Jun. 5, 2025 - Low-grade clay, previously overlooked in construction, can significantly reduce the carbon footprint of concrete, a new Australian study revealed on Thursday.

Researchers at the Royal Melbourne Institute of Technology (RMIT) have developed an innovative process that transforms abundant, low-value illite and kaolin clays into a high-performance cement substitute, said a RMIT news release.

This breakthrough offers a practical and scalable solution to one of the construction industry’s biggest environmental challenges, as cement production currently accounts for 8 percent of global CO2 emissions, the release said.

Cement production traditionally relies on scarce high-grade kaolin clay, a resource increasingly used in cosmetics and ceramics. RMIT researchers now propose a solution using abundant, lower-quality materials, it said.

By mixing underutilized illite clay with low-grade kaolin and heating the blend at 600 degrees Celsius, the team created a cement substitute that replaces 20 percent of traditional cement while boosting concrete’s compressive strength by 15 percent and slashing porosity by 41 percent, researchers said.

With global kaolin demand projected to hit 6 billion U.S. dollars by 2032, the method could spark parallel markets for illite clay, the study predicted.

“Since raw materials are processed together, it streamlines industrial operations and lowers fuel use compared to multiple calcination steps,” said the study’s lead author Roshan Jayathilakage from RMIT.

A new AI-driven computational tool, developed with Japan’s Hokkaido University, accelerates the design of region-specific clay-concrete mixes by analyzing durability and energy efficiency, according to the study published in Construction and Building Materials.

The team, collaborating with the European Synchrotron Radiation Facility, is now expanding performance testing under real-world conditions.