Structural Contribution of Geosynthetic-Reinforced Working Platforms in Flexible Pavement

Abstract

A study was conducted in the field and with a large-scale model experiment (LSME) to evaluate the structural contribution of a 0.30-m-thick geosynthetic-reinforced granular layer used as a working platform for construction over soft subgrade. The study was conducted in the context of the 1993 AASHTO design guideline, in which the structural number (SN) of the pavement is based on layer coefficients (each defined using a resilient modulus). Working platforms reinforced with geosynthetics had smaller elastic deflections and larger elastic moduli than unreinforced working platforms with the same thickness. Reinforcement factors obtained in the field ranged from 1.2 to 1.8; those obtained in the laboratory ranged from 1.7 to 2.0, with greater reinforcement factors for the less extensible geosynthetics (geogrid, woven geotextile) for a 0.3-m-thick granular working platform. Of the four geosynthetics tested, the geogrid resulted in the greatest increase in modulus. Reinforcing the working platforms with geosynthetics resulted in increases in layer coefficients ranging from 50% to 70%. Similarly, increases in SN for a typical pavement structure were realized, ranging from 3% to 11% when all other factors were equal.