FIELD VERIFICATION OF GEOGRID PROPERTIES FOR BASE COURSE REINFORCEMENT APPLICATIONS (FHWA-OK-13-11 2244)

Abstract

The proposed field study is a continuation of a recently concluded, ODOT-funded project titled: Development of ODOT Guidelines for the Use of Geogrids in Aggregate Bases, which is aimed at addressing the need for improved guidelines for base reinforcement applications. One important objective of this long-term study is to develop a correlation between the index properties of geogrids and their field performance for base reinforcement applications. The index properties that will be studied include the junction strength, low-strain rib strength (i.e. strength at 2%-strain and 5%-strain) and the ultimate rib strength of selected geogrids. The project will involve the selection of a full-depth roadway construction project authorized by ODOT. During the construction of the road subgrade, one test section will be used to examine and compare the performance of selected base course reinforcement geogrid products. The field performance of different geogrids will be monitored using different instruments and monitoring techniques and compared with one another as a function of their index properties. Selected instruments include Earth Pressure Cells (EPC) to measure the stress on the subgrade underneath the geogrid, pore pressure transducers to measure the pore pressure in the subgrade and strain gauges to measure the tensile strength of the different geoshyntetics. The results of this study will help ODOT to develop an improved and expanded set of materials specification guidelines for the use of geogrids in aggregate base reinforcement applications. The outcome of this study will help ODOT and other transportation agencies in the U.S. develop more durable and economical aggregate base designs which will result in longer service life and reduced maintenance costs for the roadways in Oklahoma and across the United States.