Update on GSI's Geotextile Highway Separation Study

摘要

This short paper presents updated information on GSI's highway geotextile separationrnstudy. In the transportation industry one of the major uses of geotextiles is arnseparator between fine grained subgrade soils and the overlying drainable base coursernmaterials in a pavement system. The purpose being to prevent the intrusion of thernfine grained soils into the drainable base materials and vice versa, the gravel baserncourse from protruding into the soil subgrade.rnThis current study, under the auspices of the Geosynthetic Institute, is to evaluate thernperformance of geotextiles as separators under various roadway and environmentalrnconditions. There are currently 13 sites, widely distributed in the U.S., underrninvestigation.rnGeotextiles as separators in pavement cross sections are significantly under-utilized.rnOne of the impediments is the unknown cost-to-benefit ratio of geotextile systems asrncompared to conventional, nongeotextile, ones. While geotextiles have been used asrnseparators between soil subgrade and stone aggregate for over 25 years, their lifecyclernimprovement of pavement systems has only been qualitatively assessed. Thus,rna nationwide study is underway to quantify geotextile performance in this application.rnThe focus is to access the benefits of a geotextile separator used in paved roadsrnunderlain by stiff and firm subgrades. This study is not focused on stabilization orrnreinforcement of highways on soft subgrades, an area in which the benefits ofrngeotextiles have long ago been demonstrated.rnIt is felt that a large database is needed to assess the performance with and withoutrngeotextile separators at the same location, and then a quantitative assessment of thernperformance of the respective sections over the lifetime of the roadway is necessary.rnEven further, this assessment should be national in scope. In this way, all types ofrntraffic, subgrade, climatic and environmental conditions can be included in thernassessment.