Mechanical Response of Geosynthetic-Reinforced Flexible Pavements

Abstract

Laboratory-based, large-scale experiments are reported on pavement test sections with aggregate base layers containing a layer of geosynthetic reinforcement. The tests involved comparative reinforced and unreinforced test sections with pavement layer materials and thicknesses commonly encountered in the field. Pavement load was provided by a nontranslating, cyclic load applied to a plate resting on the pavement surface. The test sections contained an extensive array of sensors to measure pavement load, surface deformation, stress in the base and subgrade layers, and strain in the asphalt concrete, base, subgrade, and geosynthetic layers. Test section variables include geosynthetic type, geosynthetic placement position within the base, and base layer thickness. The test results show a significant improvement in the permanent deformation behavior of the pavement system due to geosynthetic reinforcement for the variables examined. Stress and strain measurements illustrate reinforcement mechanisms pertinent to paved roadways, which include a reduction of radial strain developed in the bottom of the base, an improved vertical stress distribution on the top of the subgrade, and a reduction of shear deformation in the top of the subgrade. These mechanisms result in lower vertical strain in the base and subgrade layers. A comparison of benefits due to reinforcement and those realized by the addition of aggregate base shows that geosynthetic reinforcement and additional base aggregate provide similar structural enhancements to the pavement system.