Improvements in full depth asphalt pavement specifications and construction practices in Western Australia

Close to $2 billion dollars of major road construction in Western Australia over the last seven years has led to significant advances in the design manufacture and construction of full depth asphalt pavements. As each project progressed, opportunities were identified for improvements. After the fact investigations, lessons learnt, investment in overseas studies and literature reviews indicated that further improvements were required. Investigations into the performance of previous projects identified the presence of water in the pavement structure despite considerable effort to build them in the dry. The introduction of a new class of bitumen to Western Australia, and significant changes in specifications and construction practices led to a marked improvement in the quality of the finished product and an $8.0 million dollar cost saving in asphalt on a single project. Delivery contracts that are conducive to collaboration between the Client, Designer, Contractor, Subcontractor and Supplier was a key element in order to achieve to the outcomes that were achieved in a relatively short period of time This paper describes the experiences and processes that were followed that led to the Gateway WA project being a ground breaking innovative project in terms of asphalt technology in Western Australia.