Evaluating the Performance of Geogrid-Stabilized Aggregate Layers for Low-Maintenance Roadways through Accelerated Traffic Loading

ABSTRACT: The depletion of high-quality aggregates and soft subgrade soils are challenges for transportation agencies when building low-maintenance roads. Unsurfaced roads rely on stiff aggregate layers over soft subgrade to resist a bearing capacity failure from excessive traffic loads. However, the stiffness of the aggregate layers can be extended through mechanical stabilisation with geosynthetics. A full-scale study, using a newly designed apparatus, has been conducted to quantify the performance of geogrid-stabilised aggregate over a soft subgrade under accelerated traffic loading. Field studies can be replaced by this apparatus, and it provides a controlled laboratory setting. The apparatus also has a keen focus on the characterization of the subgrade material over the course of testing. Monitoring and controlling suction throughout the subgrade effectively provide consistent conditions in each test section. Comparison testing focusing on the change in material stiffness and deformations provide insight into the benefits of geosynthetic stabilisation. Agencies often seek to minimize risk by increasing the lifespan of their construction, and geosynthetics can provide an effective method of prolonging the stiffness of the aggregate layer and reducing the degree of rutting over repeated loading.