Could discarded cardboard become the future of sustainable construction? Researchers at RMIT think so, with a breakthrough that fuses waste and earth into strong, reusable walls.
RMIT University researchers have developed a low-cost, low-carbon building material that blends cardboard, soil and water. Called cardboard-confined rammed earth, the system reduces the carbon footprint of construction by about 75% compared to concrete, while being reusable and recyclable.
The process repurposes discarded cardboard – of which 2.2 million tonnes end up in Australian landfill each year – into formwork tubes that contain compacted soil. By removing cement from the mix, the material avoids one of the most emissions-intensive ingredients in construction, while still creating walls robust enough for low-rise buildings.
Concrete accounts for around 8% of global carbon emissions, and cement is the main culprit. By swapping it out, this RMIT innovation makes earth-based construction more viable at scale. It also keeps cardboard in circulation rather than landfill.
Dr Jiaming Ma, who led the research, says the approach taps into a growing global revival of earth-based construction. “By simply using cardboard, soil and water, we can make walls robust enough to support low-rise buildings,” he explains. “This innovation could revolutionise building design and construction, using locally sourced materials that are easier to recycle.”
Practical Advantages
The system can be made on-site with soil and water compacted inside the cardboard tubes, either manually or by machine. That means fewer trucks delivering heavy bricks, steel or concrete – just rolls of lightweight cardboard.
According to Emeritus Professor Yi Min ‘Mike’ Xie, the result is a “leaner, greener” construction method. Builders save on transport, simplify logistics and reduce upfront material demand. In regional areas with abundant red soils, the method could provide an especially practical solution.
There’s also a performance edge. Rammed earth walls naturally regulate temperature and humidity, making them well suited to hot climates. By adjusting the thickness of the cardboard tubes, the strength of the walls can be tuned, opening the door to more flexible applications.
Future Development
Beyond the current prototype, Ma and his team have also experimented with carbon fibre reinforcement, finding results comparable to high-performance concrete. They are now seeking industry partners to develop the material further, from field trials to commercialisation.
As the construction continues to address the urgent need to decarbonise, innovations like cardboard-confined rammed earth hint at a future where buildings draw on local soils and recycled materials instead of carbon-heavy imports.
Sources
‘Cardboard-confined rammed earth towards sustainable construction’, with RMIT co-authors Jiaming Ma, Hongru Zhang, Vahid Shobeiri, Ngoc San Ha, Srikanth Venkatesan, Dilan Robert and Yi Min ‘Mike’ Xie, is published in Structures. (DOI: 10.1016/j.istruc.2025.110117)
‘CFRP-confined rammed earth towards high-performance earth construction’ is published in Composite Structures. (DOI: 10.1016/j.compstruct.2025.
