The Morley-Ellenbrook Line Project is focused on working more sustainably to reduce carbon impacts of materials by more than 15 per cent, improve resource efficiency and support a circular economy by using recycled materials. A number of initiatives have been implemented to help reach these sustainability targets.
FOGO trial
The project has committed to using 20 per cent Food Organics and Garden Organics (FOGO) in imported topsoil used for landscaping. FOGO is made from household food scraps and garden waste, collected by councils and taken to waste facilities for processing to Australian Standards.
As FOGO compost soil is not typically used for native plants (and natives are used in project landscaping), the trial was introduced in a small, landscaped area near Whiteman Park Station and will run for multiple seasons with different compositions of FOGO/soil conditioner blends monitored across sample native plants.
The root growth of the plants will be carefully recorded, enabling teams to compare all plant and soil compositions, address any concerns, and ultimately identifying the most suitable one for long-term sustainability and project durability.
A collaboration between landscaping contractors, regional councils, recovery facilities and soil scientists, the trial is expected to set a precedent that supports the use of FOGO and gives teams confidence to embrace this and other new materials, while encouraging innovative landscape practices.
The FOGO trial area adjacent to Whiteman Park Station. The FOGO trial area at Whiteman Park Station.
Crushed recycled concrete trial
Crushed recycled concrete (CRC) is being trailed for the base asphalt layer in Ballajura and Noranda station car parks. CRC is made of concrete debris from construction and demolition projects and is usually reused for driveways, pathways, garden beds and more.
When any concrete structure, road, footpath or car park is demolished, the materials are typically deposited into landfill, and as concrete isn’t biodegradable it doesn’t decompose. At the same time, new concrete is created and the process begins all over again.
The use of CRC aims to reduce materials going to landfill and result in reduced carbon emissions – it’s estimated that around 0.7t of CO2e is saved by substituting around 16,000t of virgin crushed rock used as basecourse with CRC.
The ongoing trial will be monitored and will facilitate the wider uptake of this recycled/reused material in applications that have typically been considered higher risk.
Portland cement reduction
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar and other materials. It’s use is responsible for over 8 per cent of global carbon emissions, and is one of the project’s most carbon intensive materials.
The project has therefore set a target to replace a minimum of 30 per cent Portland cement on poured concrete mixes used. To date, teams are exceeding this, achieving an average of 53 per cent replacement rate by using recycled content instead (known as supplementary cementitious materials or SCMs).
SCMs are a waste by-product of steel making and energy production and reduce the embodied carbon of concrete while providing technical benefits such as durability, increased strength and reduced early heat. To date, the project has replaced around 11,571t of Portland cement with SCMs, helping exceed Green Star targets by more than 20 per cent.
Cement works onsite
Hollow core noise walls
The amount of traditional concrete used on site is also being reduced through a hollow core noise wall system that contains 30 per cent less embodied carbon than standard noise wall panels.
Around 770 hollow core panels have been installed from Gnangara to Ellenbrook, with other benefits of the sustainable product including:
- 50 per cent reduction on transport and associated emissions due to reduced weight
- reduced installation time compared to standard noise walls, resulting in a reduction of other environmental impacts such as construction noise, vibration and air quality
- less defects and less wastage with the hollow core process compared to standard noise wall panels.
Hollow core noise walls pre-installation. Completed hollow core noise walls.
Project sustainability achievements to date
- 269 tonnes of recycled asphalt pavement used across the project
- 16,438t of crushed recycled concrete used as basecourse at Ballajura and Noranda car parks – just over the target of 15,000t.
- 11,571t of Portland cement (a high embodied carbon material) replaced with recycled content