This article is authored by Dr Nariman Saeed | School of Computing, Mathematics and Engineering
The construction sector, while critical to infrastructure and economic development, is among the most environmentally intensive industries in Australia. This is especially concerning in regional communities, where the need for new infrastructure and the environmental impacts are particularly pronounced. The Sustainability in Engineering research group the research wing of CSU Engineering, is committed to delivering sustainable engineering solutions tailored to the needs of regional Australia. Our research initiative, titled “Waste to Worth” focuses on upcycling industrial waste into green construction materials, with an emphasis on reducing the use of virgin resources, diverting the wastes from landfill and incorporating waste into construction applications through scientifically validated recycling approaches.
The scale of industrial and municipal waste in Australia is staggering, with many of the largest contributors located in regional areas:
- 620 million tonnes of mine tailings were generated during 2020–2021, largely from mining operations based in rural and remote regions.
- 67 million waste tyres were discarded in 2023–2024.
- 1.36 million tonnes of waste glass were recorded in 2022–2023.
At the same time, Australia consumed 10 million tonnes of cement in 2020–2021, contributing to 4.7 million tonnes of CO₂ emissions
At the Sustainability in Engineering research group, we adopt two primary circular economy principles in our Waste to Worth initiative:
- Reduce: We aim to minimise the use of natural virgin resources in construction—particularly in cement and concrete —by replacing them with upcycled industrial waste.
- Recycle: We develop practical and scientifically tested pathways to recycle waste materials into durable, cost-effective, and high-performance green concretes.
Our strength lies in material conversion—transforming underutilised or landfilled waste into value-added construction inputs. In collaboration with Western Sydney University and Central Queensland University, our team has conducted several experimental investigations into industrial waste utilisation in concrete, each aimed at achieving real reductions in both environmental impact and material costs.
Below are the major materials we have studied and validated for use in construction:
Coal Tailings – Cement Production and Cement Replacement
We have tested coal tailings as a raw material for cement production, helping to reduce the dependency on virgin limestone and clay. This has also shown potential of 29% reduction in fuel consumption. In addition, we have successfully used coal tailings as a partial cement replacement, demonstrating a reduction of minimum 20% of cement usage in laboratory-scale concrete mixes.
Copper Tailings – As Cement and Sand Substitute
In partnership with a mining in regional NSW, we have developed concrete mixes using copper tailings as both: a partial cement replacement (10%), and a fine aggregate replacement (up to 50%). These mixes not only meet strength requirements but also address two problems: the environmental burden of tailings storage and the scarcity of natural sand in many inland regions.
Sugarcane Bagasse Ash (SCBA)
A by-product of sugar mills common in regional NSW/Queensland, SCBA has been incorporated into our cement replacement trials. Lab scale results indicate that it enhances concrete sustainability by 20% reduction in cement usage, while contributing positively to compressive strength when optimally blended with cement.
Waste Recycled Glass– Binder and Aggregate Replacement
Waste glass, which totals over 1.3 million tonnes annually, is often not recycled due to contamination or colour mismatch. We used crushed glass and glass powder as partial aggregate and cement replacement in concrete, effectively improving durability and lowering the demand for virgin quarry materials.
Waste Tyres – Sand Replacement
Through shredding and granulation, waste tyres are converted into rubber crumb and used as partial sand replacements in concrete applications. This application not only reduces environmental pressure from tyre stockpiles but also improves the flexibility and impact resistance of the final product. In an ongoing PhD research project, we are investigating innovative eco-friendly rubber crumb treatment methods to improve comprehensive strength of the manufactured rubberised concrete.
All waste-integrated concrete mixes undergo rigorous testing to ensure compliance with engineering standards. Some of the key outcomes include:
Concrete containing coal tailings and SCBA achieved almost of control compressive strength after 28 days. The glass powder-based binder was produced at 33% lower cost than traditional cement (OPC), making it economically attractive. Even more impressively, the optimised mix resulted in a 53% reduction in greenhouse gas emissions, offering a significant step toward decarbonising the construction industry. Tyre-based concretes exhibited improved impact energy absorption, ideal for use in regional footpaths or buffer zones. These material innovations support the broader goal of carbon emission reduction, resource conservation, and regional material security.
Our research has been guided by the belief that regional communities should have access to low-carbon, affordable, and locally sourced construction materials as well as having their local land cleared
Our next steps include:
- Scaling up through pilot applications of our waste-based concrete in regional construction projects, such as footpaths, pavements, and community infrastructure.
- Engaging local councils and regional contractors in co-designing trials and training programs.
- Seeking industry and government funding to establish mini waste-processing units that can serve remote sites using locally available waste.
Our Research Group is proud to lead the “Waste to Worth” initiative—pioneering practical, science-based solutions to upcycle industrial waste into green building materials tailored to regional Australia. In doing so, we are not only aiming at reducing landfill and cutting carbon emissions, but also supporting regional self-reliance, lowering construction costs, and contributing to a more resilient and circular built environment. We will continue to partner with regional stakeholders to bring these solutions to scale, educating communities and ensuring a sustainable construction future for the communities that need it most.