PaintSquare.com


The First Word in Protective & Marine Coatings

A Product of Technology Publishing / PaintSquare
JPCL | PaintSquare News | Durability + Design | Paint BidTracker

Paint and Coatings Industry News

Main News Page


Concrete Reuse Gets Bolt from the Blue

Thursday, March 7, 2013

More items for Coating Materials

Comment | More

A flash of inspiration has led researchers to a remarkable new lightning-laced advance in recycling concrete.

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 zap 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.

Reducing CO2

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 Join the Conversation:

Sign in to our community to add your comments.

Mitsubishi Gas Chemical America
Performance Amine 1,3-BAC

A highly reactive cycloaliphatic diamine offering superior performance. Reasonable cost and curing efficacy makes it suitable for all types of epoxy resin applications.


Polyval Coatings
POLYFLEX brand Polyurea

high chemical resistant membranes are used extensively to protect our environment in secondary containment applications.


International Paint LLC

International Paint Engineered Coatings

Learn about our solutions for:
  • Structural Steel
  • Piping & Equipment
  • Storage Tanks
  • Pressure Vessels
  • Secondary Containment


    BASF
    New resins from BASF will have metals loving water:

    Excellent corrosion resistance, low VOC, high gloss, thin films basf.us/industrialcoatings
    polyorders@basf.com
    800-231-7868


    Safety Lamp of Houston, Inc.
    Wet & hazardous area lighting solutions from SAFETY LAMP of Houston

    New WOLF LED and fluorescent lights are now available, including low voltage tank lighting kits.
    Call: (281) 964-1019.


    Wasser High-Tech Coatings Inc.
    Wasser Coatings Protect

    some of the most important bridges in the country; learn about our NEPCOAT-approved system and our entire range of MCU & Polyurea coatings. 1-800-627-2968 www.wassercoatings.com


    Simpson Strong-Tie
    Repair, Protect & Strengthen

    Need a coating? Turn to Fox. We have solutions to repair, protect and strengthen concrete, steel and wood substrates. Call 888-760-0369 or email info@foxind.com

  •  
     
     
    Technology Publishing

    The Technology Publishing Network

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

     
    EXPLORE:      JPCL   |   PaintSquare News   |   Interact   |   Buying Guides   |   Webinars   |   Resources   |   Classifieds
    REGISTER AND SUBSCRIBE:      Free PaintSquare Registration   |   Subscribe to JPCL   |   Subscribe to PaintSquare News
    MORE:      About PaintSquare.com   |   Privacy policy   |   Terms & conditions   |   Site Map   |   Search   |   Contact Us
     

    © Copyright 2000-2014, Technology Publishing / PaintSquare, 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