THE PERFORMANCE OF REINFORCED UNPAVED SUB-BASES SUBJECTED TO TRAFFICKING

Geosynthetics are used in pavement construction to reinforce the sub-base layer, when the underlying material is weak, or when the thickness of the pavement needs to be kept to a minimum. However, the effectiveness of this technique is difficult to quantify and is best investigated by undertaking full scale Trials. Trafficking Trials have been carried out in the Pavement Test Facility at the Transport Research Laboratory (UK) to assess the ability of a range of different geosynthetic reinforcements to reduce the surface deformation of an unpaved road. Twelve different reinforcements were included in the Trials; these included integral grids (punched and stretched or, extruded grids, woven grids, bonded junction grids, composite grids and woven geotextiles. The performance of the reinforcements was quantified in terms of pavement stiffness, and surface deformation of the sub-base. This paper present details of the test facility, methodology and the principle results. The relations between deformation under the wheel path with the number of wheel passes are presented. The results are compared with the standard unpaved road design equation derived by Giroud and Noiray. (A)