Engineers at the University of British Columbia (Vancouver, British Columbia, Canada) (UBC) have developed a more resilient type of concrete using recycled tires that could be used for concrete structures like buildings, roads, dams, and bridges—all while reducing landfill waste.
The researchers experimented with different proportions of recycled tire fibers and other materials used in concrete—cement, sand, and water—before finding the ideal mix, which includes 0.35% tire fibers, according to researcher Obinna Onuaguluchi, a UBC postdoctoral fellow in civil engineering.
Recycled-rubber roads are not new, according to the researchers, who explain that asphalt roads incorporating rubber “crumbs” from shredded tires exist in the United States, Germany, Spain, Brazil, and China. But using the polymer fibers from tires has the unique benefit of potentially improving the resilience of concrete and extending its lifespan, they say.
“Our lab tests showed that fiber-reinforced concrete reduces crack formation by more than 90% compared to regular concrete,” Onuaguluchi says. “Concrete structures tend to develop cracks over time, but the polymer fibers are bridging the cracks as they form, helping protect the structure and making it last longer.”
UBC civil engineering professor Nemy Banthia, who supervised the work, says the environmental and industrial impact of the research is crucial. Up to 3 billion tires are produced around the world every year—generating close to 3 billion kg of fiber when recycled, the researchers say.
“Most scrap tires are destined for landfill,” Banthia says. “Adding the fiber to concrete could shrink the tire industry’s carbon footprint and also reduce the construction industry’s emissions, since cement is a major source of greenhouse gases.”
Banthia also serves as scientific director at the UBC-hosted Canada-India Research Center of Excellence (IC-IMPACTS), a center that develops research collaborations between Canada and India.
“We use almost 6 billion cubic meters of concrete every year,” Banthia says. “This fiber can be in every cubic meter of that concrete.”
The new concrete was used to resurface the steps in front of a building on UBC’s campus earlier this year. Banthia’s team is tracking its performance using sensors embedded in the concrete and looking at the development of strain, cracking, and other factors. So far, the results support laboratory testing that shows it can significantly reduce cracking, according to the researchers.