Structural Contribution of Geosynthetic-Reinforced Working Platforms in Flexible Pavement (05-2281)
Tuncer B. Edil, University of Wisconsin, Madison

A study was conducted to evaluate the structural contribution of geosynthetic-reinforced granular layers that are used as working platforms during construction over soft subgrade, to the pavement structure under in-service loads. Based on the elastic deflections from a Large-Scale Model Experiment (LSME) simulating a prototype-scale pavement structure and from the field Falling Weight Deflectometer (FWD) tests, the relationship between back-calculated elastic modulus and bulk stress was obtained. The effects of reinforcement by four types of geosynthetics in the LSME were compared with those obtained from the field tests. A slightly higher reinforcement effect in the LSME were obtained compared to the field test. The improvement in layer coefficients are rather small for the nonwoven geotextile and drainage geocomposite (10%) and somewhat higher for the geogrid (40%) and for the woven geotextile (18%) in a 0.30-m thick granular working platform layer (treated as a subbase). The contribution of geosynthetics would be even less to the elastic improvement of the pavement system having a thicker subbase layer.