Unbound granular materials play a crucial role in providing cost-effective road transport infrastructure across Australia and New Zealand. Compared to the thick asphalt and concrete pavements common in urban centres, thin bituminous surfaced unbound granular pavements offer a more economical solution for sealed road networks, albeit with lower load-bearing capacity and in some cases lower performance reliability.

The performance of unbound granular materials is primarily influenced by their shear strength, modulus, and resistance to material breakdown under construction and traffic loads. Improved performance tests are required to provide practical pavement design methods and performance-based specifications for their use in construction.

This webinar presents research to identify new performance tests recommended for future Austroads research. Performance characterisation methods were reviewed, including repeated load triaxial (RLT) testing and wheel tracker testing. In identifying potential new improved laboratory test methods, particularly in relation to rut-resistance, cognisance was taken of the shear stress reversals due to rolling wheel loads that occur in service.