Evaluation of lateral restraint in geosynthetic-stabilized base layers

Reduced-scale pavement test sections, with and without geogrid-stabilized base layers, were constructed and trafficked using a model Mobile Load Simulator (MLS11) to evaluate the mechanism of geogrid stabilization of unbound aggregate bases. The performance of the pavement sections was evaluated by measuring vertical surface displacements (rut), horizontal particle displacements within the base, and vertical stresses within the pavement structure. Two control sections, identical in their construction and configurations, were initially evaluated and found to produce repeatable performance, within 10% of each other, in terms of surface rutting, and horizontal particle displacements within the base. A geosynthetic-stabilized section, constructed with geogrid within the aggregate base, showed a 230% increase in traffic capacity compared to the control section at the same failure rut. The stabilized section also showed a 30% reduction in internal vertical stress at the middle of the base and a 17% reduction at the base-subgrade interface. The presence of the geogrid decreased the particle-to-particle shear transfer across the geogrid, which was observed as a reduction in particle displacements below the geogrid. The geogrid provided lateral restraint to offset the reduced shear transfer, the effects of which were observed from the redirection and reduction of lateral flow in the vicinity of the geogrid. The particle tracking sensors presented in this study proved to be a valuable tool to visualize the effect of lateral restraint provided by the geogrid, aiding understanding of this mechanism.