Construction, instrumentation and field performance of geogrid-reinforced unpaved roads Available to Purchase

A research study involving full-scale unpaved road test sections was carried out to investigate the performance of unpaved roads reinforced with geogrids. Ten test sections were constructed with two different base course thicknesses. Three biaxial geogrids of different tensile stiffness and one geogrid with triangular aperture were evaluated. Geogrids were placed at the subgrade–base course interface. The sections were instrumented for measuring road response to traffic loading. Traffic loading was provided by a single-axle dump truck. Field measurements of rut depth and surface deformation were recorded at selected traffic intervals. An analysis of the measured performance data indicated that the geogrids effectively reduced surface rutting and improved the performance of unpaved thin base layers and the benefit became more pronounced when a stiffer geogrid was used. The results suggested reductions in the thickness of the base layer by using geogrids of up to 18%. The improvement by geogrids was shown to be less for increasing base layer thickness. In addition, the ability of the design procedure by Giroud and Han to predict rutting performance using the test section parameters as design inputs was assessed. The results indicated that the method underpredicted the required base thickness to support the applied traffic loads.