Making and testing energy-smart bricks
Regular bricks are made of clay, water, and sand. However, energy-smart bricks use 20 percent coal ash and 15 percent fine glass waste. This RCF waste is mixed with crushed clay particles and then oven-dried. Water is then added to the dried mixture, resulting in the production of green-colored bricks that are air-dried for 48 hours.
Next, the bricks are placed in a furnace where they are fired at 950° C, eventually turning into the desired energy-smart bricks. “We can also produce light-weight bricks in a range of colors from white to a dark red by changing our formulations,” Dilan Robert, one of the researchers and an associate professor at RMIT, said.
The team tested the strength and durability of the bricks, comparing them to regular clay bricks. When they measured the compressive strength of the latter, the bricks withstood 23.1 Megapascal (MPa) before failing. However, for bricks with 15 percent glass waste, it was 31.6 MPa, indicating higher durability and strength.
“Over 100 bricks were manufactured under different firing temperatures and tested in this study to ensure comprehensive compliance against construction standards. All bricks manufactured and fired at 950° C using RCF waste exceeded the industry's compliance and standards, demonstrating their suitability in construction,” the study authors note.
The energy-smart brick manufacturing process also meets the key compliance requirement of fired clay bricks set by Standards Australia. Moreover, “the use of RCF wastes in brick production offers potential for reducing greenhouse gas emissions, with a 7 percent reduction compared to control bricks,” the study authors added.
Time for mass production?
It took RMIT researchers four years to arrive at the perfect energy-smart brick formulation; they had started working on energy-smart bricks in 2020. To arrange the RCF waste for their experiments, they collaborated with Visy, an Australia-based company that specializes in recycling rejected glass waste into new glass packaging.
Visy was struggling to find a way to use glass pieces smaller than 3 millimeters in size. It was not possible to make new glass products using these pieces, and most of them ended up in landfills. So when the RMIT team approached them with the idea of energy-smart bricks, “the company was thrilled to find a solution for material that cannot be recycled into food and beverage packaging,” Paul Andrich, a Visy representative, said in a press release.
Energy-smart bricks are now ready for use, but there are still some challenges left for the researchers. For instance, they have only produced a limited number of bricks in the lab. Whether mass-produced bricks are as energy-efficient, eco-friendly, and commercially viable as the lab samples will be a critical question.
“We are focusing on scaling up the production process to facilitate the commercialization of our innovative bricks in collaboration with brick manufacturers in Melbourne,” Robert said.
Construction and Building Materials, 2024. DOI: 10.1016/j.conbuildmat.2023.134031 (About DOIs)
Rupendra Brahambhatt is an experienced journalist and filmmaker. He covers science and culture news, and for the last five years, he has been actively working with some of the most innovative news agencies, magazines, and media brands operating in different parts of the globe.
Listing image by Seamus Daniel, RMIT University
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