ISCA 2020 IMPACTS REPORT FEATURE:
Australia produces about 1.1 million tonnes, equivalent to 5.5 billion bottles, of waste glass per year with only 56 percent of this glass recycled due to issues with recovery rates, sorting, contamination and costs to deliver to one of the few glass recycling plants in Australia1
. As a result, glass waste that is not able to be easily recycled, is either locally stockpiled or landfilled resulting in both environmental and social challenges.
Lismore City Council (LCC) locally recovers and separates waste glass through their collection processes and the “Return & Earn” initiative. The waste glass is stockpiled and then crushed to produce Recycled Crushed Glass (RCG) which is suitable for a range of construction uses such as an alternative to bedding sand and coarse sand substitution within concrete. While its use as bedding sand is now relatively accepted within industry, its application within concrete is less common despite allowances within client specifications.
The use of RCG in concrete is generally not cost competitive against the use of manufactured or natural sand which was identified as a significant barrier to its application. These costs are generally associated with sourcing, transporting, washing, processing and blending the product prior to batching.
Keen to overcome these challenges and demonstrate its viability within the industry, a partnership between Acciona (Lendlease Engineering at the time of the work), Transport for NSW, Pacific Complete and Lismore City Council, with support from NSW Environment Protection Authority funding, enabled a RCG concrete trial to be conducted on the Pacific Highway Woolgoolga to Ballina Section 10 and 11 project. Around 2,000m³ of concrete pavement containing RCG was placed on the project over four individual days of paving. The project’s sustainability initiative diverted 300 tonnes, or over 1.5 million glass bottles, from local landfill and was a first for Acciona and for main line pavement on Pacific Highway projects.
Following on from the success of these trials and supported by Transport for NSW, our team on the Wells Crossing to Glenugie (WC2G) section of the Woolgoolga to Ballina Pacific Highway upgrade project adopted the RCG in concrete initiative with over 12,800m3
of lean mix concrete pavement placed over an eight kilometre section. This equates to 1500 tonnes of crushed glass diverted from landfill (approximately 7.6 million bottles) and the equivalent saving of natural sand resources.
Image: Woolgoolga to Ballina Pacific Highway
The replication of this initiative has assisted with the identification of barriers and practical solutions to the application of RCG within concrete. This insight and lessons learnt will help assess the viability of RCG for future applications and support informed discussions with clients and stakeholders. With further application of this initiative, we believe the demand and efficiency of scale will further drive the cost per tonne down and compete with conventionally sourced materials. We are hopeful that this initiative will start to develop a viable business case for the use of RCG in concrete which could be adopted by clients and contractors more broadly and strengthen the drive towards a circular economy.
Moving forward, we would like to continue to refine the application of RCG within concrete, maximise its use beyond current specifications and share this information with our clients and stakeholders.
The success of this initiative was recognised as the recipient of the 2019 Road Construction Innovation award which is a testament to the collaboration and dedication of Acciona, Transport for NSW, Pacific Complete and Lismore City Council for making this initiative come to fruition.
“As a first for the Pacific Highway, we’re really excited to be working with ACCIONA and Lismore City Council on this initiative to broaden the understanding and application of RCG within concrete and contribute towards our circular economy aspirations.” Transport for NSW
1 National Waste Report 2018 & Waste Stocktake Report 2018
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