Low volume road damage—load and environmental factors

Abstract

This research aimed to provide reliable evidence on the wear characteristics of New Zealand local road pavements from accelerated pavement loading studies at the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF) to complement existing CAPTIF data on State Highway strength roads. The two ‘vehicles’ at CAPTIF were configured with identical suspensions but with different axle loads. Three different pavements tests were conducted at CAPTIF with each test using the same subgrade but two different aggregate types and two thicknesses. The aim was to determine the relative damage on different pavement types/strengths to inform the loading component of the road user charging model used in New Zealand. The data was extended with rut depth modelling and validated with field data and suggests that the load damage exponent increases as pavement life decreases. The study has confirmed that the widely-accepted 4th power law is sometimes a gross simplification of pavement wear.