Experimental estimation of the relative deterioration of flexible pavements under increased axle loads

Abstract

The deterioration of Australia's unbound granular pavements with a wearing surface of stone aggregate embedded in a thin bituminous binder seal is likely to increase with increases in axle loads due to the predicted doubling of the freight task carried by heavy vehicles travelling interstate over the next 15 years. Experimental pavement deterioration data gained from accelerated load testing (ALT) were used to derive relative performance factors for rutting and roughness deterioration for increases in axle loads. The ALT involved applying increased axle loads to test pavements in an enclosure that maintained a constant environment. The relative performance factors can be applied to the observed deterioration of pavements under known levels of axle loading to develop network-level road deterioration (RD) models that predict the influence of increased axle loads on deterioration. Several long-term pavement performance studies have collected observational data for this purpose of network RD model development.

Keywords:

• network pavement deterioration
• relative deterioration for roughness and rutting
• load damage exponent
• sealed granular unbound pavements
• accelerated load testing

Acknowledgements

The author would like to acknowledge the funding support from Austroads for this research and the technical advice received from Prof. William Young of Monash University, Mr Thorolf Thoresen of the ARRB Group and Dr John McLean, an independent consultant.