RMIT University has developed a new building material composed entirely of cardboard, water and soil, making it reusable and recyclable.
Dubbed ‘cardboard-confined rammed earth’, the material can be produced with about one quarter of concrete’s carbon footprint, while reducing waste going to landfill.
Cement and concrete production account for about 8 per cent of annual global emissions, while more than more than 2.2 million tonnes of cardboard and paper are sent to Australian landfill sites each year, according to RMIT University.
Lead author Jiaming Ma from RMIT says the development of the product marks a significant advancement toward a more sustainable construction industry.
“Modern rammed earth construction compacts soil with added cement for strength,” he said.
“Cement use is excessive given the natural thickness of rammed earth walls. But cardboard-confined rammed earth, developed at RMIT University, eliminates the need for cement and boasts one quarter of the carbon footprint at under one third of the cost, compared to concrete.
“By simply using cardboard, soil and water, we can make walls robust enough to support low-rise buildings. This innovation could revolutionise building design and construction, using locally sourced materials that are easier to recycle.
“It also reflects the global revival of earth-based construction fuelled by net zero goals and interest in local sustainable materials.”
Another benefit of cardboard-confined rammed earth is that it can be made on the construction site, 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,” study corresponding author Yi Min Xie said.
“This would significantly cut transport costs, simplify logistics and reduce upfront material demands.”
Ma said cardboard-confined rammed earth could be an effective solution for construction in remote areas, such as regional Australia, where red soils – ideal for rammed earth construction – are plentiful.
