Rutting of flexible pavement structures when submitted to repeated heavy-vehicle loading is a complex phenomenon. In northern environment where thick granular layers are included in flexible pavement structures to reduce frost action, most of surface rutting occurs in unbound granular materials. This long-term permanent deformation damage can be studied with heavy vehicle simulator. A small-scale laboratory heavy vehicle simulator was developed at Laval University over the last few years and this paper presents the first results obtained for the characterization of the rutting behavior of flexible pavement bases. Standard aggregate bases, as well as base layers containing 70 % RAP and geogrid were tested. The results obtained are in good agreement with literature on permanent deformation and geogrid reinforcement. The rutting sensitivity of RAP bases is compared to standard aggregate base layer and the structure behavior improvement caused by the geogrid is also quantified.