Self-healing Concrete using Bacteria to prevent ingress of water.
- Self-healing Concrete using Bacteria to prevent ingress of water.
Micro-capsules and bacteria to be used in self-healing concrete
30 May 2013
A new research project involving researchers from Bath aims to develop
novel self-healing concrete that uses an inbuilt immune system to
close its own wounds and prevent deterioration.
The life of concrete structures is reduced when the material cracks
and water is able to get at the steel reinforcement, causing rust and
The project is funded by a £2m EPSRC grant, matched by an additional
industrial contribution of just over £1 million, and will involve our
researchers in collaboration with Cardiff University (the lead
partner) and the University of Cambridge.
Our team here at Bath aims to develop a concrete mix that contains
bacteria within microcapsules, which will germinate when water enters
a crack in the concrete to produce limestone (calcite), plugging the
crack before water and oxygen has a chance to corrode the steel
Self-healing concrete could vastly increase the life of concrete
structures, and would remove the need for repairs, reducing the
lifetime cost of a structure by up to 50 per cent.
Over seven per cent of the world’s CO2 emissions are caused by cement
production, so reducing the amount required by extending the lifetime
of structures and removing the need for repairs will have a
significant environmental impact.
Dr Richard Cooper, from the Department of Biology & Biochemistry,
said: “Cement is highly alkaline, making it a hostile environment for
bacteria. We’ll be assessing different species of bacteria to find one
that is able to form abundant spores and which will survive and
germinate in this environment. The work will involve finding
alkaline-tolerant isolates and testing their biology and physiology.”
Dr Kevin Paine, from the Department of Architecture & Civil
Engineering, said: “Concrete densifies as it hardens, so the pore size
decreases to a level where bacteria may be crushed. We’re looking at
enclosing the bacteria in micro-capsules, along with nutrients and
calcium lactate which the bacteria will convert when water becomes
present and use to fill cracks in the concrete.”
Dr Andrew Heath, also from the Department of Architecture & Civil
Engineering, said: “Self-healing materials are particularly suited to
situations where safe access for maintenance is costly, so the outputs
of this extended research programme could reduce the life-cycle costs
Dr Cooper added: “Including bacteria in concrete offers a double layer
of protection in preventing steel corrosion. Not only do the bacteria
work to plug cracks in the concrete, the process of doing so uses
oxygen present which would otherwise be involved in the corrosion
process of the steel bars.”
The research team will assess the survival of different species of
bacteria in the concrete over time. They’ll allow the concrete to
mature over certain time periods and then grind it down to create a
suspension which can be assessed by biologists for surviving bacteria.