As temperatures swing through winter, Canada’s concrete roads, bridges, and buildings begin to crack. Those cracks allow water and chemicals to seep in, weakening structures and driving up maintenance costs. Engineers are now asking whether concrete can be redesigned to heal itself, much like human skin, and extend the lifespan of critical infrastructure, tells this The Conversation article.
Concrete is durable but vulnerable. It’s made from cement, water, and aggregates, and small changes during mixing, placement, or exposure to the environment can create cracks. These openings compromise long-term strength, which is why researchers are exploring self-healing concrete.
Traditional concrete can mend hairline cracks through autogenous healing, where water activates leftover cement. But the process is slow and limited. This led to autonomous healing, in which materials such as minerals, polymers, or microorganisms are embedded into the concrete to react when cracks form.
Early breakthroughs came from Carolyn Dry in the 1990s and from Hendrik Jonkers and Erik Schlangen, whose “bio-concrete” used dormant bacteria that activate when moisture enters a crack. The bacteria produce calcium carbonate to fill gaps up to one millimeter wide. While promising, this biological method is slow and depends heavily on moisture and chemical availability inside the concrete.
Chemical-based healing mechanisms emerged to address those limits. Some use single agents such as sodium silicate; others rely on two-part systems that trigger a reaction when both components are released. These approaches work faster and can handle larger cracks but require protective storage to prevent premature reactions. Researchers use vascular networks or encapsulation—micro-capsules with polymer shells that rupture only when the concrete cracks.
At McMaster University, teams are studying capsule geometry, mechanical strength, and survival during mixing. They are also standardizing methods to measure healing performance and exploring combinations of biological and chemical healing.
Self-healing concrete won’t eliminate maintenance, but it could significantly reduce repairs, extend infrastructure life, and lower costs for communities.