Engineers Develop Sustainable Building Material with Low Carbon Footprint

Innovative engineers at RMIT University in Australia have unveiled a groundbreaking building material that significantly reduces environmental impact. This new construction solution, known as cardboard-confined rammed earth, boasts a carbon footprint that is approximately one-quarter that of traditional concrete while also minimizing landfill waste.

This sustainable material is made by compacting a mixture of soil and water within cardboard tubes, eliminating the need for cement altogether. The resulting composite is strong enough to support low-rise buildings and can be manufactured directly on-site, making it particularly advantageous for construction in remote areas. Notably, the thermal properties of this material help to cool buildings naturally, enhancing energy efficiency.

The cardboard serves as permanent formwork, confining the rammed earth core and significantly improving its structural performance—by over tenfold, according to researchers. The process involves preparing soil through desiccation and sieving to manage moisture and grain size effectively. Engineers can create the material either manually or with the assistance of machinery.

Testing and Results

A key aspect of the development involves rigorous testing of different cardboard tube thicknesses. Researchers examined thicknesses of 1 mm, 2 mm, 3 mm, and 4 mm to determine how these variations affect the mechanical performance of the cylinders. All samples maintained a consistent height of 200 mm and an inner diameter of 100 mm. Each thickness category included three specimens for a series of repetitive tests.

The compression tests were conducted using a hydraulic testing machine at a constant loading rate of 500 Newtons. To calculate global strain, the displacement of the loading platen was divided by the initial height of the specimen. These findings contribute to the ongoing efforts in advancing building materials with lower carbon emissions.

Additionally, further research combined carbon fibre with rammed earth, demonstrating comparable strength to high-performance concrete. This combination enhances the material’s properties, making it even more suitable for modern construction.

Future Implications and Applications

The implications of this research are significant, especially for regions with hot climates. Buildings constructed using rammed earth can naturally regulate indoor temperatures and humidity levels, thereby reducing reliance on mechanical cooling systems. This not only cuts energy costs but also leads to a substantial decrease in carbon emissions associated with conventional construction methods.

The potential for cardboard-confined rammed earth extends beyond cost-effectiveness, as it can be produced for less than one-third of the price of concrete. The research team aims to push the boundaries of sustainable architecture, paving the way for greener and more resilient building solutions.

This innovative material is detailed in the journal Composite Structures, under the paper titled “CFRP-confined rammed earth towards high-performance earth construction.” With advancements like these, the construction industry may see a significant shift towards more environmentally friendly practices in the near future.

Dr. Tim Sandle, Digital Journal’s Editor-at-Large for science news, emphasizes that such innovations are vital in addressing the pressing challenges of climate change and resource management. The development of cardboard-confined rammed earth serves as a promising step towards a sustainable future in architecture.