ABSTRACT
Although concrete overlay on deteriorated asphalt pavement techniques have been used for many years with satisfactory results, thickness restrictions limit the use of this method. On the other hand concrete inlay techniques providing equal thickness before and after rehabilitation have not been very successful since continuity and co-operation of both layers cannot be achieved. The Ultra Thin Whitetopping inlay technique provides good results although equal thickness can be achieved through the use of small concrete height. The thickness is justified by the use of very close joint spacing, the composite action of concrete and asphalt as one layer and the use of high quality concrete possibly with additions. The technique provides a fast, durable, rutting free and price competitive pavement. Since the technique is relatively new, only few design rules exist and these are mostly of empirical nature. The paper describes the results of a two dimensional finite element parametric calculation for this pavement type. The results indicate that maximum eccentric loading provides the maximum tensile concrete stresses and joint loading provides the maximum asphalt tensile stresses. However the results of asphalt and concrete are interdependent and both layers cannot be designed independently. Furthermore when designing this pavements much attention needs to be put on the side support which has a substantial influence on the concrete stresses. The extension of the supporting layers on both sides of the top layers seems dominant to this dependence but frequently unknown to the owner. Maybe the results of this study will contribute to the further development of design techniques for this promising method.
