Interest in obtaining a building material that can balance structural characteristics, cost and lower impact on the climate has come to play an important role today. In different parts of the world, tests are being carried out with alternative materials that make it possible to avoid the intensive use of cement, a component whose production has an impact on the environment that is difficult to ignore. In this context, a group of experts from RMIT University in Melbourne (Australia) has proposed a system that rethinks the technique of building with compacted earth, using a structure that utilises recycled cardboard tubes to retain the moistened and compacted earth. This proposal rejects the use of cement and offers a different approach to the creation of building material.
What is this new earth and cardboard-based building material like?
The method, called CCRE (Carton-Confined Rammed Earth), is based on the assumption that compacted earth can maintain its structural capacity if it is compacted in a recycled cardboard cylinder, which acts as reinforcement. This configuration eliminates the need for cement, which significantly reduces the carbon footprint compared to conventional concrete. The system itself uses familiar techniques, but adapts them to a modular construction that can be manufactured directly on site. According to tests published in the specialist journal Structures, the strength can be adjusted by increasing the thickness of the cardboard or adding additional reinforcement elements, such as carbon fibre. This makes it possible to create pieces with different strength characteristics, depending on the type of building or specific load requirements.
Why does this building material consume less energy?
The use of recycled cardboard as cladding offers another advantage: a reduction in the waste generated in the construction process.
For example, Australia sends more than 2.2 million tonnes of paper and cardboard to landfill each year. Integrating part of this flow into building materials, such as CCRE, would reduce the burden on the waste management system and, at the same time, reduce overall construction costs.
The production process is simple. Just mix earth and water, pour the mixture into a cardboard cylinder and compact it in layers. This technique does not rely on centralised factories and heavy transport, which broadens its applicability in remote regions or areas with limited infrastructure.
Compacted earth stands out for its ability to regulate internal temperature thanks to its thermal mass, which is useful in hot climates where the demand for cooling energy is high.
Productivity and potential of CCRE
The research group found that the structural integrity of CCRE is maintained even under significant loads. The combination of earth and cardboard prevents the cracks that normally appear in modern clay bricks when cement is not used.
In turn, the cylindrical reinforcement provides vertical stability and improves load distribution. This opens up possibilities for its use in low-rise buildings, where local solutions and easily accessible materials are valued.
In summary, here are the most notable features of the CCRE system:
- Use of earth and water as a structural base.
- Compaction with recycled cardboard.
- Resistance regulation by changing the thickness of the cardboard.
- On-site production with low-energy tools.
- Possibility of adding reinforcement materials, such as carbon fibre.
- Total recyclability of all components.
Initial tests show that this building material produces four times less emissions than conventional concrete and its production cost is less than a third of the cost of traditional concrete. Its potential lies in the fact that it does not require scarce resources or complex infrastructure, which facilitates its integration into projects of various sizes.
Towards a transition in construction systems
The growing interest in solutions such as hemp concrete or mycelium-based composites shows that the industry is looking for options with low environmental impact. However, CCRE stands out because it can be produced on site. This eliminates dependence on long logistics chains and reduces the time associated with the initial stages of construction.
The engineers responsible for the project say that the versatility of CCRE could make it a candidate for projects that require rapid construction and precise control of the ecological footprint.
Contacts have already been made with companies in the sector to conduct field tests and evaluate its behaviour in real buildings. In conclusion, it can be said that its development is taking place at a time when administrations and companies are looking for viable alternatives to traditional materials, which have high emission levels.