Mechanistic analysis and design approach for geosynthetic stabilized pavements

Abstract

Geosynthetics provide mechanical stabilization benefits to constructed pavements through well-established mechanisms of lateral restraint of unbound aggregate particles and bearing capacity improvement over weak subgrades. State-of-the-art techniques to incorporate geosynthetics into pavement design and construction essentially involve conducting proper elastic layered system mechanistic analysis to determine the amount of reduction in aggregate layer thickness. This paper presents a mechanistic analysis and design framework for determining the required aggregate base thickness through experimentally determined aggregate modulus enhancement in geosynthetic-stabilized pavements via the finite element (FE) modelling approach. An advanced FE analysis tool, C-FLEX, recently developed for the US Army Engineer Research and Development Center, was employed to analyze axisymmetric multi-layered flexible pavement structures, accounting for the stress-dependent, nonlinear behavior of unbound aggregate base. Modulus enhancements, quantified for ten different geosynthetic products through Bender Element (BE) sensor technology in triaxial testing of geosynthetic-stabilized aggregates, were incorporated into the base modulus characterization. Instead of explicitly modelling geosynthetic components, their benefits were captured in mechanistic analysis via a sublayering approach, which integrates both the measured enhanced modulus and extent of geosynthetic influence zone. Design scenarios were developed for typical low-volume roads with thin asphalt surface treatment over soft subgrade. Reductions in base course thicknesses with the different geosynthetics were reasonably accounted for using the proposed framework, which provides a mechanistic- based approach to stabilized pavement design with any geosynthetic product.