Erik Denneman, Director – Technology and Leadership at the Australian Asphalt Pavement Association, looks at the benefits of using reclaimed asphalt pavement and the push behind its uptake in Australia.
One of the advantages of asphalt pavements over other road construction materials is the relative ease of recycling. Reclaimed asphalt pavement (RAP) can be fully reused in new asphalt product, simply by crushing and screening it, and reintroducing it to the asphalt production process.
The value of the precious constructions materials in RAP (mineral aggregate and bitumen) is maximised by reusing it in asphalt pavements as it reduces the need for new raw materials.
Reuse of RAP in new mixes should therefore be promoted over other forms of recycling (or down cycling) such as use of RAP as granular subbase or back fill. Australian Asphalt Pavement Association (AAPA) members strongly support the principles of reuse both from a sustainability and a cost efficiency perspective.
Austroads recently completed a study aimed at maximising the reuse of RAP. The outcomes of the project include procedures for the characterisation of RAP material engineering properties. These procedures are in line with international best practice and will enable higher proportions of RAP to be used in Australian asphalt pavements.
There is a widely held perception that material properties in RAP stockpiles are highly variable and that using RAP, especially at high proportions, will negatively affect consistency of the asphalt product. This perception is unfounded. Published research shows that, if RAP stockpiles are properly managed, the grading of the aggregate in the RAP will be at least as consistent as that of virgin sources, binder content and binder properties of the RAP can be expected to be uniform as well.
In June 2018, AAPA published its Reclaimed Asphalt Pavement (RAP) Management Plan. This document sets a standard practice for the control of quality and consistency in the winning of RAP and the delivery of the processed RAP for the reuse in asphalt pavements.