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Lightning used to recycle concrete rubble

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October 8, 2012

A new method can recycle concrete with greater efficiency by zapping it with lightning (Im...

A new method can recycle concrete with greater efficiency by zapping it with lightning (Images: Shutterstock [1] [2])

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You probably didn't wake up this morning pondering concrete. But look around and chances are, you'll see the substance in abundance. Buildings, walls, bridges, parking garages … you could write a (not very interesting) book on all the places you see concrete.

The mixture of cement, aggregate, and water has a longevity that's the stuff of legend; just look at the Roman Pantheon. But roads get replaced, old buildings get demolished, and, every year, we're left with mountains of concrete rubble. In 2010, Germany alone produced an estimated 130 million tons (117.9 million tonnes) of construction waste.

Further complicating matters is the impact on the environment. With cement production as the primary culprit, concrete manufacturing contributes an estimated 8 to 15 percent of global CO2 production. Concrete recycling is limited, with the present shredding method producing enormous amounts of dust, and only utilizing downgraded leftovers.

Lightning

It may not reanimate the dead, but this method can repurpose old building materials (Backg...
It may not reanimate the dead, but this method can repurpose old building materials (Background: Shutterstock)

Enter researchers from the Concrete Technology Group in Holzkirchen, Germany, who have found a solution that would make Dr. Frankenstein proud. Their new approach can recycle concrete with unprecedented efficiency. Their secret: zap it with lightning.

Lightning prefers to travel through air or water, not solids (apart from Doc Brown's clock tower). But these German researchers remembered a 70-year-old study, which showed that an extremely short duration (less than 500 nanoseconds) makes a bolt of lightning more likely to pass through water and enter a solid.

That's great, but why care about lightning striking a pile of concrete? When the electricity strikes the rubble, lightning travels along the path of least resistance: the barriers between the gravel and cement stone. This tears the concrete apart, separating it into its fundamental components – ripe for maximum recycling.

Fortunately, this isn't just theory. The Holzkirchen researchers can already zap lab-produced lightning into concrete at a rate of one ton (.9 tonnes) per hour. They project that a rate of 20 tons (18 tonnes) per hour would achieve optimal efficiency. Such a concrete recycling plant could be ready to go within two years.

If this project proves fruitful, we could eventually see dramatic improvement in worldwide concrete recycling. That would mean less new cement manufacturing, and a (theoretical) drop in global CO2 emissions. For more detailed information on this new process and the research team behind it, you can hit up the source link below.

Source: Fraunhofer

About the Author
Will Shanklin Will Shanklin is Gizmag's Mobile Tech Editor, and has been part of the team since 2012. Will has a Master's degree from U.C. Irvine and a Bachelor's from West Virginia University. He currently lives in New Mexico with his wife, Jessica.
  All articles by Will Shanklin
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8 Comments

Key question would be how much energy does it take to recycle vs manufacture new cement. Interesting concept though! Thinking outside the box using 70 year old studies and "lightening"! Interesting stuff.

KAJO
8th October, 2012 @ 05:51 pm PDT

I often see piles of concrete pulled from highways that is still in great shape. These are nearly a foot thick, and usually still in rectangular shape. I've wondered about the feasibility to cut these into smaller blocks to build patios and driveways.

sunfly
8th October, 2012 @ 07:40 pm PDT

I once met the director of the Fraunhofer Institute in Cambridge, Mass. (yes, they're branched out to the US, with an all American staff).

He told me that while the German "Max Planck Institutes" turn money into research, the Fraunhofer Institutes are designed to turn research into money! AKA real world applications such as this one.

moreover
9th October, 2012 @ 10:35 am PDT

So does this give building demolishers a new method to bring down concrete buildings or (hopefully not) terrorists and secret government agencies a new weapon to damage concrete buildings?

Lloyd D'Rose
9th October, 2012 @ 01:37 pm PDT

Downside: every electrical discharge also creates blasts of ozone. Need I say more?

Upside: in the USA there are some states that encounter hundreds of lightning storms annually. Build frankenstinian towers to gather and direct lightning strikes into piles of concrete. Free energy.

IGOR I need more power !

grtbluyonder
9th October, 2012 @ 06:50 pm PDT

RE:

"Lightning prefers to travel through air or water, not solids (apart from Doc Brown's clock tower). But these German researchers remembered a 70-year-old study, which showed that an extremely short duration (less than 500 nanoseconds) makes a bolt of lightning more likely to pass through water and enter a solid." A very small & confused effort to make something comprehensible to us mere mortals, reads like a pitifull muddle. reading the "Source: Fraunhofer" link in the article is a little clearer. My big problems with the quoted material "Lightning prefers to travel through air or water, not solids" Lightning is a flow of electricity that behaves the same as any other high voltage electrical charge. Lightning has no more preference for anything any more than a rock has a preference for anything. Copper ( also most metals) is a solid and it conducts electricity (including lightning) far better than air or water

Dave B13
10th October, 2012 @ 06:48 am PDT

With buildings such as the t30 tower going up in china in 15 days our dependence on concrete is coming to an end. The idea of a bio liquid to engulf actual buildings seems to be a much better quest then the lighting. There would be no need to break up a building only then to transport it to a place far away to only then re break it up again,On site complete demolition is a far more efiant prospect to achieve. Pyrotechnic but perfectly confined to a selected area. Granted that such a bio soup which defeats the substances of concrete would be an amazing development and difficult the most likely scenario is that we will simply use lasers to vaporizer anything we wish when we wish it.Thus eliminating both ideas and the need of investment in those Fields. Gentlemen

Richardf
10th October, 2012 @ 03:28 pm PDT

To pursue any form of idiotic research in this case the knowing and ability to vaporizer a building is a typical thing these days.The slow evolution of lighting to chemicals to the final weapon lasers should be avoided

Concentrating on a 50 megadul laser beam is the end result and can be built within years ,its much more fun to zap stuff as well ,A truck can currently carry 2 layers of material required to make a snap tougher building ,the transport in this case is then turned into a on site destruction facility .saving more money.

Richardf
11th October, 2012 @ 10:48 am PDT
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