Reinforced concrete

Reinforced concrete (Ferro concrete) is plain concrete in which reinforcement in the form of rods, bars ("rebars") or fibers have been incorporated to strengthen the naturally brittle concrete. The use of reinforced concrete is a relatively recent invention, usually being considered as covering the last 150 years, and its accidental discovery is commonly ascribed to a Parisian gardener named Monier in about the year 1860. The vast majority of reinforcement is made of steel, but fiber-reinforced plastic materials are available.

Fiber-reinforced Concrete

Fiber-reinforcement is mainly used in Shotcrete, but can also be used in normal concrete. Fiber-reinforced normal concrete are mostly used for on-ground floors and pavements, but can be considered for a wide range of construction parts (beams, pilars, foundations etc) either alone or with hand-tied rebars.

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Fiber (steel or "plastic" fibers) reinforced concrete is less expensive than hand-tied rebar, while still increasing the tensile strength many times. Shape, dimmension and length of fibre is important. A thin and short fibre, for example short hair-shaped glass fiber, will only be effective the first hours after pouring the concrete (reduses cracking while the concrete is stiffening) but will not increase the concrete tensile strength. A normal size fibre for European Shotcrete (1 mm diameter, 45 mm length—steel or "plastic") will increase the concrete tensile strength.

Related Topics:
Steel - "plastic" fibers - Shotcrete

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Steel is the strongest commonly-available fiber, and come in different lengths (30 to 80 mm in Europe) and shapes (end-hooks). Steel fibres can only be used on surfaces that can tolerate or avoid corrosion and rust stains. In some cases, a steel-fiber surface is faced with other materials.

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Glass fiber is inexpensive and corrosion-proof, but not as strong as steel. Recently, spun basalt fiber, long available in Eastern Europe, has become available in the U.S. and western Europe. Basalt fibre is stronger and less expensive than glass, but historically, has not resisted the alkaline environment of portland cement well enough to be used as direct reinforcement. New materials use plastic binders to isolate the basalt fiber from the cement.

Related Topics:
Basalt fiber - Eastern Europe - Alkali

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The premium fibers are graphite reinforced plastic fibers, which are nearly as strong as steel, lighter-weight and corrosion-proof. Some experimeters have had promising early results with carbon nanotubes, but the material is still too expensive for most buildings.

Related Topics:
Graphite - Plastic fibers - Carbon nanotubes

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