Austroads has published new testing frameworks that measure the potential environmental impacts of road materials designed with recycled plastic waste.
“This report is the third of a series of reports for a pioneering project initiated by Austroads and led by RMIT University in response to a growing interest in the use of waste materials in road infrastructure,” said Ross Guppy, Austroads Transport Infrastructure Program Manager.
“The frameworks provide innovative performance and environmental assessment procedures to test incorporating recycled plastic into bitumen as a polymer modifier and the addition of high melting point recycled plastics into asphalt as an aggregate replacement.”
Performance characteristics of the recycled plastic modified bitumen (RPMB) outlined in the report will allow the properties of asphalt to be analysed and its benefits quantified to ensure the mix is equal to or better than available conventional mixes.
The report provides a laboratory testing framework to assess bitumen and asphalt emissions. “Onsite testing of emissions is practical, but there are too many variables. Our laboratory test approach allows for the variables to be controlled for exact comparisons between the different testing parameters,” said Ross.
Additionally, the report offers a methodology to assess the release of microplastics (MPs) from plastic-modified asphalt and details the impact of the plastic source, content and incorporation method in asphalt on MPs release.
“If the performance of asphalt containing recycled plastics is comparable to the performance of the bitumen or modified binder intended to be substituted, the use of plastic in bitumen may represent a feasible alternative to virgin material,” said Ross.
The report includes a testing pathway to assess both the performance and environmental impacts, in terms of microplastics and emissions, of any plastic-modified asphalt regardless of the type and content of plastics used in the mix.
The project also investigated the possibility of recycling reclaimed plastic-modified asphalt pavements (P-RAP) at the end of their service life.
“The underlying principle of our investigation was to ensure that the P-RAP material can be used in a similar manner as conventional reclaimed asphalt pavement (RAP) material without drastically modifying the asphalt plant processes or reducing the performance of the new asphalt mix with P-RAP.”
Part B of the report will provide the details of performance test results of asphalt mixes produced with RAP and P-RAP.
To download the Part A report, click here.
Austroads’ previous two reports are available for download here: