Introduction of Warm Mix Asphalt into Western Australia

Warm mix asphalt is a process that allows asphalt to be manufactured, placed and compacted at temperatures lower than conventional hot mix asphalt. The WMA process involves temporarily reducing the bitumen viscosity until the mix is placed. Following a study tour to the USA to better understand and select a suitable technology, it was agreed with MRWA to implement and demonstrate the benefits of warm mix asphalt using the foamed bitumen technique by the injection of water into the bitumen.

This paper discusses the processes followed to rapidly implement the chosen technology into the local asphalt industry and into a project that was under construction. The commercial delivery method is briefly discussed along with the other available technologies. Warm mix asphalt was produced and placed in different layers and configurations within a trial section zone. The details of the trials will be discussed and presented along with some of the challenges and early findings.