Geogrid Reinforced Base Courses for Flexible Pavements for Light Aircraft: TestSection Construction, Behavior under Traffic, Laboratory Tests, and Design Criteria

摘要

The results of a literature review investigating geogrid reinforced base coursesfor flexible pavements for light aircraft and the design of a geogrid test section for field testing the validity of potential geogrid reinforcement results have been previously reported. The construction of the field test section, the behavior of the test section under traffic testing using a 30,000 lb single tire load, the data collected, laboratory tests that were conducted on the various geogrid products used in the field test section, and development of design criteria for geogrid base reinforcement for flexible pavements for light aircraft are described. Test results verified the validity of geogrid reinforced base courses for flexible pavements for light aircraft. A geogrid reinforcement product equivalent to the SS-2 geogrid used in the field tests can reduce the total pavement design thickness. The geogrid performance is a function of depth of placement. The thickness reductions range from approximately 40 percent for unreinforced pavement thicknesses of 11 in. to 5 percent for 20-in.-thick pavements. The geogrid reinforcement performs best when placed between the base course and subgrade. The improvement mechanisms for geogrid reinforcement include grid interlock with aggregate base material, subgrade confinement, and to some extent a tensioned membrane effect. The geogrid property requirements for optimum performance are not totally known at this time. The performance of the various geogrid products tested ranged from no improvement up to a 40 percent reduction in total pavement thickness requirement. A relatively rigid sheet-type product (SS-2) performed the best.