This report describes a trial carried out in the Pavement Test Facility at TRL to assess the performance, under repeated loadings of a moving wheel, of off-site recycled Heavy Duty Macadam (HDM) roadbase incorporating 50 per cent of reclaimed material in the mix. The trial also included a section of conventionally produced HDM, laid at the same time as the recycled material, to act as a control against which the performance of the recycled material could be evaluated. In-situ measurements were made, on the subgrade, subbase, roadbase and wearing course to assess the variability in the structural strength of each pavement layer and that of the finished structure. During trafficking the rate of formation of permanent deformation and rutting caused by repeated applications of a loaded moving wheel were recorded together with measurements of dynamic strain generated in the subgrade. Periodic measurements were taken with the Falling Weight Deflectometer to monitor pavement deflection and modulus. Samples of both materials were taken from the compacted pavement for laboratory determination of elastic stiffness, resistance to permanent deformation and composition analysis.

Want to know more about this project?