul road
Concord, North Carolina

In February 1999, HUESKER, Inc. was contacted by a Concord, North Carolina excavating contractor who was experiencing severe rutting on a haul road, due to the low bearing capacities of native silts and soft clay soils. The haul road consisted only of the existing subgrade soil, and had not been constructed with a base course layer aggregate.

HUESKER, Inc. recommended to the contractor that a test section be installed using FORNIT^® 20 biaxial geogrid on the haul road as a solution to the rutting problem.

The installation procedures and test methodology used for the FORNIT^® 20 biaxial geogrid test section are outlined below:

1. A 60-foot section of the rutted haul road was leveled by back- dragging a bull dozer blade across the rutted areas.
2. A full width (17.0 feet) by 40-foot section of FORNIT^® 20 biaxial geogrid was placed directly above the leveled haul road section.
3. Six inches of 1¾ inch minus road base aggregate was placed above the FORNIT^® 20 biaxial geogrid.
4. Six inches of 1¾ inch minus road base aggregate was also placed on the remaining 20 feet of the leveled haul road section (unreinforced).
5. A fully loaded tandem 15-ton dump truck containing approximately 6 cubic yards of native soil was then driven across the unreinforced and reinforced sections of the haul road.
6. After several truck passes over the test section, visible pumping and rutting of the unreinforced section was observed, while the reinforced section showed no visible pumping.