Since 2020, when the Australian Government passed legislation prohibiting the export of waste (DCCEEW 2024), industry and governments have been challenged to provide value-adding alternatives to landfill (DCCEEW 2025). Australia’s transport agencies recognised the capacity of the country’s expansive transport infrastructure to absorb significant quantities of this waste (Hall et al. 2022).
Since 2020, when the Australian Government passed legislation prohibiting the export of waste (DCCEEW 2024), industry and governments have been challenged to provide value-adding alternatives to landfill (DCCEEW 2025). Australia’s transport agencies recognised the capacity of the country’s expansive transport infrastructure to absorb significant quantities of this waste (Hall et al. 2022).
Furthermore, the scarcity of natural resources has sparked not only the development of innovative substitutes by researchers and industry, such as bio-based alternatives to bituminous binders (Pandelidi et al. 2025), but also a need to understand how to effectively incorporate marginal and non-standard materials (Austroads 2018).
Australia has also committed to decrease greenhouse gas emissions progressively, with a goal to achieve net zero by 2050. The transport sector, however, is increasingly projected to be Australia’s largest emitter by 2030 (DITRDCA n.d.). Product stage emissions for standard infrastructure materials alone account for an estimated 5% of Australia’s total greenhouse gas emissions and their transportation an additional 0.3% (Infrastructure Australia 2024). Figures specific to sourcing and transporting materials for road construction are not readily available. However, it is recognised that increased uptake of locally available materials will decrease overall project costs and improve sustainability outcomes (Austroads 2018).
There is, therefore, an opportunity for innovation where pathways to decrease transportation distances and resource requirements need to be identified. Efforts so far, though, have shown that the solution to these sustainability challenges is not straightforward. In this context, there are two inherent situations that need to be overcome. Firstly, new materials, whether they are recycled, innovative, marginal or non-standard, introduce an element of the unknown and often require additional assessment for engineering performance, supply chain sustainability, re-recyclability, environmental impacts, and occupational health and safety (OHS) implications (Zhalehjoo et al. 2025). Secondly, the lack of harmonisation of test methods (Austroads 2023) and the broad adoption of partially prescriptive specifications across Australia form a barrier to the swift adoption of alternative materials. To enable innovation, test methods and specifications need to be materials-agnostic and outcome-based.
As a first step, a materials assessment framework was developed to provide a structure for the comprehensive and efficient assessment of new materials and to enable their successful adoption in road infrastructure.
The framework was designed to be appropriate for the assessment of recycled, marginal, non-standard and innovative materials, and considers market capacity, potential environmental impacts, potential OHS impacts and engineering performance.
The framework introduces two consecutive levels of assessment. Level 1 seeks to understand available volumes and location and assess any relevant environmental and OHS impacts. The outputs of this assessment include:
A hold point follows Level 1 assessment, during which the decision is made on whether the material is safe, sustainable and economically viable. Level 2 outlines the pathway to assessing relevant engineering performance and re-recyclability. During Level 2 assessment, the material and/or mix is tested as/if required to produce an initial comprehensive list of potential applications. This list is then progressively reduced, based on findings from Level 1 assessment.
The evaluation and adoption of recycled, innovative, marginal and non-standard materials in road infrastructure, is not new in Australia. However, it has not been systematic, predominantly focusing on the execution of an expensive laboratory and implementation program, excluding potentially detrimental aspects from the assessment. There has also been a lack of subsequent monitoring and reporting of field evaluation trials, which means that new learnings are not gained, so effort is duplicated.
The developed framework has considered all relevant factors and proposes an efficient and robust pathway to assess new materials minimising effort, redundancies and duplications.
It is recommended that the assessment framework is further developed into an online platform, where the user can provide three inputs (namely, material type, available quantity and state or territory) and is given an optimum assessment program. The user may be called to progressively select from a list of potential applications generated after all controls have been applied. To develop this online platform, a database needs to be built in the background, including:
Importantly, although the developed framework can be adopted with existing test methods and standards in place, it is recognised that unless performance-based specifications are developed, its impact will inevitably become limited. The development of appropriate test methods and reliable performance-based specifications will require:
Lastly, Pandelidi and Grenfell (2024) identified that methods suitable for the environmental and OHS implications of new materials are yet to be developed, with available tests being unsuitable for roading materials.
