Advances in the Use of Geosynthetics for Stabilization of Unbound Aggregate Layers

Abstract

The governing mechanism associated with the stabilization of unbound aggregate layers in pavements is lateral restraint. Reproducing this mechanism in the laboratory maybe challenging because, while the original loading source is cyclic (traffic), lateral restraint develops through interlocking and interfacial friction between the geosynthetic and the aggregate to restrain the development of permanent lateral strains. Considering the relevance of lateral restraint in the quantification of the benefits of geosynthetics embedded within (or adjacent to) unbound aggregate layers, this study focuses on two experimental approaches to quantify this mechanism. The first experimental approach aims at defining a design parameter, identified as the Stiffness of the Soil-geosynthetic Composite (KSGC), which is obtained from Soil-Geosynthetic interaction (SGI) tests and is practical for use in specifications and design. The second experimental approach that quantifies the lateral restraint mechanism involves one-third scale accelerated pavement tests (APTs), which were performed on pavement test sections stabilized with various geosynthetics, diverse in terms of geometry and materials. The rutting from these sections was compared to that in the non-stabilized (control) section to evaluate the Traffic Benefit Ratio (TBR) at failure rut depth for each geosynthetic. The TBR obtained showed a strong linear correlation to the KSGC of the corresponding geosynthetic determined by SGI tests. Overall, the KSGC parameter was found to represent a suitable indicator of the performance of pavements with unbound aggregate layers stabilized using geosynthetics.