Design System for Asphaltic Concrete Overlays

A method of designing asphaltic concrete overlays has been developed from (1) Kentucky\u27s 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