A team of engineers from RMIT University in Australia, developed a new building material that promises to revolutionize the industry, combining sustainability, low cost and efficiency. The compound, designated cardboard-confined compacted earth, is made only from earth, water and recycled cardboard — and features about a quarter of the carbon footprint of traditional concrete.
The innovation comes at a time when the construction industry is seeking greener alternatives in an effort to reduce global emissions. In Australia alone, more than 2.2 million tonnes of paper and cardboard end up in landfills every year. At the same time, the cement and concrete sector continues to be responsible for about 8% of global greenhouse gas emissions.
Inspired by projects such as the iconic Cardboard Cathedral, by Shigeru Ban, in New Zealand, the RMIT team joined the strength of compacted earth with the flexibility of cardboard, creating a viable solution for building low-rise structures.
“By using only earth, water and cardboard, we are able to build walls that are sufficiently strong, without the need for cement,” explains lead researcher Jiaming Ma. “This represents a significant saving of carbon and costs compared with conventional concrete,” he adds.
In addition to the reduced environmental impact, the new material can be produced directly at the construction site. The earth and water mixture is compacted inside cardboard molds, a process that can be performed manually or with simple machines. This method simplifies logistics and reduces transportation and material costs, especially in remote regions, where red soils — ideal for this type of construction — are abundant.
Emeritus Professor Yi Min “Mike” Xie, co-author of the study and expert in structural optimization, highlights the practical advantages of the technology: “Rather than transporting tons of materials such as concrete or steel, builders can use locally available resources. Just bring the cardboard needed for the molds,” he explains.
The strength of the material varies according to the thickness of the cardboard tubes used. The team developed a formula that allows calculating the robustness of the structure based on this parameter. According to Ma, the aim is to ensure structural safety with design flexibility.
In another complementary study, RMIT tested the integration of carbon fibre with compacted earth, obtaining results with strength similar to that of high-performance concrete.
The team is now seeking industry partners to scale up this technology. Interested companies can contact the university to collaborate on the development and application of the material.
