Pavement

This report details the testing of 21 Austroads jurisdictions mixes and one airport mix to develop a relationship between the Austroads Gyropac Gyratory compactor, which is now redundant, and the Servopac (setup to AS/NZS) and Superpave Gyratory Compactors. The review of the testing data found that while the relationship between the different gyratory compactors was somewhat affected by mix properties, especially at refusal void levels, mix properties have little impact on the critical mix design parameters of density and air voids. The testing found that equivalent densities can be achieved at constant cycles for each gyratory compactor, allowing for relatively easy adoption of different compaction methods in specifications.

While the testing found a constant offset, a review of available test data found that most Austroads jurisdictions design to compaction levels above the current Austroads levels, with New Zealand designing to the much higher Superpave compaction levels. As a result, a direct offset to the current Austroads compaction levels was not recommended.

Based on testing the range of mixes, initial compaction levels for the three Austroads traffic levels using the Superpave Gyratory Compactor have been recommended.

Before full adoption, there is a need for each Austroads jurisdiction to validate these limits for their locally manufactured asphalt mixes.

Watch a webinar about the report with Bevan Sullivan and Sean Dorahy.