In the global effort to reduce carbon emissions in construction, researchers at RMIT University in Australia have unveiled a promising development: a stronger, more environmentally friendly concrete created from low-grade clay. This approach could transform the use of available and less expensive materials in the cement industry. cement industrywhich currently contributes 8% of global CO₂ emissions.
Lower emissions and better performance
Instead of using high-purity kaolin, which is in increasing demand for its application in ceramics, cosmetics and paper, the RMIT team mixed low-grade kaolin with illite, a clay that is also underrated.
The mixture was calcined at 600 °C in a joint process, resulting in increased pozzolanic reactivity. According to Dr. Chamila Gunasekara, this combination made it possible to replace up to 20% of traditional cement without compromising concrete performance.
Structural benefits from the use of low quality clay
The new material exhibited significant improvements: porosity was reduced by 41%, compressive strength increased by 15% and 18% more disordered material beneficial to durability was recorded. In addition, the composite retains more water in a stable form, improving long-term reactions that strengthen the internal structure.
This breakthrough is supported by a computational tool developed by RMIT and Hokkaido University, which evaluates the behavior of concrete based on different clay mixtures. Dr. Yuguo Yu explained that this platform reduces the need for extensive laboratory testing, optimizing formulations according to clay types and local conditions.
Towards a circular construction
This work is part of the TREMS Center, led by Professor Sujeeva Setunge, which drives sustainable industrial solutions using recovered waste. Collaboration with international institutions, such as the European Synchrotron Radiation Facility, is enabling research to be scaled up under real-world conditions. The market for kaolin is estimated to reach $6 billion by 2032, which could open up new opportunities for illite clay.
With this innovative approach, the concrete industry could take a firm step towards a more sustainable and resilient economy. This finding has been published in the specialized journal Construction and Building Materials of ScienceDirect.
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Source and photos: RMIT
