THEORETICAL RESPONSE OF MULTILAYER PAVEMENT SYSTEMS TO DYNAMIC NONDESTRUCTIVE TESTING.

Nondestructive testing of highway and airport pavements has become increasingly popular. Although dynamic loading devices have become the method of choice because their field operation is relatively simple, fast, and economical, analysis of the test data remains problematic. Using a rigorous elastodynamic formulation, it is demonstrated in this paper that the dynamic phenomena of resonance and inertial damping within the subgrade may result in significant differences in pavement response to static and dynamic loading. Because static analyses are currently used to analyze the latter, significant errors may arise in back-calculating layer stiffnesses. Examination of the data obtained from a study of the response of four-layer flexible pavements to excitation by the Road Rater device for a wide range of frequencies suggests that no simple correlation between dynamic and static deflections can be developed.