One of the earliest field studies on geotextile performance in roads began in 1972 on a farm access road inSmyrna, Delaware. An initial report on the site was prepared in 1974 and key samples were taken after20, 35 and 40 years of service. The material characteristics of these samples have been tested extensivelyto determine the long-term survivability and impact of geotextile materials on road base and surfaceintegrity. The 40-year data and site observations, presented here and offering an update on data presentedto TRB in 1994, show that a significant and beneficial roadway performance can be maintained acrossdecades when geotextiles are used for soil separation and filtration/drainage improvement in the subgrade.The continued integrity of the subgrade, supported by the geotextile, has minimized erosion of theunpaved surface of the farm access road.The data are important not only for farm access roads but for roads in general. Unpaved roads are a strongpredictor of paved road performance. In lacking the extra surface layer (e.g., asphalt), an unpaved road’sresistance to surface erosion and subgrade instability provides a path to better paved road service livesand lower maintenance costs.Also, the data are significant in that the original study was not intended to assess long-term durability;yet, that has become the focus with the site still accessible and functioning.
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