The issue
From 2018 to 2021, the Department for Infrastructure and Transport (DIT) delivered the Regency Road to Pym Street (R2P) project, which connects the South Road Superway and Torrens Road to the River Torrens Motorway, and provides a continuous 47 km motorway along the North-South Corridor.
Civil construction infrastructure projects, such as road projects, have significant environmental impacts. Roads involve a large quantity of material use, which generates substantial Greenhouse Gas emissions.
The solution
DIT’s sustainability objectives for the R2P project included minimising whole-of-life emissions and optimising circular economy outcomes. These objectives were embedded in procurement and contract requirements.
The R2P Alliance was appointed by DIT to design and construct various elements required to complete the project, and was tasked with achieving an Infrastructure Sustainability Rating (v2.0) for the design and construction phases.
Resource Efficiency Strategy
In-line with IS Rating requirements, a Resource Efficiency Strategy (RES) was developed during the start of the design phase to assist the project team to identify and assess potential sustainable resource management opportunities that could be achieved during the design, construction and operational phases, and set SMART targets for implementation.
The RES was based on the waste management hierarchy , and included opportunities for reuse of materials, use of recycled materials, and recycling instead of disposal.
The outcome
Some of the sustainable resource management outcomes from the R2P project are outlined below:32,600t of recycled PM2/20 used in the lower layers of the road baseRecycled PM2/20 (road base material with particles ranging from 2 to 20 mm in size) was used as a substitute for virgin quarried material in road base. The material, comprised of recycled crushed concrete, was produced by local recyclers to meet the quality requirements as outlined in DIT’s Master Specification for Supply of Pavement Materials.
170t of 5% recycled glass used in the lower layers of the road base
A trial of 5% recycled glass in PM2/20 was implemented in the lower layers of the road base. It was the first time that recycled glass was used as a substitute for natural sand in the lower layers of road base in South Australia.
Use of recycled glass aggregate in road base, as well as asphalt, is now permitted in DIT’s Master Specification.
Recycled materials in asphalt (soft plastics, printer cartridges, RAP, canola oil)
ReconophaltTM, an asphalt product that uses soft plastics as a partial binder replacement in asphalt, was used in a trial on the R2P Project.
ReconophaltTM was also used in the construction of the site office car park, and in shared user paths.
The use of ReconophaltTM diverted a large amount of waste from landfill, including:
- 409 tonnes of Recycled Ashphalt Plannings
- 794 kg of recycled canola oil
- 19,230 waste toner cartridges
- 798,105 plastic bags.
133 tons of aggregate diverted from landfill
Through assessment, the use of 30% recycled aggregate content in kerbs was found meet the design and technical specification requirements for the project.
80 m of noise walls re-used
An approximate 80 m of noise wall panels that had been identified for demolition were instead re-used on an adjacent location, and diverted from landfill.
What’s next?
The R2P Alliance has demonstrated that it is possible to improve the circular economy outcomes in civil infrastructure projects through the identification and implementation of circular economy initiatives.
The main drivers behind the success of this project were consideration of sustainable solutions in the design stage, and use of contractual requirements.
DIT’s Master Specification parts ‘Sustainability in Design’ and ‘Sustainability in Construction’ now include several mandatory sustainability initiatives (including use of recycled materials) which contractors are required to investigate and implement if viable.
The initiatives considered as part of the R2P Project were used to create a checklist, which can be utilised by future civil infrastructure projects as a prompt for potential improved circular economy outcomes.
Banner image: Installation of ReconophaltTM (courtesy of the Department for Infrastructure and Transport)
