RMIT University engineers have developed a new reusable and recyclable construction building material called cardboard-confined rammed earth.
It reportedly has only a quarter of concrete’s carbon footprint, a crucial win for sustainability, given that cement and concrete production make up about eight percent of annual global emissions.
If the new building material is found to be commercially viable, it could play a significant part in helping divert some of the approximately 2.2 million tons of cardboard and paper that are sent to landfills each year.
Cardboard has previously been used in the construction of temporary structures and disaster shelters, such as Shigeru Ban’s iconic Cardboard Cathedral in Christchurch.
Using this as the starting point, the RMIT University team considered combining rammed earth with cardboard for added durability.
“Modern rammed earth construction compacts soil with added cement for strength. Cement use is excessive given the natural thickness of rammed earth walls,” RMIT lead author Dr Jiaming Ma says.
“By simply using cardboard, soil and water, we can make walls robust enough to support low-rise buildings.”
The researchers note that the cardboard-confined rammed earth can be made on the construction site itself by compacting the soil and water mixture inside the cardboard formwork, either manually or with machines.
“Instead of hauling in tonnes of bricks, steel and concrete, builders would only need to bring lightweight cardboard, as nearly all material can be obtained on site,” Emeritus Professor Yi Min ‘Mike’ Xie says.
“This would significantly cut transport costs, simplify logistics and reduce upfront material demands.”
The team indicates the new material could be an effective solution for construction in remote areas where red soils, which are best suited for rammed earth construction, are found.
“Rammed earth buildings are ideal in hot climates because their high thermal mass naturally regulates indoor temperatures and humidity, reducing the need for mechanical cooling and cutting carbon emissions,” Xie says.
The mechanical strength of the material varies based on the thickness of the cardboard tubes.
The discovery of this new product comes as Australia’s government has set a national target to reduce emissions by 62–70 percent below 2005 levels by 2035.
The government has indicated that one of the focus areas to reduce emissions will be the built environment.
Read more: FM sector responds to government’s latest emissions targets
