Performance of Reinforced–Stabilized Unpaved Test Sections Built over Native Soft Soil under Full-Scale Moving Wheel Loads

This paper presents the findings from an ongoing research study that evaluated two recently developed geosynthetic products: a triaxial geogrid and a high-strength woven geotextile for reinforcing or stabilizing roads constructed over native soft soil in the state of Louisiana. Six full-scale test lane sections were constructed: two were reinforced by one and two layers of triaxial geogrids, respectively, while high-strength geotextile was used to reinforce two of the other sections with aggregate layers of different thicknesses. The remaining two sections were left as controls: one was constructed over a sand embankment 30 cm thick representing the common practice in southern Louisiana. The unpaved test sections were subjected to a full-scale moving wheel load applied by the accelerated loading facility. A variety of instrumentation was used to measure the load-associated and the environment-associated pavement responses and performance. Results of the full-scale testing on the unpaved test sections demonstrated the benefits of geosynthetic reinforcement–stabilization in reducing the permanent deformation in the pavement structure. The test sections’ resilient behavior did not seem to be influenced by the presence of geosynthetics. In addition, instead of the soft soil subgrade, the aggregate layer was the primary contributor to the total permanent deformation–surface rutting of the unpaved sections under the testing conditions in this study. Geosynthetics were mobilized and generally exhibited a strain around 0.2%.