Austroads: Transport Research and Trends

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Investigation of Pavement Assessment Methodologies for PBS Access

We rely on road freight transport to keep Australia’s economy moving. Performance Based Standards (PBS) vehicles, that are typically longer and heavier, do this work more efficiently but how much road damage do they cause in the process?

This webinar, presented by Anthony Germanchev, Georgia O’Connor and Angus Draheim, explores the methods used by road managers to answer this question. It proposes a framework to support consistent approaches to understanding and comparing the pavement impacts of PBS vehicles. Some of the key steps government agencies are taking to support road managers in assessing PBS vehicles for network access are also outlined.

National Specification for Crumb Rubber Binders in Asphalt and Seals

Australia and New Zealand produce about 510,000 tonnes of end‑of‑life tyres annually. Crumb rubber derived from end‑of‑life tyres has been used in Australia for several decades to enhance the performance of binders used in sprayed seals but prior to 2017 the use of crumb rubber in asphalt pavements was limited.

Due to the lack of crumb rubber binder grades suitable for use in asphalt in the Austroads national polymer modified binder (PMB) specification (ATS 3110), two Australian jurisdictions and the Australian Flexible Pavement Association recently developed specifications for crumb rubber binders for use in asphalt which were based on tests and testing protocols used in Arizona and California.

This webinar, presented by Robert Urquhart, focuses on the outcomes of an Austroads research project which investigated whether the crumb rubber binders that were trialled in asphalt could be specified in terms of the tests and testing protocols used to specify other types of PMBs in the Austroads national PMB specification. Specification requirements have also been proposed for a binder containing 9% crumb rubber by weight which could be used in sprayed sealing applications.

The webinar also discusses the results of laboratory asphalt performance tests which investigated the effects of the amount of crumb rubber in a binder on asphalt performance.

Evaluating the Rutting Performance of Binders

Asphalt pavements are a major component of the Australian and New Zealand road networks. Road agencies in Australia and New Zealand have been putting great efforts to produce pavements which perform and are long-lasting. This has led to the development of national specifications to ensure materials of suitable quality are used for road construction.

Austroads ATS 3110 is used as a national performance-based specification for polymer modified binders (PMBs). The specification includes the consistency 6% (at 60 °C) property to evaluate the relative performance of a binder to resist rutting, as it is one of the major failure modes of asphalt pavements.

Consistency 6% tests are currently conducted using the elastometer instrument that was developed in Australia specifically for these tests. This instrument, however, is no longer being manufactured and the supplier is no longer providing technical support for existing instruments. A new test method has therefore been developed to determine consistency 6% properties using a dynamic shear rheometer (DSR) rather than the elastometer. The DSR is widely used to test bituminous binders and other materials across the world.

Presented by Young Choi, this webinar details the outcomes of the Austroads research project which was conducted to develop the DSR consistency 6% test method. The project work included an extensive literature review, equipment investigations, optimisation of test procedures and validation studies using many different types of binders. These studies were conducted to ensure that the new DSR test method is equivalent to the current elastometer test method.

Use of Recycled Plastics in Road Surfacing

The ban on the export of recycled waste plastic by the Australian government has led to interest in the use of recycled waste plastic in road surfacing applications. Austroads has published a report, Interim guidelines for the use of recycled waste plastic in local government road surfacing applications, to assist local government in the use and procurement of road surfacing products incorporating recycled waste plastic.

This webinar, presented by Azeem Remtulla and Steve Halligan provides key information from the interim guidelines, discusses the status of the use of recycled waste plastic in road surfacing applications, the methods for the addition of recycled waste plastic into bituminous binders and asphalt along with limitations on the use of recycled waste plastic and proposes a methodology to the procurement of products incorporating recycled waste plastic.

The webinar also discusses surfacing applications for local council roads and propose a framework for comparing the properties of conventional asphalt to alternative asphalt mixes containing recycled waste plastic. This framework is based on current state road authority (SRA) and local government asphalt specifications and includes proposed tests to compare the performance properties of conventional asphalt against alternative asphalt mixes.

Worked hypothetical examples of the procurement and assessment process for asphalt incorporating recycled waste plastic as an alternative to conventional asphalt are also shared.

Technical Basis of Changes to Guide to Pavement Technology

Austroads has published two technical reports drawing together the research underpinning changes made to key components of the Guide to Pavement Technology.

The reports detail the technical basis for changes made to Guide to Pavement Technology Part 2: Pavement Structural Design and Guide to Pavement Technology Part 5: Pavement Evaluation and Treatment Design.

This webinar, presented by Dr Michael Moffatt and Dr Geoff Jameson, outlines the technical basis of the changes made to Parts 2 and 5 since the last versions of the technical basis reports were published in 2008.

The 2017 edition of Part 2 included improvements to the design of flexible pavements, significant revision to the procedures used to calculate the design traffic, new procedures for the design of pavements with lime-stabilised subgrades and improved methods to predict the in-service fatigue life of cemented materials and estimate asphalt and cemented material design moduli.

