Stiffness Reductions of Flexible Pavements due to Cumulative Fatigue Damage

Abstract

A new asphalt layer modulus degradation model for use with flexible-pavement analysis procedures is described. The model is capable of determining the reduction in stiffness of the asphaltic material in a flexible pavement due to cumulative fatigue damage. Measured surface deflection bowls from a number of test pavements are used with a pavement parameter back-calculation procedure, to determine the reduction in stiffness of the asphaltic material throughout the life of the pavement. Results show an exponential relationship between the reduction in asphalt layer stiffness and cumulative fatigue damage. This type of relationship does not agree with an earlier theoretical continuum damage mechanics model, where the relationship between the reduction in asphalt layer stiffness and cumulative fatigue damage was predicted to be linear.