PaintSquare.com
Follow us on Twitter Follow us on LinkedIn Like us on Facebook Follow us on Instagram Visit the TPC Store
Search the site

 

Advertisement

PaintSquare


Coatings Industry News

Main News Page


Concrete Tells What Lies Beneath

Monday, February 24, 2014

More items for Quality Control

Comment | More

Some cracks in concrete have been known to heal themselves, but they couldn’t report back on when they did or how the whole operation went.

Now, ultrasound technology may change that.

GT-CEE researchers
Photos unless indicated: Georgia Tech CEE

The research team included (from left) Gun Kim, Katie Matlafk and Chiwon In.

Researchers at Georgia Tech's School of Civil and Environmental Engineering have developed a way to use ultrasonic technology to monitor and measure self-healing of sub-surface concrete cracks in damp and aqueous environments.

Microscopic Self-Healing

Monitoring and evaluation of self-healing in concrete using diffuse ultrasound," a peer-reviewed paper published in Nondestructive Testing and Evlaution (NDT&E) International, explains how ultrasound can measure the progression of autogenous healing (self-healing) below the surface. (The paper was also re-published in a special virtual issue of the journal.)

"Self-healing is an inherent process of concrete crack repair that occurs when there is both moisture present and tensile stress absent from an environment, such as in a marine setting," Georgia Tech reports in a research announcement.

Concrete Piers
Courtesy Flickr user portoftacoma via Georgia Tech CEE

Cracks in concrete may self-heal in marine environments where moisture is present and tensile stress is absent.

"At a microscopic level, self-healing happens due to a combination of mechanical blocking by particles carried into a crack, along with the filling of the crack by calcium carbonate deposits, derived from hydration products within the concrete itself."

This natural process can aid in closing relatively narrow dormant cracks.

But inspectors and maintenance directors would find it more helpful if they knew when it was occurring.

How They Tested

The research was a collaboration by former graduate students Chiwon In and R. Brett Holland (both Ph.D.); professors Kimberly E. Kurtis, Lawrence F. Kahn and Laurence J. Jacobs (all Ph.D.); and civil engineering Senior Research Engineer Jin-Yeon Kim, Ph.D.

Measuring cracks before exposure

Graduate students take crack width measurements before sealing and exposure.

The team performed measurements on cracked and un-cracked concrete specimens of three different mix designs, then exposed the specimens to a simulated marine environment for four months.

Then, the team measured again using two diffuse ultrasonic parameters: their own novel application of the effective diffusivity, as well as an Arrival Time of Maximum Energy (ATME) measure.

What They Found

As self-healing progressed, the ATME of both tensile and flexure cracked specimens decreased, while the diffusivity increased, the university said. The team also recovered the initial values found in the un-cracked control specimens after self-healing.

This suggested not only self-healing of the cracks, but that the researchers' new method predicted self-healing trends more effectively than the ATME method.

The researchers concluded that their method was capable of monitoring and evaluating the self-healing of concrete more reliably than ATME values, which depend on where on the crack face self-healing occurs.
 

   

Tagged categories: Concrete defects; Concrete repair; Cracks; Maintenance programs; Quality control; Research

Comment Join the Conversation:

Sign in to our community to add your comments.

Advertisements
 
DeFelsko Corporation
 
PosiTector SHD Shore Hardness Durometer
 
PosiTector SHD measures the hardness of non-metallic materials. Features a measurement timer, auto ignore mode and internal memory. Shore A or D available.
 

 
Fischer Technology Inc.
 
MP0R with rotating display screen
 
Automatic rotating display screen just like your smart phone. Click for Video
Call 800-243-8417
 

 
SAFE Systems, Inc.
 
Portable Blast &
Recovery Equipment
 
Trailer or skid mounted blast and recovery equipment. Systems designed for maximum versatility, environmental compliance
and overall cost savings.
Call 1-800-634-7278
 

 
Industrial Vacuum Equipment Corp.
 
Hurricane Vacuums
& Dust Collectors
 
Vacuum and dust collector hose, filters and related accessories.
IndustrialVacuum.com
 

 
PPG Protective and Marine Coatings Group
 
We Protect and Beautify the World
 
PPG is widely recognized as a world leader in protective and marine coatings, developing innovative, cutting-edge products and services.
 

 
HoldTight Solutions Inc.
 
NO FLASH RUST - NO CONTAMINANTS
 
Our HoldTight®102 salt remover & flash rust
preventer prevents flash
rust by removing surface contaminants. Contact us
for your nearest distributor.
(800) 319.8802 sales@holdtight.com
 

 
KTA-Tator, Inc. - Corporate Office
 
KTA Online
Instrument Catalog
 
• Any Manufacturer
• Any Instrument
• Any Time
Visit www.ktagage.com
Or call 800-582-4243
 

 
SEMicro Division, M.E. Taylor Engineering, Inc.
 
Coatings Adhesion Testers
 
The PATTI® accurately measures the bond strength between coating & substrate. Outfitted properly, the surface can be rough, porous, or curved & >10K psi strong!
 

 
Absolute Equipment/Grand Rental Station
 
TIER 4 EQUIPMENT
 
We have Tier 4 Equipment including Air Compressors & Generators for Sale & Rent! Your job may now require Tier-4. www.absoluteequip.com or Call 412-931-6655.
 

 
SSPC: The Society for Protective Coatings
 
http://www.sspc.org/
 
Join SSPC and Enhance
Your Career !
 

 
 
 

Technology Publishing Co., 2100 Wharton Street, Suite 310, Pittsburgh PA 15203-1951

TEL 1-412-431-8300  • FAX  1-412-431-5428  •  EMAIL webmaster@paintsquare.com


The Technology Publishing Network

Durability + Design PaintSquare the Journal of Protective Coatings & Linings Paint BidTracker

 
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