An alternative roughness index to IRI for flexible pavements

Abstract

The International Roughness Index (IRI) is widely accepted as a measure of pavement condition. However it was developed as an indicator of passenger comfort as they travel in a vehicle on the pavement. In this paper, for the assumed failure model adopted, IRI is not found to be a good indicator of remaining pavement service life. The 3D continuous wavelet transform is proposed and shown to be a more effective indicator. Specific scales related to natural frequencies of the vehicle fleet, particularly the body mass frequency, are more significant than others. A weighted mean of the wavelet coefficients for these scales is used as an indicator of remaining life. One hundred randomly generated class A profiles are generated and their histories of damage progression throughout their lives are simulated. The new indicator is applied to the initial profiles to determine which ones are more vulnerable to damage than others. In numerical simulations using the assumed damage model, the wavelet based indicator is shown to be well correlated with service life.