Performance of Geotextile Separators Five Years after Installation

Abstract

During the reconstruction of a state highway in 1991, a full-scale test section was established at a site with a history of poor pavement performance, most likely because of a soft silty clay subgrade, high ground-water table, and heavy logging truck traffic. Five different separator geotextiles and a soil-only control section were installed in each lane. Excavations were made in the test section 5 years after installation, and samples of geotextiles, subgrade, and base course materials were exhumed for visual observation and laboratory testing. In addition, in situ soil tests were performed on the exposed subgrade soils. This paper summarizes these observations and test results. Although some fines from the subgrade had migrated through the geotextiles into the bottom of the base course, there was no evidence after 5 years of any adverse effect on the pavement itself. Minor geotextile damage that apparently occurred during construction had little effect on the pavement performance. In all of the sections with geotextiles, the subgrade soils were found to have consolidated significantly in comparison with the soil-only sections. Overall, the geotextiles performed their intended function well.