Researchers have created stronger and more durable concrete using a surprising ingredient: scrap carpet fibers.
RMIT University in Australia has discovered this new way to convert waste carpet fibers into a key component for crack-resistant concrete.
Australia spends a hefty $8 billion annually on repairing cracked concrete structures. Meanwhile, the US spends a whopping $76 billion annually on concrete repairs.
This underlines the need for innovative solutions to prevent and repair these cracks, which can weaken structures and compromise safety.
“Scrap carpet fibers can be used to increase the strength of concrete by 40% in tensile strength and prevent premature cracking by significantly reducing shrinkage,” said Chamila Gunasekara, the lead researcher.
30% reduction in cracks
This innovative approach tackles a major problem in the construction sector: squatting at a young age. By reducing shrinkage, the new concrete formulation improves durability and extends the lifespan of structures.
Interestingly, the new technique significantly reduced concrete cracking at a young age, by up to 30%.
“Cracks in early-age concrete slabs are a long-standing challenge in construction projects that can cause premature corrosion, not only making a building look poor but also compromising its structural integrity and safety,” Gunasekara added.
For now, the researchers have created laboratory concrete samples from discarded materials. These textile reinforced concrete samples met Australian Standards for technical and environmental criteria.
Discarded firefighter clothing can also be used
The researchers emphasize the major environmental impact associated with the disposal of carpets and other textiles.
Carpets are often made of synthetic materials such as nylon, polyester and polypropylene. These materials contain various chemicals, including flame retardants, dyes and adhesives. When burned, these chemicals decompose and release toxic gases into the atmosphere.
Furthermore, burning carpet waste outdoors results in the contamination of soil and water with toxic ash and particulate matter.
“Australia is the second largest consumer of textiles per person in the world, after the US. The average Australian buys 27kg of new clothing and textiles every year and throws 23kg into landfill,” Gunasekara said.
In addition to carpets, the team is also investigating the use of other textile waste, such as discarded clothing and firefighting equipment, to further improve the performance of concrete.
Shadi Houshyar, textile and materials scientist at RMIT, highlighted the challenge of recycling firefighter clothing. The very properties that make these materials firefighting heroes, such as their flame resistance and durability, make them recycling villains.
“Up to 70% of textile waste could be suitable for conversion into useful fibers, offering opportunities in the materials supply chain,” Houshyar said in the press release.
Standard concrete production is energy intensive and contributes to significant CO2 emissions. However, this new method is sustainable.
It reduces waste and significantly improves the properties of the concrete. It’s a double win for the environment and construction.
The researchers then want to conduct field tests and computational modeling of this concrete mixed with carpet fibers. Field tests will allow assessment of the performance of the concrete under actual construction conditions.
By working together with industry and local governments, the researchers want to accelerate the adoption of this sustainable solution.
The findings have been published in the Construction and building materials magazine.
