Mechanical Stabilization of Unbound Layers to Increase Pavement Performance and Incorporation of Benefits into M-E analysis

Abstract

In recent years there has been a growing body of evidence supporting the performance benefits of incorporating stiff geogrids into unbound road base layers to improve the mechanical properties of the layer with a resulting improvement in pavement performance. This is quite distinct from the common use of geogrids in many countries for the construction of road foundations over weak soils. This paper will review the research evidence supporting the use of geogrids in a stabilization capacity to improve the modulus and subsequent performance of unbound layers by controlling particle movement and reducing deformations. Guidance published by AASHTO recommends that pavement designs incorporating the effect of a geosynthetic need to be based upon experimentally derived input parameters that are often geosynthetic specific. Such an experimental based approach is described in the paper. A description is provided of the steps taken to incorporate the geosynthetics effects into M-E pavement analysis.