This report describes the evaluation of enrobé à module élevé (EME), a very high stiffness roadbase material, whose use in France justifies reductions of 25 to 40 percent in the roadbase thickness compared to the traditional French roadbase, grave bitume. Following a study visit to France to gain more information on aspects of material design, manufacture and construction practice, a demonstration trial was arranged at TRL to further evaluate the potential of this material and determine whether any special practices are essential. This trial also provided the opportunity to examine whether UK dense bitumen macadam could be modified to produce a material with structural properties similar to EME. properties similar to EME. The study concluded that very high stiffness roadbase materials have considerable potential in more economic forms of road construction. No more difficulties were encountered in mixing, laying and compacting the high stiffness materials than would be expected with standard materials. Dense bitumen macadam roadbase to the current UK specification was successfully modified using a 15 pen binder and shown to have properties very similar to EME and this material should be introduced on a trial basis so that its performance properties can be confirmed. (A)
Abstract