Scientists Create ‘Living Concrete’ That Repairs Its Own Cracks

Concrete remains a widely used and highly adaptable construction material, but it has notable drawbacks—particularly its tendency to crack due to low tensile strength. To address this vulnerability, researchers have been exploring ways to develop concrete that can repair itself, and a new innovation might be a significant breakthrough.

A Self-Healing Breakthrough Using Synthetic Lichen

A team led by mechanical engineer Congrui Grace Jin at Texas A&M University has created a type of concrete capable of self-repair by leveraging synthetic lichen. This new method stands apart from previous efforts, which often relied on bacteria, by being fully self-sustaining.

“Although microbe-based self-healing concrete has been explored for over 30 years,” Jin explains, “the major issue is that none of these techniques function entirely on their own—they still rely on an external supply of nutrients to trigger the repair process.”

For example, bacterial systems often require manual application of nutrients to stimulate healing activity. In a recent study led by first author Nisha Rokaya from the University of Nebraska-Lincoln, the researchers introduced an alternative approach that goes a step further.

The Science Behind Synthetic Lichen

Lichen, which isn’t a single organism but a symbiotic combination of fungus and either algae or cyanobacteria, served as the foundation. The team engineered a custom lichen featuring cyanobacteria that extract carbon dioxide and nitrogen from the air, paired with filamentous fungi that attract calcium ions and facilitate the creation of calcium carbonate—the same substance found in seashells, coral, and chalk.

In lab tests, the synthetic lichen successfully repaired cracks by depositing significant amounts of calcium carbonate, effectively bonding the fissures and halting further damage. This process is reminiscent of the self-repair mechanism seen in ancient Roman concrete, which also relies on calcium carbonate formation.

A Fully Autonomous Solution

Unlike bacterial methods, this bioengineered lichen doesn’t require human intervention or additional feeding—it operates independently once in place.Researchers see promising potential to extend the durability of concrete infrastructure, though they still need to study how the material performs when repairing pre-existing cracks.

The study shows that it’s possible to create a stable phototrophic-heterotrophic system for self-sufficient concrete repair,” the researchers wrote. “It uses the capabilities of two organisms at once, removing the need for external nutrient input.

Read the original article on: Science Alert

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