Scientists Find Cure for Concrete Cancer
In a recent study, Canadian researchers reported the ability to calm a chemical reaction that has traditionally caused glass-fed concrete to weaken, expand and crack, a reaction known as “concrete cancer.”
The team from the University of British Columbia Okanagan campus reports it has found a more reliable way to make concrete from discarded glass, the university announced Wednesday (May 25).
The findings were recently published in the journal Construction and Building Materials.
A Step Forward
“Every year, millions of tons of glass bypass recycling centres and end up in North American landfills,” explained Associate Professor of Engineering Shahria Alam. “Like many engineers, we are interested in making smarter building materials that can give the construction industry the resources they need without necessarily having to take new resources out of the ground.”
Alam said that researchers have been on the lookout for ways to reliably make use of glass in concrete construction. He said his team’s research represents a significant step forward in the search.
Concrete cancer occurs when the alkaline properties in cement paste react with silica properties that can occur in recycled concrete additives, such as glass, the university reports.
In their study, Alam and co-researcher Anant Parghi discovered that by adding a water-based, synthetic rubber polymer, fly ash, and silica powder to the concrete mixture, they were able to effectively neutralize negative chemical reactions.
“By partially replacing cement with polymer, fly ash and glass powder, we were able to produce concrete that was more than 60 percent stronger than what was previously believed possible,” said Parghi. “Though further testing is needed to assess long-term stability, it now looks like we can replace up to 25 percent of the cement materials that had to be mined for cement production with glass.”
All of the glass used in the study was taken from the landfill in Kelowna, BC, and was considered waste at the time it was retrieved. The concrete additives were donated from Kelowna-based company POLYRAP Engineered Concrete Solutions.