Quantifying the Influence of Geosynthetics on Performance of Reinforced Granular Bases in Laboratory

Abstract

Interaction between geosynthetics (geogrid and geotextile) and aggregates under traffic wheel loading has been considered as one of high-priority problems by the U.S. Transportation Research Board. The practical use of geosynthetics above a subgrade or within a base course has demonstrated the benefit of reducing rut depths and prolonging pavement life. However, no standard test method is available to appropriately evaluate the geosynthetic-soil confinement effect and distinguish the benefits of the different types of geosynthetics and soils. This paper provides an overview of existing test methods and outlines the advantages and disadvantages of each method. The newly developed test method by the authors is performance-based and modified from the Asphalt Pavement Analyzer to evaluate geosynthetic-soil confinement. In this test, a geosynthetic sheet is placed within a base course to form a reinforced base, which is subjected to wheel loading. The measured rut depth with the number of cycles of wheel loading can be used to evaluate the geosynthetic-soil confinement. In this study, two different base course materials and four different geosynthetics were used. The experimental results clearly show that this newly developed performance-based test method can distinguish the benefits of rut reduction among different types of geosynthetics and base course materials. The experimental tests of geotextile-reinforced bases were analyzed by a two-dimensional discrete element method. The limitations of this experimental method are also discussed.