Ingeniously simple and inspired by nature, this “self-healing” concrete could mean cracked roads and potholes will soon become a thing of the past.
Researchers at Binghamton University in New York have been working on a concrete that’s able to fill in its cracks using Trichoderma reesei, a fungus first isolated from a piece of cotton canvas in the Solomon Islands during World War II. Best of all, the solution is low cost and pollution-free. Their breakthrough was recently published in the academic journal Construction & Building Materials.
Crumbling concrete begins with micro-cracks. Water and air can seep into these barely visible cracks, where they expand and eventually make the cracks grow deeper and longer. This fungus lays dormant in the concrete until cracks appear and it meets water and air, at which point the fungus will “bloom” and fill in the crack.
“The fungal spores, together with nutrients, will be placed into the concrete matrix during the mixing process,” assistant professor Congrui Jin, study author, explained in a statement.
“When cracking occurs, water and oxygen will find their way in. With enough water and oxygen, the dormant fungal spores will germinate, grow and precipitate calcium carbonate to heal the cracks.”
“When the cracks are completely filled and ultimately no more water or oxygen can enter inside, the fungi will again form spores. As the environmental conditions become favorable in later stages, the spores could be wakened again.”
Cracks in the concrete are a big enough problem when you think about roads and city infrastructures. However, it could be truly dangerous in some instances, such as in a nuclear power plant.
Like all the best inventions, Jin explains, the solution was inspired by the way animal tissues can health themselves from cuts and broken bones.
The project still has a long way to go before it hits the market, as the researchers are still working on the survivability of the fungus in the rather unfavorable environment of concrete. Nevertheless, based on these promising results, the team are now confident that further investigations with other fungi or yeasts will reveal the key missing ingredient.