A new approach for modelling rutting on the New Zealand State Highways

Abstract

Previous research using the World Bank’s HDM rutting models has highlighted limitations when used to model rutting on New Zealand State Highways. Consequently, this research was aimed at delivering a new model format to predict rut progression for New Zealand conditions. Data from both the Long-Term Pavement Performance (LTPP) program and the New Zealand Transport Agency (NZTA) CAPTIF program was analysed in the research. The outcome of the research is a three-stage modelling approach. The first is a simplified model to predict the initial densification. The second is a linear model to predict the progression of rutting during the stable rut stage. Finally, a third model is used to predict the probability of a pavement undergoing accelerated rut progression associated with failure of the pavement. A major benefit that the new proposed model system promises is its simplistic format, which makes it easy to adopt into a pavement-management system. The resulting models are also more robust for New Zealand conditions. However, like all empirical models they should be used only on the networks from which they were derived.