Reviewed by Frances BriggsSep 22 2025
Turning cardboard waste into a cement-free building material, RMIT researchers introduce cardboard-confined rammed earth, cutting landfill, lowering emissions, and providing a low-cost alternative for sustainable construction.
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Published in Composite Structures, the material is made from waste cardboard, soil, and water, and could be a substitute for one of the world's most carbon-intensive building materials: concrete. It can be made manually or with machinery, making it flexible for varying locational contexts.
Not only is it sustainable as an alternative for concrete, but as it could make use of waste cardboard. In Australia, over 2.2 million tons of cardboard and paper are sent to landfill each year, while cement and concrete production contribute approximately 8% of global annual emissions.
Lead author Dr. Jiaming Ma from RMIT stated that the development of cardboard-confined rammed earth represents a significant step toward a more sustainable construction industry.
Modern rammed earth construction compacts soil with added cement for strength. Cement use is excessive given the natural thickness of rammed earth walls. By simply using cardboard, soil, and water, we can make walls robust enough to support low-rise buildings.
Dr. Jiaming Ma, Lead Author, RMIT
Developed at RMIT University, cardboard-confined rammed earth is a highly sustainable and cost-effective alternative to concrete. By eliminating the need for cement, the material boasts a carbon footprint of just one-fourth the size of concrete and costs less than one-third as much.
This innovation could revolutionize building design and construction, using locally sourced materials that are easier to recycle. It also reflects the global revival of earth-based construction fueled by net zero goals and interest in local sustainable materials.
Dr. Jiaming Ma, Lead Author, RMIT
According to the corresponding author, Emeritus Professor Yi Min 'Mike' Xie, this innovative advancement could lead the way to a leaner and more sustainable approach to construction.
Instead of hauling in tons of bricks, steel, and concrete, builders would only need to bring lightweight cardboard, as nearly all material can be obtained on site.This would significantly cut transport costs, simplify logistics, and reduce upfront material demands.
Yi Min 'Mike' Xie, Study Corresponding Author and Emeritus Professor, RMIT
Dr. Ma stated that cardboard-confined rammed earth could be an ideal construction solution for remote areas, such as regional Australia, where the abundant red soils are perfect for rammed earth building, as their high thermal mass naturally regulates indoor temperatures and humidity.
The mechanical strength of the cardboard-confined rammed earth depends on the thickness of the cardboard tubes. To account for this, the researchers developed a formula that allows builders to calculate strength based on cardboard thickness, ensuring reliable performance.
This gives us a practical tool for designing with confidence.
Dr. Jiaming Ma, Lead Author, RMIT
In a separate study led by Ma, carbon fiber was combined with rammed earth, demonstrating strength comparable to that of high-performance concrete.
References
Ma, J., et al. (2025) Cardboard-confined rammed earth towards sustainable construction. Structures. doi.org/10.1016/j.istruc.2025.110117.
Ma, J., et al. (2025) CFRP-confined rammed earth towards high-performance earth construction. Composite Structures. doi.org/10.1016/j.compstruct.2025.119512.