As it has been explained concrete gets its tensile mainly from its reinforcements and reinforcements do get decomposed by the exposure to the atmosphere . Examples of such exposure include marine areas, regions where road salts are used for deicing, and locations where salt contaminated aggregates are used in the concrete mixture. When properly protected from ion attack, steel reinforcement can last for decades without exhibiting any visible signs of deterioration. However, it is not always possible to provide this kind of corrosion protection. Insufficient concrete cover, poor design or workmanship, poor concrete mix, and presence of large amounts of aggressive agents all can lead to corrosion of the steel rebar and cracking of the concrete. Rusting of concrete is the biggest problem after all so  Fiber reinforced polymer (FRP)  composite rebar have the potential to address this corrosion problem with the steel reinforcements. subjected to flexure, shear, and compression loadings.  FRP Composite rebar are totally resistant to chloride ion attack, offer a tensile strength of 1½ - 2 times that of steel, weigh only 25% of the weight of equivalent size steel rebar, and are highly effective electromagnetic and thermal insulators.

Applications:

Four general categories of applications where FRP rebars are suitable alternatives to steel, epoxy-coated steel, and stainless steel bars:

Reinforced Concrete Exposed to Deicing Salts

FRP bars can eliminate the corrosion problems and reduce maintenance and repair costs in northern climates where massive quantities of deicing salts are used every year on roads and pavements.  Applications include: parking structures; bridge decks; Jersey barriers, parapets; curbs; retaining walls and foundations; roads and slabs on grade; and many others.

Structures Built in or Close to Seawater

Corrosion of steel reinforcement is a common problem in structures built in or near seawater.  Possible applications are: quays; retaining wall; piers; jetties; caissons; decks; piles; bulkheads; floating structures; canals; roads and buildings; offshore platforms; swimming pools and aquariums; and others.

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Applications Subjected to Other Corrosive Agents

Chemical processing industries as well as domestic or industrial wastewaters constitute major sources of corrosion for steel reinforcement.  Typical applications include: wastewater treatment plants; petrochemical plants; pulp and paper mill and liquid gas plants; pipelines and tanks for fossil fuel; cooling towers; chimneys; mining operations of various types, nuclear power plants; and nuclear dump facilities.

Applications Requiring Low Electric Conductivity or Electromagnetic Neutrality

Using steel bars in applications where low electric conductivity or electromagnetic neutrality is needed often result in a complex construction layout, if such use is possible at all. Possible applications are: aluminum and copper smelting plants; manholes for electrical and telephone communication equipment; structures supporting electronic equipment such as transmission towers for telecommunications; airport control towers; magnetic resonance imaging in hospitals; railroad crossing sites, and military structures with requirement for radar invisibility.

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