A new building material developed at RMIT University combines cardboard, soil, and water to create a sustainable, low-cost alternative to concrete, offering significant reductions in carbon emissions and waste.
As global construction continues to grow, so do concerns over environmental impact. Cement and concrete production currently account for around 8% of global carbon emissions, while billions of tons of construction waste and cardboard end up in landfills annually. In Australia alone, more than 2.2 million tons of cardboard and paper are discarded each year. To address these issues, lead author Dr. Jiaming Ma from RMIT University has developed a novel building material known as cardboard-confined rammed earth, combining the durability of traditional rammed earth with the sustainability of recycled cardboard.
Ma, J., Zhang, H., Zhong, Y., Shobeiri, V., Ha, N. S., Venkatesan, S., Robert, D., & Xie, Y. M. (2025). Cardboard-confined rammed earth towards sustainable construction. Structures, 80, 110117. https://doi.org/10.1016/j.istruc.2025.110117
The material consists entirely of cardboard, soil, and water, making it both reusable and recyclable. The concept is inspired in part by temporary cardboard structures such as Shigeru Ban’s Cardboard Cathedral in Christchurch, New Zealand. However, RMIT’s approach introduces a permanent, load-bearing solution capable of supporting low-rise buildings.
Lead author Dr. Jiaming Ma from RMIT stated,
“This innovation could revolutionize building design and construction, using locally sourced materials that are easier to recycle. It also reflects the global revival of earth-based construction, fueled by net-zero goals and interest in local sustainable materials. By simply using cardboard, soil, and water, we can create walls robust enough to support low-rise construction. This could significantly change how we think about sustainable building materials, particularly in regions where local soils are readily available.”
The material offers several practical advantages for construction. The walls can be formed on-site by compacting a mixture of soil and water within cardboard formwork. This process can be performed manually or with machines, reducing transportation costs and material requirements compared to traditional concrete or masonry construction. It also allows builders to utilize locally sourced materials, a key consideration in remote or rural areas where heavy construction materials may be difficult or expensive to transport.
Emeritus Professor Yi Min “Mike” Xie, a co-author and structural optimization expert, highlighted the logistical benefits: “Instead of hauling tons of bricks, steel, or concrete, builders only need to transport lightweight cardboard, as most of the material comes from local soils. This reduces costs and simplifies construction.”
The material’s mechanical strength depends on the thickness of the cardboard tubes used in the formwork. The RMIT team has developed formulas to calculate wall strength based on tube thickness, allowing engineers to design with confidence. This ensures that the material can meet structural requirements for a variety of low-rise applications, including residential buildings, community centers, and small commercial structures.
Beyond cardboard, the researchers also explored carbon fiber-reinforced polymer (CFRP)-confined rammed earth, published in Composite Structures, demonstrating that this variation can achieve strengths comparable to high-performance concrete. This suggests potential applications in projects where higher structural loads or durability are required.
Cardboard-confined rammed earth also benefits from high thermal mass, helping regulate indoor temperatures and humidity without mechanical cooling. This passive climate control reduces energy consumption, further lowering the building’s overall environmental footprint—a critical advantage in hot climates common to many parts of Australia.
The RMIT team is now seeking partnerships with industry to scale and implement the material in real-world projects. Potential applications extend beyond urban areas to remote regions, where sustainable, low-cost construction materials are particularly valuable. By integrating recycled cardboard and local soils, this innovation contributes to a circular economy and supports net-zero building initiatives worldwide.
As sustainability becomes an increasingly central focus for the construction industry, cardboard-confined rammed earth offers a tangible, low-carbon alternative to conventional concrete. Its combination of affordability, environmental benefits, and practical performance positions it as a promising material for the next generation of sustainable construction projects.
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
