Today, most houses, buildings, and infrastructures rely heavily on cement and concrete. Yet this material comes at a high environmental cost. Cement production alone is responsible for nearly 8% of global carbon dioxide emissions every year. At the same time, enormous quantities of cardboard and paper are discarded daily, often without any form of reuse. This contrast has pushed researchers to rethink how we build and to question the true role of cement in modern construction.
Facing the cement issue
Researchers from RMIT University in Australia set out to explore a more sustainable alternative. Their key question was simple but ambitious: is it possible to build strong structures without cement while reusing materials that already exist? To answer this, they turned to two basic and widely available resources: soil and cardboard.
This research led to the creation of two innovative construction materials that eliminate cement entirely. These solutions aim to reduce pollution, improve structural performance, and lower costs. Both materials rely on the same core principle: rammed earth, a technique that involves compressing damp soil until it becomes dense and solid.
What differentiates the two approaches is the outer casing that surrounds the compacted earth:
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Rammed earth inside recycled cardboard tubes
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Rammed earth inside carbon fiber tubes
In both cases, the objective is the same: achieve strength and durability while significantly reducing environmental impact.
Back to earth as a construction material
Using earth as a building material is far from a new concept. For centuries, civilizations around the world have constructed homes from rammed earth, benefiting from its natural ability to regulate indoor temperatures. Buildings made this way remain cool in summer and warm in winter, reducing the need for artificial heating or cooling.
Over time, however, industrial construction methods pushed earth aside in favor of cement and concrete. Today, with climate change accelerating, interest in earth-based building techniques is resurfacing.
Soil is widely available and does not require energy-intensive industrial processing like cement. Its main limitation is structural: when used alone, it can crack or fail under heavy loads. The researchers overcame this issue by enclosing the earth within a tubular structure. This external “jacket” prevents expansion and cracking, greatly improving strength without the need for cement.
First option: using recycled cardboard tubes
The first solution targets smaller structures, such as low-rise housing. It combines compacted soil, water, and recycled cardboard tubes. The cardboard plays a dual role, acting both as a mold during construction and as a permanent structural element.
The result is a surprisingly solid and stable material, capable of competing with traditional cement-stabilized earth. Most importantly, its environmental footprint is dramatically lower, with up to 80% less carbon emissions compared to conventional concrete.
Second option: using carbon fiber tubes
The second approach replaces cardboard with carbon fiber tubes. Carbon fiber is known for its exceptional strength and low weight, which is why it is commonly used in aerospace and high-performance vehicles.
When paired with rammed earth, carbon fiber creates structural columns that nearly match the strength of high-grade concrete while being significantly lighter and more sustainable. This solution is particularly suited for areas requiring strong yet lightweight construction, such as earthquake-prone regions.
Although carbon fiber is more expensive than cardboard, its performance advantages make it a compelling option for specific applications.
So…
While long-term studies are still needed to fully assess durability over decades, the early findings are extremely encouraging. These innovations demonstrate that it is possible to build in a more responsible way, combining natural materials, recycled resources, and smart design to drastically reduce the environmental impact of construction.
They also prove that the future of building may not lie in new materials, but in rethinking how we use the ones we already have.
