Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

U.S. oils can protect concrete bridge tendons during construction delays

29.04.2004


A Penn State study has shown that there are U.S. oils that can match or exceed the characteristics of the European leader for temporary corrosion protection of concrete bridge tendons.


An undamaged tendon (left) a tendon subjected to the salt solution test and the test tube.
Photo Credit: Greg Grieco, Penn State



Dr. Andrea Schokker, the Henderson professor of civil engineering, who led the project, says, "The North American post-tensioning industry was considering importing the European product, possibly at higher cost than the oils available in the U.S. market. Our study established that there are adequate products available in North America to do the job."

The study is detailed in the current issue of the Post-Tensioning Institute Journal in a paper, "Bond and Corrosion Studies of Emulsifiable Oils Used for Corrosion Protection in Post-Tensioned Tendons." The authors are Edwin Salcedo-Rueda, a Penn State doctoral candidate in civil engineering; Schokker: Dr. John E. Breen, who holds the Nasser I. Al-Rashid chair in civil engineering at the University of Texas at Austin; and Dr. Michael E. Kreger, professor of civil engineering at Purdue University.


In post-tensioned construction, tendons made of seven twisted steel wires, are inserted into ducts that run the length of pre-cast concrete segments. The tendons are then stretched to put them under tension and anchored at the ends to hold the concrete segments in place. The ducts are eventually filled with portland cement grout which not only protects the steel tendons from corrosion but also distributes the bond with the tendon along its full length. When grouting delays occur, oil may be applied to the steel tendon to prevent corrosion during the unprotected period.

Schokker and her research team tested 19 anti-corrosion oils, 18 North American products and the European leader. The oils were subjected to three environmental tests and one mechanical test. The goal was to find oils that produce the least detrimental effects on the bond between the tendon and grout in addition to good corrosion inhibiting properties.

The environmental tests, which lasted six months, included exposing oil-coated tendons outdoors including an extreme Pennsylvania winter typical of the northern U.S.; laboratory exposure to 73 degrees F with 95 percent humidity comparable to some southern states and contact in sealed tubes with a diluted (five percent) salt solution, semi-controlled temperatures and variable relative humidity similar to saltwater coastal areas.

In the mechanical tests, the research group used a modified standard test to measure the force necessary to pull the tendon out of the grout.

The team found that six of the 18 domestic oils provided adequate corrosion protection in all three test environments. The top products from both the environment and mechanical tests were Citgo Cutting Oil NC 205, Shell/Texaco Dromus ABD and Shore Chemical Emul. Cutting Oil. These products have been recommended for Phase II testing at the University of Texas at Austin in large scale post-tensioned beams to examine bond and ultimate flexural capacity of structural members.

The study was supported by the Texas Department of Transportation and the Federal Highway Administration.

Barbara Hale | EurekAlert!
Further information:
http://www.psu.edu/

More articles from Process Engineering:

nachricht Etching Microstructures with Lasers
25.10.2016 | Fraunhofer-Institut für Lasertechnik ILT

nachricht Applying electron beams to 3-D objects
23.09.2016 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>