Durability + Design

Building Performance and Aesthetics

A Product of Technology Publishing
JPCL/PaintSquare | D+D | Paint BidTracker

Subscribe to D+D Magazine
Download Free eBook on Polishing Concrete

Paint and Coatings Industry News

Main News Page


Recycling Concrete with Lightning Jolt

Wednesday, March 6, 2013

More items for Good Technical Practice

Comment | More

Scientists in Germany are summoning one of nature's most powerful forces to recycle man’s most widely used building material.

With the aid of lightning bolts, researchers at the Fraunhofer Institute for Building Physics' Concrete Technology Group in Holzkirchen, Germany, have developed a method to break down concrete into its components—cement and aggregate.

lightning strike

l∞senut / Flickr

Fraunhofer Institute’s Concrete Technology Group has developed a new concrete recycling method with help from lightning and some research from the 1940s.

This jolting method of recycling is much better than crushing it, according to the scientists' research announcement.

Addressing CO2 Issue

Concrete manufacturing accounts for eight to 15 percent of global carbon dioxide production, according to the researchers. One ton of burned cement clinker of limestone and clay releases 650 to 700 kilograms of CO2.

“And when it comes to recycling waste concrete, there is no ideal solution for closing the materials loop,” the team said. Germany alone generated 130 million tons of construction waste in 2010, the scientists note.

Although various groups are pursuing concrete recycling, the current processes produce huge amounts of dust; at best, the stone fragments end up as sub-base for roads, not building material, the German team said.

concrete recycling
© Fraunhofer IBP

The new method can break down concrete into its constituent parts.

“This is downcycling,” explains Volker Thome, a researcher from the institute.

To curb some of the harmful carbon emissions and efficiently reduce concrete into workable ingredients for new construction, the team revived a method that Russian scientists developed in the 1940s and “put it on ice,” they said.

Pulsed Lightning

The new process involves using “electrodynamic fragmentation”—very short pulses of induced lightning—to separate concrete into aggregate and cement materials.  

“Normally, lightning prefers to travel through air or water, not through solids,” said Thome. To ensure that the bolt strikes and penetrates the concrete, the experts used the Russian scientists’ expertise.

water

Malene Thyssen / Wikimedia Commons

Lightning prefers to travel through water rather than a solid.

More than 70 years ago, they discovered that dieletric strength (the resistance of every fluid or solid to an electrical impulse) is not a physical constant, but changes with the duration of the lightning, the scientists said.

“With an extremely short flash of lightning—less than 500 nanoseconds—water suddenly attains a greater dielectric strength than most solids,” explains Thome.

'A Small Explosion'

Fraunhofer researchers learned that when concrete immersed in water is hit with a 150-nanosecond bolt of lightning, the discharge runs through the concrete and weakens it.

“In the concrete, the lightning then runs along the path of least resistance, which is the boundaries between the components, i.e. between the gravel and the cement stone,” the researchers said.

Explained Thome: “The pre-discharge which reaches the counter-electrode in our fragmentation plant at first, then causes an electrical breakdown.

“At this instant, a plasma channel is formed in the concrete, which grows within a thousandth of a second, like a pressure wave from the inside outwards. The force of this pressure wave is comparable with a small explosion.”

Currently, the laboratory fragmentation plant can process one ton of concrete waste per hour. Thome said the researchers have a goal of at least 20 tons per hour, which could be market-ready in less than two years.

   

Tagged categories: Concrete; Construction; Recycled building materials; Research

Comment from Steve Black, (3/6/2013, 2:27 PM)

I guess it depends on where the power is coming from if this is a sustainable process. I get the recycling aspect but if you burn a bunch of fossil fuel to break the concrete back down then it only adds to the carbon foot print of the material.


Comment Join the Conversation:

Sign in to our community to add your comments.

Arroworthy
ArroWorthy's Handcrafted Professional Brushes

One Dip of paint with our handcrafted semi-oval Rembrandt brush, you'll see why ArroWorthy makes a professional brush of unrivaled quality and performance.


KTA-Tator, Inc. - Corporate Office
KTA Inspection Instruments

Eliminate Application Uncertainties:
• Moisture Content
• Ambient Conditions
• Surface Preparation
• Coating Thickness
Call 1-800-KTA-GAGE
(800-582-4243)


Shield Industries, Inc
FireGuard® E-84 Intumescent Coating - Shield Industries, Inc

Trust the certified protection of the industry’s most innovative intumescent coating FireGuard® E-84 to provide you with the 1 and 2 hour fire ratings you need.


Dumond Chemicals Inc.
LEAD STOP®
Lead Encapsulating Compound

is a thick elastomeric coating that is made to be a long lasting barrier over lead-based paint. LEAD STOP® provides a protective barrier coat that seals and locks in lead that is contained in old lead-based paints on previously painted surfaces.


SSPC: The Society for Protective Coatings
http://www.sspc.org/

Join SSPC and Enhance
Your Career !


PPG  Architectural Coatings / Porter Paints / PGH Paints
Property Maintenance Solutions

Glidden Professional at The Home Depot® provides property managers with professional paint recommendations, project planning and FREE jobsite delivery.


Chemique Inc.
Paint Removal Made Easy!

Remove multiple coats in one application. Easy to use and safe. All products meet or exceed V.O.C. regulations. Contain no methylene chloride, methanol or petroleum distillates.

 
 
 
Technology Publishing

The Technology Publishing Network

The Journal of Protective Coatings & Linings (JPCL) PaintSquare
Durability + Design Paint BidTracker JPCL Europe

 
EXPLORE D+D:      Interact   |   Blogs   |   Resources   |   Buying Guides   |   Webinars   |   White Papers   |   Classifieds
GET D+D:      Subscribe   |   Advertising Media Kit
KNOW D+D:      About D+D   |   Privacy policy   |   Terms & conditions   |   Site Map   |   Search   |   Contact Us
 

© Copyright 2010-2014, Technology Publishing, Co., All rights reserved
2100 Wharton Street, Suite 310, Pittsburgh PA 15203-1951; Tel 1-412-431-8300; Fax 1-412-431-5428; E-mail webmaster@paintsquare.com