Austroads has published a modelling framework, supporting tool and compilation of case studies to help road asset managers evaluate and select effective road preservation and renewal treatment options.
Ross Guppy, Austroads Transport Infrastructure Program Manager said that while the framework focusses on flexible sprayed seal pavements, it can be applied to other pavement types.
“Road asset managers are regularly required to justify decisions about the timing and type of road surfacing and rehabilitation treatments applied across their networks,” Guppy said.
“Choosing inappropriate treatments and their timing can increase road safety risks, reduce the level of service provided to the community and add significant costs in the long term.”
The framework is based on applying whole-of-life-cycle costing and economic measures to identify solutions which minimise total transport costs. It covers a 50-year analysis period to account for the fact that road pavements in Australia and New Zealand are long-life assets, remove the need for the determination of residual value of the assets and to be able to analyse future improvements to a network.
The scenarios considered in the framework were developed using road agency national and regional data and research from Austroads’ previous studies.
To apply the framework to guide the development of strategies and works programs, a new analysis tool was developed. Termed the pavement life-cycle cost demonstration tool (PLCCDT), it covers the full range of road operating conditions, performance issues and solutions. The tool also includes supporting road deterioration (RD) and works effects (WE) models from previous Austroads research.
“The tool examines and compares different maintenance scenarios over a user-selected project length of pavement and provides various treatment options without the need to use the optimisation software,” Guppy said.
The following can be investigated by the PLCCDT:
- holding treatment options including shape correction treatments, representing rut filling and major patching, and resurfacing options that address functional performance and extend pavement life
- pavement and surfacing treatments which address high levels of cracking, rutting, roughness and deflection that reflect inadequate structural capacity to extend pavement life.
The framework is accompanied by a suite of case studies that demonstrate the use of the tool. The examples represent cases from New South Wales, Queensland, Victoria and Western Australia and build on real-life observations reflecting a variety of design, environmental and operating conditions, including the types of road pavement, traffic levels and proportion of heavy vehicles which use the networks.
The impact of supporting treatments such as drainage provision and maintenance and shoulder sealing which can enhance pavement performance is not an in-built feature of the tool. These can be represented through applying different model calibration factors to control deterioration and works effects which is expected to be supported by performance evidence.
Concrete pavements and unsealed roads were not in scope for this project.
To download the report and tool, click here.