GEOWEB® Geocells and GEOBLOCK® Grass Pavers Stabilize Vegetated Road Shoulder for Private Racetrack Nestled in the White Mountains

Project Background

In 2013, Club Motorsports began the construction of a unique private racetrack at the southern edge of the New Hampshire White Mountains. They designed the track to be a “country club” for car enthusiasts. The design featured a 2.5-mile road course on over 100 wooded acres and boasted breathtaking views of the mountain range to the north. The beauty in the design was only outweighed by the impossible landscape it would cover. It would take over four years, blasting nearly 200,000 cubic yards of ledge, and moving over a million cubic yards of material to complete the racetrack.

The challenge of this project was incorporating 250 feet of elevation change into 15 unique track turns. Racing curbs flowed into grassed shoulders and large grassed drainage swales. The grass swales, along with the major elevation difference, and an average track width of 50 feet, meant that a simple rain event would cause a tremendous amount of watershed. The stormwater runoff would devastate the site, but the unique elevation change and aesthetics of the grass shoulders all added to the allure of the track. It was clear that creative erosion control was going to be the answer.

3D Geocells and Porous Pavements Promote Vegetation and Provide Load Support for Road Shoulders

When cars skid off the racetrack, the tires can create large ruts, which are a safety hazard to other drivers. To prevent rutting, the road shoulders need to be compacted. Establishing vegetation in compacted soils is very difficult, so multiple soil tests were done to see what would be required to build up the soil health. Quick-acting lime, quick-starting fertilizers, and a slow-release organic fertilizer were added to the road shoulders.

This combination was very successful, but some areas needed special attention. Sections of the shoulder that experienced concentrated stormwater runoff were of particular concern. In those areas, the GEOWEB® 3D Soil Confinement System was installed to structurally confine the topsoil and allow the vegetation to establish. Through an interconnected honeycomb-like network, 3D geocells confine and stabilize soils that would otherwise be unstable under loading. The GEOWEB system creates permeable, stable shoulders that reduce rutting and eliminate degradation of the shoulder and adjacent sealed pavement.