DEC 11

Researchers from the Fraunhofer Institute for Building Physics have developed a method to break down old concrete debris into its constituents for better recycling and re-use of the material. The process, called electrodynamic fragmentation, uses very short pulses (less than 500 nanoseconds) of induced lightning to separate gravel from cement materials in concrete.

Concrete is a material with a mixed environmental pedigree. Although its workability and durability make it extremely useful for a lot of purposes, it also has several drawbacks. There are the environmental impacts from the production of concrete, and it is also a major component of the materials going into landfills, so this makes the idea of recycling concrete a compelling one.

At present, most concrete recycling is merely to crush it and use it for sub-base under roads. This is better than landfilling it, but is a downcycling of the material. With the new lightning process, the aggregates can be more readily salvaged and re-used in new concrete.

Production of new cement from the recovered, separated material would be the ultimate goal of concrete recycling, since the production of cement is one of the single most intensive sources of CO2 emissions at present. While this process does not accomplish that, it does lay the way for that kind of recycling to become a possibility.

image: CC BY-SA 2.0 by brewbooks

via: Gizmag

Comments (4)

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Lightning on concrete blocks
written by Cathie of Reflective Tapes, December 12, 2012

Wow, that is so interesting about using a lightning like process to breakdown the cement. I didn't know that cement production produced so much Co2 but it's good we're one step closer to recycling it. This site is so interesting and informative too...I wish everyone would read it because then maybe people would stop arguing whether global warming was an issue and get to work fixing the problem.

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What is "downcycling"
written by pete, December 12, 2012

Do you invent words like "downcycling" due to a diminished vocabulary or is there some other reason for it?

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How much CO2 does this process generate
written by Kurt, December 24, 2012

The article mentions the use of lightning. I don't think it is really lightning, because it is too difficult to catch and store, so I suppose the term lightning is used simply to attract readers.

You would need immense power to fragment concrete, so where does the power come from if it doesn't come from lightning? I suppose it comes from the local power station. Is the power station coal fired or nuclear? If so, this process is probably doing very little for the environment.

Does the process generate nano-particles? I would guess that it does. Are the nano-particles properly filtered to prevent them from entering the atmosphere. Concrete nano-particles are particularly hazardous, on a par with lead/cadmium nano particles.

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...
written by Concrete Pumps, March 12, 2013

Concrete has dramatically changed our way of living. No doubt, Lighting prefers to travel through air or water, not solids. But scientists make a bolt of lightning pass through water and enter a solid. So workers can use concrete with lighting.

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