ASPHALT OVERLAY DESIGN FOR AIRFIELD PAVEMENTS

This paper describes how overlay pavements are designed to increase the load-carrying capacity (strength) of the existing pavement. The basis for design is to provide a layer or layers of material on the existing pavement that will result in a layered system, which yields the predicted performance of a new pavement if constructed on the same foundation as the existing pavement. Strengthening is required when heavier aircraft are introduced or when a pavement is no longer capable of supporting the aircraft loads for which it was designed. Two types of overlay pavement are considered-rigid and nonrigid. The procedures described in this paper are limited to nonrigid overlays to strengthen existing rigid or flexible pavements. Nonrigid overlays include both flexible (nonstabilized base and asphaltic concrete (AC) wearing course) and all-AC for strengthening existing jointed concrete (JC) or jointed reinforced concrete (JRC) pavements. The paper discusses how specific procedures must be followed to determine if a pavement requires strengthening or other rehabilitation.