The benefits of stabilisation geogrids in whole pavement construction

Abstract

Research into the behaviour and effect of including geogrids in the unbound layers of roadways has been carried out over the last 30 years. It has led to an understanding of how the performance benefits observed can be quantified and applied by engineers to reduce the unbound layer thickness, cut construction costs and increase traffic life. So far, highway applications of geogrids have tended to be limited to where problem soils have been encountered along the route. However, extensive research programmes into hexagonal structure geogrids have extended the application of geogrid benefits to the design and construction of the whole pavement, offering savings in the bound layers as well as unbound layers. This paper reports on trafficking trials carried out in the UK and USA at both small and full scale. Using project case studies, it describes how the inclusion of a geogrid in the granular layers of a whole pavement can reduce project costs while maintaining traffic life, increase project life to reduce maintenance and rehabilitation costs, and increase project value for clients.