Full Scale Highway Load Test of Flexible Pavement Systems with Geogrid Reinforced Base Courses

The use of geosynthetics to improve the performance of flexible pavements has increased significantly over the last decade. This paper describes a full scale testing research program that used a 20 kN moving wheel load to determine the benefit of using a stiff biaxial geogrid between the base and subgrade of a flexible pavement system. The traffic benefit ratio (TBR) was defined as the ratio of the number of load cycles of a stiff geogrid reinforced section, to the number of load cycles of an unreinforced section for a given level of performance. The TBR values ranged from 2 to over 10 for the conditions tested. Traffic benefit ratio values between 2 and 4 appear to be reasonable for use in pavement design.