Engineers Created Concrete That Heals Its Own Cracks Using Bacteria Inside the Mix

Concrete is the most-used material on Earth after water. It is also one of the most fragile in long-term use — cracks let in water, which corrodes reinforcing steel, which causes more cracks, which causes failure. Repairing it is expensive. So Hendrik Jonkers, a Dutch microbiologist, asked a strange question: what if concrete could heal itself?

His solution: embed dormant Bacillus pseudofirmus bacteria — and a calcium lactate food source — directly into the concrete mix. The bacteria can survive in spore form for over 200 years. When water seeps into a crack, the bacteria activate, consume the calcium lactate, and excrete limestone — sealing the crack within weeks.

Why It Matters

• Concrete failures are responsible for billions in annual repair costs worldwide
• Self-healing concrete could double the lifespan of structures
• It could dramatically reduce the construction industry's carbon footprint (cement production accounts for 8% of global CO₂)
• It can be used in places where repairs are difficult — bridges, tunnels, underwater structures

Self-healing concrete is now in commercial use in projects across Europe, including parts of major bridges and tunnels.