Construction materials company Boral has completed product development for a low-carbon concrete using Australian calcined clay.
The company says that it’s the first time that an Australian company has achieved this milestone, a move that will reduce carbon emissions in concrete production and infrastructure.
It follows extensive laboratory testing and large-scale field trials, demonstrating the viability of calcined clay as a supplementary cementitious material (SCM).
The calcined clay concrete mixes comprise binary- and triple-blend formulations.
These were tested under real-world conditions at Boral’s cement operations in Maldon and successfully demonstrated workability and comparable performance to traditional low-carbon concrete.
The field trials followed customer trials where Boral collaborated with Victoria’s North East Link and the University of Melbourne to supply a concrete mix for a test slab.
The calcined clay concrete test slab used clay recycled from excavated soil from the same site.
“From the lab to successful field trials and product development, our work demonstrates that calcined clay concrete is not just a concept; it works at scale. Our field trials confirmed workability and placement and the concrete looks and performs like conventional mixes,” Boral head of Sustainability and Innovation Dr Ali Nezhad says.
“In developing a range of next-generation low-carbon concrete products with different blends, we are future-proofing supply and supporting the industry’s decarbonisation goals.”
Last year, Boral acquired Wallan Concrete plant, 45km north of Melbourne, for an undisclosed sum. The acquisition provided Boral with additional ability to service customers in Melbourne’s outer north growth corridor and complement the existing concrete batching plant and quarry at Wollert.
Globally, about 25 billion tonnes of conventional concrete is used every year, and it consumes about 30 percent of non-renewable natural resources, emitting about eight percent of atmospheric greenhouse gases.
Teams in other parts of Australia are working toward finding ways to reduce the environmental impact of concrete. Last year, a group of researchers from Flinders University found an innovative way to repurpose mining waste and use it in the production of concrete.
They found that Delithiated β-spodumene (DβS), a rare earth by-product of lithium refining, exhibited pozzolanic properties. That property means that the material reacts chemically to enhance the strength and durability of concrete.
The research demonstrated an effective way to incorporate DβS as an alternative ingredient to fly ash (a coal combustion by-product) in the creation of geopolymer binders.
Read more: Flinders University researchers use mining waste in concrete production
