Corrosion-resistant rebar builds better bridges

Feb. 23, 2006
Civil engineers at Purdue University are developing a new generation of corrosion-resistant plastic bars reinforced with glass or carbon fibers that promises to double the time between expensive bridge repairs.

Robert Frosch, associate professor of civil engineering at Purdue, displays various types of reinforcing bars used in bridge construction. At top left are two segments of conventional steel rebar. The remaining samples are corrosionresistant plastic bars reinforced with glass or carbon fibers.


 

The concretestrengthening steel bars currently used in bridges are susceptible to corrosion, especially in the "deck," the uppermost portion of the bridge. Rebar embedded in bridgedeck concrete is exposed to deicing road salt that seeps through cracks in the pavement. Normally, bridge decks must be replaced every 20 or 30 years, but replacing rebar with bars made from fiber-reinforced polymers could extend the lifetime of a deck by as much as 50 to 100 years, says Robert Frosch, an associate professor of civil engineering.

As steel rebar corrodes, it makes the rebar expand, eventually causing chunks of concrete to break away from the bridge deck. This increases the exposure of underlying bridge components, which leads to more corrosion. The salty water also causes steel bars in both the upper and bottom portions of the deck to act as the negative and positive poles of a battery, increasing the rate of corrosion.

Replacing the steel rebar in the upper portion of the deck with fiber-reinforced polymer bars eliminates one of the poles and shuts down the battery effect, Frosch says.

Sponsored Recommendations

The entire spectrum of drive technology

June 5, 2024
Read exciting stories about all aspects of maxon drive technology in our magazine.

MONITORING RELAYS — TYPES AND APPLICATIONS

May 15, 2024
Production equipment is expensive and needs to be protected against input abnormalities such as voltage, current, frequency, and phase to stay online and in operation for the ...

Solenoid Valve Mechanics: Understanding Force Balance Equations

May 13, 2024
When evaluating a solenoid valve for a particular application, it is important to ensure that the valve can both remain in state and transition between its de-energized and fully...

Solenoid Valve Basics: What They Are, What They Do, and How They Work

May 13, 2024
A solenoid valve is an electromechanical device used to control the flow of a liquid or gas. It is comprised of two features: a solenoid and a valve. The solenoid is an electric...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!