I'm Kevin Paine and i'm a professor of infrastructure materials in the BRE
centre for innovative construction materials here at the University of Bath
by background i'm a concrete technologist
which means that principally I'm looking
into ways in which to make concrete more sustainable.
My name is Susanne Gebhard i'm a senior lecturer in our Department of Biology
and Biochemistry and my day job is as a microbiologist so I work with bacteria
and broadly what my lab is interested in is how bacteria cope with stress and
stressful environments.
These are prefab, no this is in situ
that's includes what we want to work in the concrete is bacteria that are happy
with the limestone environment with the pH and the calcium.
about 50% of the UK's construction budget is spent
repairing materials that already exist and most of that is going to be concrete because
concrete is by far the most widely used construction materials.
The great advantage of self-healing concrete is
that the concrete is repairing itself in situ.
The way the technology works is
we make the concrete as normal but we've
added inside the concrete some capsules
containing bacteria once the concrete
cracks
the bacteria is released
into an environment where hopefully
the bacteria are happy.
When we grow the bacteria
in the lab we typically grow them on
things like this which is a petri dish
with some agar in there and has some
nutrients for the bacteria and if you do
this under the right conditions and if
we give the bacteria some calcium for
example, then the right bacteria can form
crystals out of the calcium we have a
crack in the concrete the bacteria can grow
in that crack and then because they make
that mineral that will eventually seal
that crack up with this lovely mineral
crystal layer on the surface of the
crack and
make it watertight which is what we want.
I've got a piece of self-healing
concrete here it was made probably,
I don't know, four or five years ago
it was cracked
and it was allowed to heal
and all that's left is a very tiny scar.
When we first had that very first
meeting about doing this project
yeah
and you guys wanted the bacteria to do
something and you went like oh i don't
know if this is possible and for me it
was like oh no this is really easy
bacteria are really good at this
yeah, I think the funniest thing is that
when I first started biologists called
bacteria bugs and so I copied them I
said oh we're putting the bugs into the
concrete they're like no no you can't
call them bugs, they're bacteria
and it was only after about three to four
years of doing this, Susanne said to me
Kevin, you're now allowed to call them bugs.
I think we can have even more fun by
actually using
the technology that we've developed that
goes inside the crack actually to maybe
even grow buildings
yeah or grow grow elements for buildings
themselves and do other things with the
technology and other materials that
maybe would work better,
yeah
if we put the bacteria in because
i mean we're talking about limestone
basically there's lots of use for that
other than concrete.
I think this is the most fun I've had
with research in a long time and it's
that like for me, because my background
is so molecular and all these little
details of what things inside bacterial
cells do and now we can have like little
bits of concrete that we can take places
and show to people and everybody
understands that there is a crack in a
concrete and a structure breaks and then
we can show them that it really works so
I find that,
that's been really fun to have
something really visual and to talk
to your friends and family about what
you do.