Rebar

Rebar is common steel reinforcing bar, an important component of reinforced concrete and reinforced masonry structures. It is usually formed from mild steel, and is given ridges for better frictional adhesion to the concrete.

Related Topics:
Reinforced concrete - Masonry - Mild steel - Friction

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Concrete is a material that is very strong in compression (pushing), but virtually without strength in tension (pulling). To compensate for this imbalance in concrete's behavior, rebar is formed into it to carry the tensile loads.

Related Topics:
Concrete - Compression - Tension - Load

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Masonry structures and the mortar holding them together have similar properties to concrete and also have a limited ability to carry tensile loads. Some standard masonry units like blocks and bricks are made with strategically placed voids to accommodate rebar, which is then secured in place with grout. This combination is known as reinforced masonry.

Related Topics:
Masonry - Mortar - Block - Brick - Grout

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While any material with sufficient tensile strength could conceivably be used to reinforce concrete, steel and concrete have similar coefficients of thermal expansion: a concrete structural member reinforced with steel will experience minimal stress as a result of differential expansions of the two interconnected materials caused by temperature changes.

Related Topics:
Coefficients of thermal expansion - Stress

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Although rebar has ridges that bind it mechanically to the concrete with friction, it can still be pulled out of the concrete under high stresses, an occurrence that often precedes a larger-scale collapse of the structure. To prevent such a failure, rebar is either deeply embedded into adjacent structural members, or bent and hooked at the ends to lock it around the concrete and other rebars. This first approach increases the friction locking the bar into place while the second makes use of the high compressive strength of concrete.

Related Topics:
Mechanically - Stress - Collapse - Structure

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Sometimes small plastic caps cover the tops of rebars as a safety measure during construction of a building, to prevent people from accidentally impaling themselves on the vertically standing rebars.

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