InfrastructureDamage-sensing, self-repairing concrete
Skin is renewable and self-repairing — our first line of defense against the wear and tear of everyday life. If damaged, a myriad of repair processes spring into action to protect and heal the body. Clotting factors seal the break, a scab forms to protect the wound from infection, and healing agents begin to generate new tissue. Taking inspiration from this remarkable living healthcare package, researchers are asking whether damage sensing and repair can be engineered into a quite different material: concrete. Their aim is to produce a “material for life,” one with an in-built first-aid system that responds to all manner of physical and chemical damage by self-repairing, over and over again.
Roads that self-repair, bridges filled with first-aid bubbles, buildings with arteries… not some futuristic fantasy but a very real possibility with ‘smart’ concrete.
Skin is renewable and self-repairing — our first line of defense against the wear and tear of everyday life. If damaged, a myriad of repair processes spring into action to protect and heal the body. Clotting factors seal the break, a scab forms to protect the wound from infection, and healing agents begin to generate new tissue.
Taking inspiration from this remarkable living healthcare package, researchers are asking whether damage sensing and repair can be engineered into a quite different material: concrete.
Their aim is to produce a “material for life,” one with an in-built first-aid system that responds to all manner of physical and chemical damage by self-repairing, over and over again.
A University of Cambridge release reports that self-healing materials were voted one of the top-ten emerging technologies in 2013 by the World Economic Forum, and are being actively explored in the aerospace industry, where they provide benefits in safety and longevity. Perhaps one area where self-healing might have the most widespread effect, however, is in the concrete-based construction industry.
Concrete is everywhere you look: in buildings, bridges, motorways, and reservoir dams. It is also in the places you cannot see: foundations, tunnels, underground nuclear waste facilities, and oil and gas wells. After water, concrete is the second most consumed product on earth; ton for ton, it is used annually twice as much as steel, aluminum, plastic and wood combined.
Like most things, however, concrete has a finite lifespan. “Traditionally, civil engineering has built-in redundancy of design to make sure the structure is safe despite a variety of adverse events. But over the long term, repair and eventual replacement is inevitable,” said Professor Abir Al-Tabbaa, from the Department of Engineering and the lead of the University of Cambridge component of the research project.
The United Kingdom spends around £40 billion per year on the repair and maintenance of existing, mainly concrete, structures. However, repairing and replacing concrete structures cause disruptions and contribute to the already high level of carbon dioxide emissions that result from cement manufacturing. What if the life of all new and repaired concrete structures — and in fact any cement-based material, including grout and mortar — could be extended from an average of several decades to double this, or more, through self-healing?
