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”.


While Londoners whine about gentrification, other cities long for it

The as-yet-ungentrified Little Maltings. Image: Niall Crowley.

A canal cuts through an urban landscape. It’s overlooked by angular facade of a Grade II listed Victorian brewery. It’s been sympathetically converted into loft apartments, live-work spaces and artist studios.

The canal bustles with life. Boats, barges, a floating bookshop, even a floating cocktail bar. Strollers, joggers, cyclists, dog-walkers and meanderers all negotiate their way along the narrow towpath. A strip of independent shops, cafes, bars and a theatre look out onto the park from the west. It’s a short 10 minute walk from the railway station; there’s even a canalside pub – The Bridge – with its own microbrewery.

It’s an urban success story. Or at least it would be, if it was London. The place I describe is Langley Green, a small village-like corner of the Black Country, a few miles north of Birmingham where I grew up. The theatre, the pub with the craft beers, the canal, the Grade II Victorian brewery are all there.

Or at least they were. 

Langley Maltings, was never transformed into loft apartments, as developers once promised. It’s now a burnt-out ruin, having twice been attacked by arsonists. The once-popular pub with the micro brewery closed its doors a couple of years ago, and has since been demolished. Only a part of the front elevation remains.

The only life the canal sees is the occasional dog-walker, and the high street, like many around the country, is in steady decline. The theatre and the cobblers (run by a father and son since the 50s or 60s) are thankfully, still there. 

It’s a world away from my adopted home of East London, where much-maligned hipsters and creatives have helped transform rundown areas where, not so long ago, few people wanted to live. The Regents Canal, on the edge of my estate, does bustle with life. Here, you can browse second-hand books and buy cocktails on canal barges. And the canal-side cafe does sell porridge for around £4 a bowl, though don’t tell that to Class War. 

Nearby Shoreditch Park, which borders “gentrified” Hoxton and Old Street, is well used and loved by locals, who come to meet up, read, hang out, picnic and play. Overlooking the park is not a Victorian brewery but the old Gainsborough film studios, now a gated apartment complex (which also overlooks the canal), where a one-bedroom flat will cost upwards of £500,000 and one of the newly-built townhouses on the other corner of the park start at £3m.

Many years ago I spent a weekend on the estate where I now live, visiting friends who were squatting in a tower-block. It was, and still is, a sprawling, ugly 1970s estate in a then unfashionable area.

Back then many of the flats lay empty, which is why the local authority eventually allowed squatters, including my friends, to take up legal residency. Now it seems everybody wants to live here. In gentrified east London, even this dreary old estate is now de rigueur.

Only there would you  find, say, a young Japanese fashion student living next door to a born-and-bred London postman; hear the sound of  a violin rehearsal waft in through an open window, while your neighbour’s hip hop tunes vibrate through the walls.

Here, the kid spraying graffiti all over the lift works for the props department of the production company filming on the estate, and the stage play showing at the local ‘community centre’ is sponsored by the Royal Court and stars two Oscar-winning actors. Here, there’s always somewhere new to go, something new to do. You can eat, drink or dance most times of the day or night, any day of the week. 

Still, some people complain about hipsters, “greedy” developers, social cleansing and about gentrification. When I returned to live in Dalston a few years ago, after a period away from London, I was stunned by how much the place had changed and by how vastly improved it was. “Wow! Hasn’t Dalston changed?” I said, in wonder to a member of staff at the trendy new Curve Garden.

I was equally stunned by his negative take. “It’s not all that bad.” he groaned. Maybe people have short memories? Or maybe those doing the complaining were in fact the previous generation of gentrifiers who now want to lift the drawbridge on the rest of us?

In Langley Green, where I happened to be when anti-gentrification protesters attacked the Cereal Killer cafe in Shoreditch, people don’t complain about hipsters, gentrification or rising house prices. And they definitely don’t complain about overpriced cereal bars.

But I wish they did. If moustachioed  hipsters and creatives were opening oddball coffee shops and floating cocktail bars; if developers were breathing new life into old Victorian breweries, then I suspect people in Langley, and other rundown parts of the country would welcome them as a sign of some much-needed economic dynamism.

For what underpins the revival of former undesirable areas of London is the city’s relative economic success over recent years. Now the rest of the country needs an economic revival. And that won’t happen without massive investment in new industrial sectors and large-scale infrastructure projects.

When that happens, maybe people in the rest of the country will have the luxury of complaining about their high streets being filled with art galleries, brasseries and overpriced cereal cafes. 

Niall Crowley is a writer, designer and former bar-owner based in London. He is speaking at “Gentrify this! The pros and cons of urban development” at the Battle of Ideas festival on 18 October at the Barbican.

CityMetric is a media partner for the festival.