A scientist in the Netherlands has created a self-healing concrete that can repair its own cracks. The amazing discovery was made by Henk Jonkers, a microbiologist who works in the field of civil engineering and conducts research at the Delft University of Technology.
What is the secret to Jonkers’ self-healing concrete? The clever scientist knew that certain bacteria produce limestone upon interacting with water and an organic nutrient known as calcium lactate. Jonkers mixes the bacteria and calcium lactate into concrete. Any water that seeps into a crack will “awaken” the bacteria, causing it to feed and secrete limestone which seals the fissure.
According to Jonkers, it only takes about three weeks for the bacteria to do its job and completely fill a crack of any length up to 8mm wide. The bacteria used by Jonkers is typically found in rocks near volcanoes, and is heat and cold resistant, making the concrete more durable.
Erosion is a huge problem in the building and engineering industries. While concrete is a popular construction material, stress cracks can occur over time, leading to the weakening of a structure, resulting in costly and time-consuming repairs. With reinforced concrete, as the water seepage erodes the concrete, it comes into contact with the steel inside, weakening the steel, which begins to corrode and become brittle. This usually happens in 20-30 years.
In addition to formulating bacteria-containing concrete, Jonkers and his team have also developed a repair mortar and a liquid that can be sprayed on traditional concrete. The liquid can be applied to existing structures and might even be used to preserve historical monuments that have been damaged or eroded over time.
The structural decay of buildings, tunnels, roadways, and bridges is not only unsightly but also potentially dangerous. Each year, countries around the globe spend billions of dollars on infrastructure repair. Jonkers believes that embracing sustainable construction is the answer.
“Nature has the capacity of self-healing. For example, if a tree loses a branch it can re-grow,” he explained, adding that the human body has similar self-healing capabilities. “But the built environment is dead, so this is what we are now changing,” he noted. Jonkers said he is looking to “minimize the impact of what we do with building,” while also working with the environment to improve and strengthen construction materials. “We can implement the living environment into the building environment,” he said.
Jonkers self-healing concrete is expected to substantially reduce maintenance and repair costs since buildings manufactured with the new concrete can begin to repair themselves before there’s any significant damage to a structure and continue to heal themselves for up to two centuries. “Nature has inspired us to produce this new type of material, a combination of biology and civil engineering bioconcrete, it will save us a lot of money which we would otherwise have to spend on maintenance and repair in the future,” Jonkers concluded.
The biggest obstacle for Jonkers and his team has been keeping the bacteria alive when it’s mixed into the concrete. The bacteria receive a special coating however this process is costly. Jonkers’ team is currently working to develop inexpensive methods to help the bacteria survive.
In addition to his academic work, Jonkers is also the research advisor for Basilisk Self-Healing Concrete. The company is affiliated with the Delft University of Technology and has struck multiple agreements to distribute Jonkers’ bioconcrete in countries around the globe.
Jonkers’ invention is definitely a game-changer in the field of engineering. He was a 2015 finalist for the European Inventor Award. “We think our concrete will revolutionize the way we build, because we’ve been inspired by nature. Plants and animals have the ability to heal and now we’ve given concrete the ability to do the same,” he said.