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”.

 
 
 
 

Podcast: SPQR

Rome celebrates its birthday in 2014. Image: Getty.

It’s just me this week, which is a problem, because there’s no one to stop me from indulging his sillier ideas. For example: an entire podcast about Ancient Rome.

Our guest is Kevin Feeney, a historian of the late Roman Empire based at Yale University, Connecticut. He gives us a whistlestop tour of Imperial Rome, with occasional side trips to other ancient cities. We also discuss other important matters such as the nature of Roman emergency services; whether the Emperor Claudius was all that Robert Graves made him out to be; why ancient Britain sucked; and, inevitably, why the whole enterprise fell apart.

Then we round off with the audience participation bit. This week we’re asking: which cities or places from history would you like to visit and why?

The episode itself is below. You can subscribe to the podcast on AcastiTunes, or RSS. Oh – and if you’d like to give us a nice review on iTunes, we’d really like that very much, thanks. Enjoy.

 

Skylines is supported by 100 Resilient Cities. Pioneered by the Rockefeller Foundation, 100RC is dedicated to helping cities around the world become more resilient to the physical, social and economic challenges that are a growing part of the 21st century.

You can find out more at its website.