Chapter 10: Paved roads and runways

Geosynthetics are used in paved roads and runways to provide reinforcement, separation, drainage and filtration. Common geosynthetics used include geotextiles, geogrids, geonets and geocomposites. Geosynthetics help control the development of common pavement distress features such as rutting and cracking. This is accomplished by structural reinforcement of the base aggregate layer, controlling infiltration into moisture-susceptible layers, and preventing contamination of structural layers by the migration of fines from underlying soils. These functions help preserve and, in some cases, enhance the structural integrity of the constructed pavement layers. In this chapter, the functions listed above are described and illustrated for paved roads and runways. Guidelines for the selection and use of geosynthetics for paved road reinforcement are presented. These guidelines currently rely upon the use of a traffic benefit ratio or a base course reduction ratio. These parameters are dependent on the geosynthetic used and the design-specific roadway materials and layer thickness. The ratios may be determined by constructing test sections incorporating these conditions or by methods incorporating mechanistic-empirical design principles.