Hot Mix Asphalt (HMA) has been the world’s main type of paving material. In the last 10 to 15 years
the asphalt industry has recognised the importance of sustainability and the need for new
innovative materials. The introduction of warm mix asphalt (WMA) technologies allow asphalt
production and compaction temperatures to be reduced. However the issue of their longer term
durability has been unknown. This investigation considered the development of a new approach to
predicting the durability of WMA based on simulated trafficking and 3D modelling. Roller compacted
SMA14 test specimens were prepared using 4 WMA additives and compared with a WMA control
containing no additive and a conventional HMA. The test specimens were subjected to simulated
accelerated trafficking using modified Wessex immersion wheel track test equipment. This had been fitted with a pneumatic tyre and modified so the tyre is dragged across the test specimen in one direction. This causes the surface to eventually ravel and breakup. 3D models of the test specimen before and after simulated trafficking were made using a hand held ZScanner 800 3D laser. Changes in the 3D models were analysed using DigitalSurf MountainsMap6 Premium software. In developing this test method it was found that test temperature and compaction were important factors in causing the asphalt mix surface to ravel. After testing at 300 C it was concluded that addition of the 4 additives used did not detrimentally affect the durability of WMA SMA14 asphalt mixes in comparison to the HMA control. Based on the findings of this test method it is concluded that if properly compacted, the use of additives will result in warm mix SMA that is comparable to hot mix SMA in terms of aspects of durability assessed.
