Australian engineers have created a surprising new building material that could dramatically cut the environmental cost of construction.
By combining cardboard, soil, and water, they have developed a strong, low-carbon alternative to concrete called cardboard-confined rammed earth.
Concrete is the most widely used building material in the world, but it comes with a heavy environmental price.
Producing cement and concrete is responsible for about 8% of global carbon emissions.
At the same time, millions of tons of cardboard end up in landfills every year. In Australia alone, more than 2.2 million tons of cardboard and paper waste are dumped annually.
Researchers at RMIT University saw an opportunity to solve both problems at once.
They built on the centuries-old technique of rammed earth, in which soil is compacted to form walls, but instead of mixing in cement for strength, they used recycled cardboard tubes as the supporting framework.
The result is a reusable, recyclable material that has just one quarter of concrete’s carbon footprint and costs less than a third to make.
Lead researcher Dr. Jiaming Ma explained that the innovation could transform how we think about sustainable construction.
“By simply using cardboard, soil and water, we can make walls robust enough to support low-rise buildings,” he said. “This approach removes the need for cement while still giving us the durability needed for practical use.”
The process is simple. At the building site, soil and water are packed into cardboard molds to form sturdy walls.
The thickness of the cardboard can be adjusted to change the strength of the structure, and the RMIT team has already developed formulas to calculate this relationship. That means builders can design structures with predictable levels of strength using only local resources.
Emeritus Professor Yi Min “Mike” Xie, co-author of the study, said the material could help construction become “leaner and greener.”
Instead of transporting heavy loads of bricks, steel, and concrete, builders would only need to carry lightweight cardboard. The rest of the material could be gathered directly from the building site. This would cut transportation costs, reduce logistics challenges, and minimize waste.
Cardboard-confined rammed earth could be especially useful in remote areas, where suitable soils are abundant but transporting conventional materials is expensive.
It also offers natural benefits: rammed earth walls have high thermal mass, meaning they keep buildings cool in hot climates and reduce the need for air conditioning.
In earlier research, Dr. Ma’s team also tested carbon fiber with rammed earth, achieving strength similar to high-performance concrete. Now, they are eager to partner with industries to further develop cardboard-confined rammed earth and bring it into mainstream construction.
This innovation not only reduces carbon emissions and waste but also reimagines how we can use everyday materials to build stronger, cleaner, and more affordable homes.
