Scientists have designed a “skin” that senses when concrete structures are damaged

Image: Bittbox via Flickr, reproduced under creative commons.

Concrete is pretty great, isn’t it? It’s strong, it’s cheap, it’s easy to use. Let’s hear it for concrete!

On the downside, though, it’s also prone to cracking – if there are swift changes in temperature, for example, or if it’s bearing too much weight. Cracks in concrete structure are annoying at the best of times, but if said structure is holding, say, nuclear waste, they can also be disastrous.

So a team of scientists from North Carolina State University and the University of Eastern Finland have developed plans for a “skin” that would flag up cracks or damage to the concrete’s surface. Their idea involves installing electrodes at the edges of a structure, then applying electrically conductive copper paint across the concrete. The electrodes would emit a constant, low-level current across the surface of the painted “skin”, monitored by a computer. If the surface was weakened, cracked or damaged, the paint would become less conductive, and the computer would sense a change in the signal. You can even analyse the data to produce a map of the damage.

Here’s a cracked piece of concrete, alongside a computer rendering of the damage:

Image: Aku Seppänen.

So far, the researchers have only tried the method out on small, 1m long pieces of concrete, but they’re hoping to test on bigger areas. Dr Mohammad Pour Ghaz, one of the paper’s co-authors, said the team were keen to show the method could work on “real-world structures”.


There's a new outdoor swimming pool art installation thing in London's King's Cross district

A swimmer tries out the new pond. Image: Getty.

At the dawn of a Bank Holiday Weekend, we feel a duty to keep our UK readers abreast of new outdoor city swimming pool developments. So to that end:

There's a brand new outdoor pool-cum-art installation on a stretch of landscaped earth behind London's King's Cross station. 

At first glance, it just looks like a standard outdoor pool, ringed with industrial red and white stripes and surrounded by the detritus of the area's massive regeneration project. 

But the pool is chemical free, filtered by underwater plant life, and its creators, from urbanist architecture firm Ooze, intend it to act as a comment on nature and the built environment. It's full title is actually "Of Soil and Water: the King's Cross Pond Club" and visitors are met with boards explaining the underwater plant filtration system. On the project's website, meanwhile, visitors are urged to "enter the water and participate in the installation as a piece of experiential art". Talk about immersive, eh? 

Here's the pool set in its context among building sites: 

And here are some excitable swimmers enjoying a first dip (note: jumping in is actually not allowed at this pool, so we're not sure what these jokers were playing at): 

And these members of the East German Ladies swimming team look absolutely delighted to be submerged at the intersection between art and nature:

Swimmers can book a specific time spot to visit the pool between 6am and dusk here. The pool opens today, and will be around for the next two years.