Decisions that are made with a focus on sustainability can also lead to economic and cost advantages. The substitution of materials used on Gateway WA was another way the project team derived sustainable benefits for the project. The project team looked at materials used for road construction to see if sustainable benefits could arise from the replacement of one material for another.
In road construction higher modulus equals greater strength, which in turn means a thinner deep lift asphalt pavement that achieves the same design life of 40 years. The changing of asphalt binder from the traditional Class 320 bitumen to Class 600 was adopted by the project and this enabled a higher modulus asphalt to be obtained.
The result of this was an approximate 10 percent reduction in total asphalt quantity for the project overall. Not only was this a significant cost saving for Gateway WA but it also reduced greenhouse gas emissions so derived both economic and environmental benefits.