A team of engineers in Australia has developed a groundbreaking building material that uses just cardboard, soil and water to create walls strong enough for low-rise buildings while carrying only a quarter of the carbon footprint of traditional concrete.
Dubbed cardboard-confined rammed earth, the innovation also offers a solution to the millions of tons of cardboard and paper sent to landfill each year in Australia.
Inspired by iconic designs such as Shigeru Ban’s Cardboard Cathedral in New Zealand, the RMIT University team has combined the durability of rammed earth with the versatility of cardboard.
Unlike conventional rammed earth, which relies heavily on cement for strength, this new material eliminates cement entirely, making it cheaper, more sustainable and fully recyclable.
Lead author Dr Jiaming Ma says the material represents a major step toward greener construction.
“By simply using cardboard, soil and water, we can make walls robust enough to support low-rise buildings,” he says.
“This approach could transform building design, using materials that are locally sourced and easier to recycle, while supporting global net zero goals.”
Emeritus Professor Yi Min ‘Mike’ Xie highlights the practical benefits for construction logistics: “Instead of hauling tonnes of bricks, steel and concrete, builders would only need lightweight cardboard and soil, cutting transport costs, simplifying logistics, and reducing upfront material demands.”
The material can even be produced on-site, compacting the soil-and-water mixture inside cardboard formwork, either manually or with machines. Its thermal mass naturally regulates indoor temperatures, making it ideal for hot climates and reducing reliance on mechanical cooling.
The strength of the cardboard-confined rammed earth depends on the thickness of the cardboard tubes, and the team has developed a formula to measure this precisely. In a related study, Jiaming also combined rammed earth with carbon fibre, producing a material comparable in strength to high-performance concrete.
With sustainability, cost efficiency and practical performance, cardboard-confined rammed earth could mark the start of a greener era in construction, one wall at a time.
