Fungal concrete promises sustainable solution to building repair
Researchers developing a technique for mixing fungal spores with concrete say their work could result in self-healing buildings that are able to mend their own cracks as they appear.
Structural problems can start with the smallest of cracks. Without proper treatment, they grow, eventually requiring expensive repairs and possibly exposing steel reinforcement to water and oxygen, leading to corrosion. Surfaces can be remade to replace ageing materials, but this is often just a short-term fix and more cracks inevitably appear.
Researchers at Binghamton University, State University of New York, believe they’ve found a possible permanent solution in the shape of a fungus called Trichoderma reesei.
Congrui Jin, assistant professor of mechanical engineering at Binghamton, says the inspiration came from the human body’s ability to heal cuts, bruises and broken bones. Working with professor Guangwen Zhou and associate professor David Davies, both from Binghamton University, and associate professor Ning Zhang from Rutgers University, she found that fungal spores added to a concrete matrix during the mixing process remain dormant until a crack appears.
As water and oxygen find their way into a structure, the spores germinate, grow and precipitate calcium carbonate that ‘heals’ any fissures. When the cracks are completely filled and no more water or oxygen can enter, the fungi again form spores until further deterioration causes them to be reactivated.
The research reported in the journal Construction and Building Materials is still in its early stages, with the biggest issue still to be addressed being the survivability of the fungus within the harsh environment of concrete. However, Jin is hopeful that with further adjustments the Trichoderma reesei will be able to effectively fill the cracks.
"There are still significant challenges to bring an efficient self-healing product to the concrete market,” she said. “In my opinion, further investigation in alternative microorganisms such as fungi and yeasts for the application of self-healing concrete becomes of great potential importance."