The Guide to Pavement Technology Part 5 provides guidance on the selection and design of strengthening treatments to rehabilitate pavements. This is an integral part of managing a road network. The most recent edition of the guide enhanced the design procedure and expanded its use to a broad range of strengthening treatments, including asphalt overlays, inlays, major patchings and stabilisation of pavement layers and subgrade. The procedure is identical to the mechanistic-empirical procedure for the design of new pavements (detailed in Part 2) with the addition of an initial phase which determines the properties of the materials in the road-bed.


Austroads Project Pipeline 2021-22

This webinar provides an overview of Austroads’ projects 2021-22 and what is required to work with Austroads.

The session is beneficial to consultants who may be interested in tendering for Austroads projects.

The projects discussed focus on data collection and management, digital engineering, tunnel design and componentry, bridge assessment, pavement technology, road design, road safety audits, driver licensing, environment reporting, and vehicle and infrastructure connectivity.

The webinar is presented by Paul Davies, Austroads Acting General Manager Operations, and program managers:

  • Ross Guppy, Program Manager Transport Infrastructure
  • Michael Nieuwesteeg, Program Manager Road Safety and Design
  • Richard Delplace, Program Manager Transport Network Operations
  • Vibeke Matthews, Acting Program Manager Future Vehicles and Technology, and Environment and Sustainability Program.

Strategy for an Improved Mechanistic-empirical Flexible Pavement Treatment Design

Following the update of the Austroads Guide to Pavement Technology Part 5: Pavement Evaluation and Treatment Design in 2019, Austroads commissioned the development of a strategy for future improvement of the mechanistic-empirical procedure (MEP) used in pavement rehabilitation and strengthening treatment design.

This webinar, presented by Dr Didier Bodin and Dr Geoff Jameson, outlines future research direction derived from the review of national and international literature and road agency best practice. Priority areas were identified through engagement with pavement designers across road agencies and industry. The main topics presented include:

  • Methods to characterise past and future fatigue damage of existing bound pavement layers.
  • Design method to quantify the extent of reflective cracking in treatment layers.
  • Enhanced use of traffic speed deflectometer data.

The roadmap for short, medium and long-term strategy will inform future research program towards providing pavement designers with improved pavement rehabilitation design procedures in the near future.

The webinar also discusses practical aspects of the pavement and subgrade layers moduli back-calculation from measured surface deflections.

Next Generation Asset Data Collection: Road Pavement Performance

The increasing pace of change of technology brings considerable promise of more data, of a higher quality, captured for a lower cost. This has the potential to improve the asset management of roads by enabling better decision making and providing a more complete picture of asset performance.

These benefits, however, are not automatic. For asset managers, it can be difficult to know what technology is available and how the benefits compare to costs. There is also often considerable friction in moving to new approaches as existing processes and systems are tailored for the status quo. Perhaps the biggest hurdle is confidence in moving from an existing approach to having trust in the unknown.

In response to this need to understand the emerging technologies available, the cost-effectiveness of these technologies, and the implications of transitioning from existing to new approaches, Austroads has developed a research report on next generation data collection technologies for road pavement assets.

With specific reference to road pavement assets, this webinar takes attendees through:

  • The key themes across the data required to inform asset management decisions.
  • The current state of data collection technologies.
  • The interconnected ecosystem of emerging data collection technologies.
  • A structured framework for evaluating the cost-effectiveness of emerging data collection technologies.
  • Insights from the application of the evaluation framework and implications for future approaches to data collection.

Presented by David Jansen, Susan Chamberlain, Ella Hingston, Dr Colin Kemp and Trevor Chiang.

Development and Justification of Asset Preservation and Renewal: Investment Decision Making

This is a final session in the series of three webinars based on the Austroads report Prolonging the Life of Road Assets Under Increasing Demand: A Framework and Tools for Informing the Development and Justification of Asset Preservation and Renewal.

It is presented by Tim Martin, Tyrone Toole and Qindong Li, and explains the broad framework and the economic and customer centred basis for justifying appropriate levels of investment in road asset preservation and renewal. Examples include those which impact strategic, network level decisions and supporting policies and processes.

Development and Justification of Asset Preservation and Renewal: Framework and Tools

This is the second session in a series to present the findings of Prolonging the Life of Road Assets Under Increasing Demand: A Framework and Tools for Informing the Development and Justification of Asset Preservation and Renewal.

The webinar, presented by Tyrone Toole, Dr Tim Martin, Ranita Sen, Qindong Li and Liam Terris, explains the framework, tools and case studies in detail, and how asset management practitioners can apply these in their day-to-day work.

The emphasis is on reinforcing good practice and its justification and how different preservation and renewal options can be evaluated.

It also provides a detailed introduction into the Pavement Life-cycle Costing tool, followed by worked examples through the presentation of several case studies.

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