Engineers in Australia have developed a groundbreaking building material that has about one-quarter of the carbon footprint of concrete, while also minimizing waste headed to landfills.
This innovative material, known as cardboard-confined rammed earth, is made entirely from cardboard, water, and soil—making it both reusable and recyclable.
In Australia, over 2.2 million tons of cardboard and paper end up in landfills each year. Additionally, cement and concrete manufacturing is responsible for about 8% of global annual emissions.
Previously, cardboard has been utilized in temporary structures and disaster shelters, such as the famous Cardboard Cathedral designed by Shigeru Ban in Christchurch, New Zealand.
Inspired by these projects, the team from RMIT University has combined the robust qualities of rammed earth with the flexibility of cardboard for the first time.
Why it matters
Dr. Jiaming Ma, the lead author from RMIT, emphasized that the creation of cardboard-confined rammed earth represents a significant step toward a more sustainable construction industry.
“Traditionally, rammed earth construction involves compacting soil with added cement for strength. This reliance on cement is problematic, given the inherent sturdiness of rammed earth walls,” he explained.
However, the new cardboard-confined rammed earth eliminates the need for cement and has only one-quarter of the carbon footprint at less than one-third the cost of concrete.
“By using just cardboard, soil, and water, we can create walls strong enough to support low-rise buildings,” Ma noted.
“This innovation could transform building design and construction, utilizing locally sourced materials that are easier to recycle.”
“It’s a part of the global trend toward reviving earth-based construction, driven by net-zero goals and a focus on sustainable local materials.”
Practical benefits
Cardboard-confined rammed earth can be constructed directly on-site by compacting the soil and water mixture inside cardboard molds, using either manual labor or machinery.
Emeritus Professor Yi Min ‘Mike’ Xie, the study’s corresponding author and a leading expert in structural optimization, believes this development can lead to a more efficient and eco-friendly approach to construction.
“Rather than hauling in tons of bricks, steel, and concrete, builders would only need to transport lightweight cardboard, with most materials sourced from the site,” Xie said.
This change would dramatically lower transport costs, streamline logistics, and reduce initial material requirements.
Dr. Ma mentioned that cardboard-confined rammed earth could be ideal for construction in remote areas, like regional Australia, where red soils—perfect for rammed earth—are abundant.
“Rammed earth buildings work well in hot climates because their high thermal mass helps maintain indoor temperatures and humidity, minimizing the need for mechanical cooling and reducing carbon emissions,” he added.
The strength of this novel material can be adjusted based on the thickness of the cardboard tubes used.
Ma explained, “We’ve figured out how cardboard thickness impacts the strength of the rammed earth, allowing us to gauge strength effectively.” In a separate study led by Ma, the addition of carbon fiber to rammed earth demonstrated strength that rivals high-performance concrete.
Ma and his team are prepared to collaborate with various industries to further develop this new material for widespread use.
Summary: Engineers in Australia have created a new environmentally friendly building material, cardboard-confined rammed earth, which utilizes cardboard, water, and soil. This innovative approach significantly reduces carbon emissions and waste, paving the way for a sustainable construction industry, especially in remote areas. With the potential to rival traditional materials, this development marks a transformative step toward eco-friendly architecture.
