North East Connected

Teesside University academics preparing self-healing concrete

Screen Shot 2016-05-03 at 12.35.15Bacteria could be used to repair our buildings and structures in the future thanks to innovative research being carried out at Teesside University.

An inter-disciplinary team of engineers and scientists at the University is investigating how to use micro-organisms to self-heal damaged concrete as part of a ground-breaking project which could eventually save developers, public authorities and Governments millions of pounds in future maintenance costs.

The research could even save lives in areas which are prone to natural disasters.

The team is looking at how concrete can be infused with eco-friendly bacteria which secrete chemicals and seal up cracks as they form on the building material, in a project funded by the University Research Fund.

Chandra Vemury, a Senior Lecturer in Structural Engineering, said: “Concrete is the second most widely used material on the planet, after water, due to its high compressive strength and the ease with which it’s prepared.

“However, the limited tensile strength of concrete causes it to undergo cracking.

“The maintenance of concrete structures is usually very expensive. For example, Transport for London has spent nearly £70 million since 2011 to repair and strengthen the Hammersmith Flyover.”

A conventional solution to deal with this problem is to reinforce pre-stressed concrete with steel.

Nevertheless, this does not completely prevent or reseal cracks formed. Engineers at the University have teamed up with biotechnologist, Dr Pattanathu Rahman, to come up with a solution through bacterial addition to fix the cracks.

Dr Rahman said: “A group of bacteria called chemo-lithotrophs can survive in harsh conditions without food and water by creating a capsule around them.

“When a crack is opened in the concrete, the capsule opens and they return to life. In doing so, they secrete biochemicals which begin a healing process in the concrete.

“These chemicals form protective organic polymers which fill hairline cracks in concrete with biosynthesised inorganic minerals and can strengthen concrete structures.”

The team is testing the concept of using bacteria to repair concrete cubes by mixing cement, sharp sand and aggregates with water. These concrete cubes then have bacteria added to self-heal internal cracks.

Dr Manu Ramegowda, a Senior Lecturer in Engineering, said: “This study includes looking at the structure of the repaired concrete and the role of biology in the healing process.

“This technology could be used to strengthen concrete structures in earthquake prone areas.”

Dr Carlos Insaurralde, a Senior Lecturer in Control and Instrumentation Engineering, added: “One of the main challenges is the diagnosis and even prognosis of the bacterial concrete health.

“The biologically-inspired solution proposed for concrete self-healing/self-repairing creates a good opportunity to envisage homeostatic monitoring methodologies in order to assess the concrete well-being.”

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