Oklahoma Roads

Location: State of Oklahoma

Project Type: Roadway

Application: Unpaved Roads

Product Used: GEOTEX Nonwoven and GEOTEX Woven

From 1987 – 1989 the US Federal Highway Administration (FHWA) and the Oklahoma Center for Local Government Technology tested the effectiveness of separation/stabilization geotextiles in preventing the contamination of unbound aggregate roads from subgrade soils. Nineteen unpaved rural road sites representing a variety of subgrade conditions, aggregate surfacing types, climates and construction methodologies were selected.

At each site test sections with woven and nonwoven GEOTEX® were installed along with control sections. After a single wet season, several control sections lost 4 inches of new surface stone due to intermixing with subgrade soil. This resulted in loss of structural strength and severe rutting. The sections that used the GEOTEX remained in good condition.

Overall the study found that the separation benefit pays for the cost of the geotextile in one year’s time. Additionally, geotextiles increase the effective strength of the subgrade, improve long term stability and increase the load carrying capacity of the unbound materials. The complete findings for this study, FHWA-RT-89-050, are available from the National Technical Information Service (NTIS).