Base Reinforcement with Biaxial Geogrid

Abstract

In 1986 and 1990, the Georgia Department of Transportation constructed two pavement test sites to evaluate the performance of pavements with base reinforced with biaxial geogrid. The evaluations were conducted by a comparison of results from two control sections with no base reinforcement with the results of three test sections with base reinforced by geogrid placed at different depths of the base layers. The test sections also incorporated reduction of pavement section thickness with the use of geogrid. To determine the effectiveness of the geogrid application in regard to pavement cracks, rutting, and deflections, field evaluations were performed on the test and control sections shortly after construction. Construction on SR-155, Henry County, the first test site, ended in 1986; in 1987, the first evaluation was conducted. Annual evaluations were continued up to 1991. At the second test site, East Rome Bypass in Floyd County, construction ended in 1990. Baseline evaluation data were taken soon after construction and in 1991. The tests consisted of deflection measurements, rut measurements, and crack surveys. It was found from these short-term evaluations that the levels of pavement performance for the test and control sections were almost the same. The pavement sections and subgrades at both test site locations were strong and appeared to have a significant effect on the pavement performance. The thinner test sections reinforced with geogrid provided a comparable level of pavement performance to the control sections. Further long-term evaluations were performed in 2005 to determine the performance of the pavements. These evaluations included pavement condition surveys and falling weight deflectometer runs. It was concluded that geogrid test sections with less thickness appeared to perform as well as the typical control sections.