Austroads Updates Guide to Pavement Tech for Asphalt & Binders
BY AsphaltPro Staff
Updates to Austroads’ guides on asphalt and stabilizing binders advance pavement practices
Austroads has released updated editions of two key resources in its Guide to Pavement Technology, providing fresh direction for practitioners working with asphalt and stabilizing binders. These revisions reflect current industry practice, evolving standards, and sustainability priorities in the region, ensuring that road agencies, designers, engineers, and material suppliers have access to consistent and practical guidance.
By enabling in situ recycling of existing pavement layers, stabilization reduces reliance on non-renewable resources and lowers carbon emissions.
Part 4B: Asphalt
The updated Guide to Pavement Technology Part 4B: Asphalt delivers comprehensive advice on the selection, classification, specification, and evaluation of source rock and aggregates for pavement construction. Recognizing that rock durability underpins long-term road performance, the guide examines the geological and engineering factors that influence crushed rock quality. It also addresses the mechanisms that contribute to material distress once in service.
Incorporating igneous, sedimentary, metamorphic, and recycled materials—including industrial slags—Part 4B underscores the need to align durability assessment with contemporary testing and quality assurance practices. The document acknowledges variations in local geology, testing protocols, and agency requirements across Australasia, while aiming to standardize expectations wherever possible. By integrating advances in durability evaluation and referencing national standards, Part 4B serves as a vital tool for agencies and operators seeking to optimise resource use and extend pavement life.
Part 4L: Stabilizing Binders
Meanwhile, the revised Guide to Pavement Technology Part 4L: Stabilising Binders focuses on the role of chemical and mechanical additives in enhancing pavement performance. Stabilization, achieved through binders such as lime, cement, pozzolans, bitumen and polymers, modifies the inherent properties of pavement materials to better withstand operational, geological and climatic conditions.
Beyond engineering benefits, stabilization also contributes to sustainability objectives. By enabling in situ recycling of existing pavement layers, stabilization reduces reliance on non-renewable resources and lowers carbon emissions. Part 4L outlines binder types, in situ and plant-mixed construction practices, and points practitioners to related Austroads volumes for detailed material selection and structural design guidance, notably Part 4D, Part 2, and Part 5.
How We Can Incorporate Recycled Plastics in Asphalt Pavement
Supporting Consistent, Sustainable Practice
Together, the updates to Parts 4B and 4L of the Guide to Pavement Technology highlight Austroads’ commitment to harmonizing practice across jurisdictions while accommodating local conditions. With clearer direction on both aggregate performance and binder application, these resources support the delivery of durable, sustainable and cost-effective pavements across Australia and New Zealand.
In addition to the updates to Parts 4B and 4L of the guide, Austroads has recently released new technical specifications. Two of them tie directly to the information discussed above.
Austroads Technical Specification ATS 3340 for plant mix pavement stabilization using foamed bitumen sets out the requirements for the construction of a stabilized pavement using foamed bitumen and secondary stabilizing binders that have been mixed in a stationary pugmill. Then Austroads Technical Specification ATS 3350 for in situ pavement stabilization using foamed bitumen sets out the requirements for in the in situ stabilization of pavement material using foamed bitumen and secondary stabilizing binders.