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”.


A marketing agency is installing road signs for animals in Vilnius

The team install a hedgehog crosswalk. Image: Clinic 2012/Greta Gedminaitė photo.

Vilnius, capital of Lithuania, is home to around 550,000 people. It's also home to an unknown number of other creatures: birds, foxes, cats, dogs, and so on. 

This latter fact is what prompted a local ad agency, Clinic 2012, to install a number of unusual signs around the city. The miniature signs, decked out in the style of road signs, indicate such sites as a "crosswalk for hedgehogs", a "duck swimming pool" or a "rest area for cats". 

The agency has released very little information about the campaign beyond the following statement, explaining that the signs are there to remind passerby that animals share the city, too:

#TINYROADSIGN is a small project of the creative agency CLINIC 212 based in Vilnius, Lithuania. We have created it to show that we are not the only ones living in the city.

They have, however, released photos. And they are very, very cute. 

Here's an adorable (and remarkably well-trained) hedgehog crossing a path in Vingis park via the hedgehog crossing: 

Here are some cats, chilling out by what the agency calls a "cat rest area" sign: 

Ducks in the "duck swimming pool": 

Here are some pigeons, which in our personal opinion shouldn't be allowed in the same category as these other cute animals, but there you go:

Happy Friday, folks.

Image: Clinic 2012/Greta Gedminaitė photos.​