Visual Inspection Based Maintenance Strategy on Unsealed Road Network in Australia

Abstract

Gravel loss on unsealed roads is financially a major setback for all road agencies. The maintenance strategy in Australia is primarily based on visual inspection only which has inherent drawbacks. It is also environmentally unsustainable. Key challenges associated with the unsealed road management are identified as (i) difficulty to forecast behaviour, (ii) significant data collection needs and (iii) vulnerability in level of service & maintenance practices. The quality of gravel material is one of the major influencing factors. Various theoretical models have developed in the past to estimate gravel loss. These studies are used to estimate road deterioration and maintenance strategy in practice. A range of approaches such as regression analysis of field measured data, system dynamic modelling approach, laboratory measurements have been employed in the past. In the state of Queensland of Australia, the long-term gravel loss monitoring is planned in the region affected by frequent flood to assess the amount of gravel loss and associated maintenance issues. Recently, a mammoth maintenance work was undertaken on unsealed road network to cater for gravel loss due to Ex Tropical Cyclone Debbie. Visual inspection can be a useful tool to provide snapshot of unseal road network at a time. Most road agencies still use this visual inspection as a maintenance strategy tool. It is recommended in this study to integrate visual inspection with localised gravel loss model and roughness data. GPS based data can be integrated by using visual inspections, roughness and the gravel model.