Pavement

This report describes a literature review on the bitumen/binder specifications and test methods used in Australasia, USA, Europe and South Africa. The project investigated whether the Australian and New Zealand bitumen specifications are adequately related to performance, and appropriate for evaluating the current generation of bitumens.

The Australian bitumen specification (AS 2008) and PMB specification (AGPT/T190) were found to be able to rank the performance of binders at high road temperatures (e.g. 60 °C), and also could account for regional climatic variations. Concerns have been raised in New Zealand about the New Zealand bitumen specification (NZTA M1) as bitumens are increasingly being imported into the country. As a result of these concerns, new bitumen/binder specifications have been under development in New Zealand. Preliminary New Zealand validation studies appear to suggest that the new specifications may be appropriate for evaluating the performance of asphalt and sprayed sealing grade binders in New Zealand.

The current Australian and the proposed New Zealand bitumen specifications were not immediately interchangeable in their current forms, and thus further studies would be required if a common specification is to be developed for the two countries in the future.

A review of international development work into performance-based specifications indicated that traditional binder tests (e.g. viscosity at 60 °C and penetration at 25 °C) were generally considered suitable for ranking the performance of bitumens. A number of potential performance-based tests are currently under development in various countries to characterise the properties of PMBs. The results of this research are expected to provide useful information when the Australian and New Zealand PMB specifications are updated.