This paper presents field results from a three year study focused on the performance of geosynthetic materials in transportation related drainage applications. The application areas of interest were mainly highway edge drains, although selected retaining wall drains and erosion control systems were also involved. Included in the study are geotextile filters, geocomposite edge drains, geocomposite sheet drains and, to a limited extent, plastic pipe. In many instances, the geotextile was observed to be the key element in the overall success or failure of the system. Thus the geotextile, serving in a primary function as a filter was the major focal point of the investigation.
The paper presents the results of exhuming ninety-one (91) field sites in seventeen (17) states throughout the United States. The results give a clear assessment of geosynthetic drainage systems from a long-term field perspective. Furthermore, it allows for specific recommendations to be made to avoid those situations where problems occurred. In a subsequent paper in these Proceedings the results will ultimately be used to challenge the necessary design formulas currently available for geotextile filters in highway drainage applications.