Geosynthetics in unpaved Roads

Inclusion of geosynthetics has been proved to be very effective in providing additional support and good rideability in roads. This paper presents results from laboratory model studies and field studies carried out on unreinforced and reinforced unpaved low volume roads sections constructed over weak subgrade. The relative advantages of placing different reinforcing materials like geotextile, biaxial geogrid and geocell layer at the interface of subgrade and base course are studied in terms of increase in load carrying capacity and reduction in rut depth. In laboratory model studies to simulate wheel load, repeated load is applied manually through a hydraulic jack whereas in field studies the moving vehicle load is simulated by the passage of a scooter on the road at uniform speed for a maximum of 250 passes. The experimental and field test results are analysed and compared to understand the relative efficiency of each of these reinforcing materials in reducing the settlement/rut formation in unpaved roads. Effectiveness of geocell layer compared to planar geotextile and geogrid layers in terms of increase in load carrying capacity and reduction in deformations is also studied.