A method of designing asphaltic concrete overlays has been developed from (1) Kentucky's theoretical design curves, (2) an estimate of future traffic and the associated fatigue (five procedures are presented according to types of information available), (3) strength of subgrade on subject project (laboratory CBR tests or results of dynamic in-place tests such as the Road Rater), and (4) present condition of the existing pavement (from dynamic in-place tests, roughness measurements, or present serviceability index). Deterioration has been expressed as reduced or effective thicknesses of new-quality materials producing the same measured dynamic deflections. The total thickness required for the future traffic minus the effective or reduced thickness of the existing pavement is the overlay thickness required.

Report Date


Report Number

No. 511

Digital Object Identifier



The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Bureau of Highways nor of the Federal Highway Administration. This report does not constitute a standard, specification, or regulation.