A rebar (short for reinforcing bar), also known as reinforcing steel, reinforcement steel, or a deformed bar, is a common steel Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten. Carbon and other elements act as a hardening agent, preventing bar, and is commonly used in reinforced concrete Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. The term Ferro Concrete refers only to concrete that is reinforced with iron or steel. Other materials used to reinforce concrete can be organic and inorganic fibres as well as composites and reinforced masonry Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone such as marble, granite, travertine, limestone; concrete block, glass block, and tile. Masonry is generally a highly durable form of structures. It is usually formed from carbon steel Carbon steel, also called plain carbon steel, is steel where the main alloying constituent is carbon. The American Iron and Steel Institute defines carbon steel as: "Steel is considered to be carbon steel when no minimum content is specified or required for chromium, cobalt, columbium, molybdenum, nickel, titanium, tungsten, vanadium or, and is given ridges for better mechanical anchoring into the concrete. In Australia For at least 40,000 years before European settlement in the late 18th century, Australia was inhabited by indigenous Australians, who belonged to one or more of the roughly 250 language groups. After sporadic visits by fishermen from the immediate north and discovery by Dutch explorers in 1606, Australia's eastern half was claimed by Britain in 177, it is colloquially A colloquialism is a linguistic phrase that is characteristic of or only appropriate for casual, ordinary, familiar, and/or informal written or spoken conversation, rather than for formal speech, standard writing, or paralinguistics. Dictionaries often display colloquial words and phrases with the abbreviation colloq. as an identifier known as reo.
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History
Rebars inside the Leaning Tower of Nevyansk.Rebars were known in construction well before the era of the modern reinforced concrete Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. The term Ferro Concrete refers only to concrete that is reinforced with iron or steel. Other materials used to reinforce concrete can be organic and inorganic fibres as well as composites. Some 150 years before its invention rebars were used to form the carcass of the Leaning Tower of Nevyansk in Russia Russia (pronounced /ˈrʌʃə/ ; Russian: Россия, tr. Rossiya, pronounced [rɐˈsʲijə] ( listen)), also officially known as the Russian Federation (Russian: Российская Федерация, pronounced [rɐˈsʲijskəjə fʲɪdʲɪˈraʦəjə] ( listen)), is a state in northern Eurasia. It is a federal semi-presidential republic,, built on the orders of the industrialist A business magnate, sometimes referred to as a czar, mogul, tycoon, baron, oligarch, or industrialist, is an informal term used to refer to a person who has reached a prominent place in a particular industry and whose wealth has been derived primarily therefrom Akinfiy Demidov. The purpose of such construction is one of the many mysteries of the tower. The cast iron Cast iron usually refers to grey iron, but also identifies a large group of ferrous alloys, which solidify with a eutectic. The colour of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due to its carbide impurities which allow cracks to pass straight through. Grey cast iron is used for rebars was of very high quality, and there is no corrosion Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen. Formation of an oxide of iron due to oxidation of the iron atoms in solid solution is a on them up to this day. The carcass of the tower was connected to its cast iron tented roof, crowned with what might have been the first lightning rod A lightning rod or lightning conductor (UK) is a metal rod or conductor mounted on top of a building and electrically connected to the ground through a wire, to protect the building in the event of lightning. If lightning strikes the building it will preferentially strike the rod, and be conducted harmlessly to ground through the wire, instead of in the Western world. This lightning rod was grounded In electrical engineering, ground or earth may be the reference point in an electrical circuit from which other voltages are measured, or a common return path for electric current, or a direct physical connection to the Earth through the carcass, though it is not clear whether the effect was intentional.[1]
Use in concrete and masonry
Concrete Concrete is a construction material composed of cement and other cementitious materials such as fly ash and slag cement, aggregate (generally a coarse aggregate made of gravels or crushed rocks such as limestone, or granite, plus a fine aggregate such as sand), water, and chemical admixtures is a material that is very strong in compression Physical compression is the result of the subjection of a material to compressive stress, resulting in reduction of volume. The opposite of compression is tension. In simpler words, Compression is a pushing force, but relatively weak in tension In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. It is the opposite of compression. As tension is the magnitude of a force, it is measured in newtons and is always measured parallel to the string on which it applies. There are two basic possibilities for systems of. To compensate for this imbalance in concrete's behavior, rebar is cast into it to carry the tensile loads In structural design, assumed loads are specified in national and local design codes for types of structures, geographic locations, and usage. In addition to the load magnitude, its frequency of occurrence, distribution, and nature are important factors in design. Loads cause stresses, deformations and displacements in structures. Assessment of.
Masonry structures and the mortar Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. The blocks may be stone, brick, cinder blocks, etc. Mortar becomes hard when it sets, resulting in a rigid aggregate structure. Modern mortars are typically made from a mixture of sand, a binder such as cement or lime, and water. Mortar can also be 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 A brick is a block of ceramic material used in masonry construction, usually laid using various kinds of mortar are made with strategically placed voids to accommodate rebar, which is then secured in place with grout Grout is a construction material used to embed rebars in masonry walls, connect sections of pre-cast concrete, fill voids, and seal joints . Grout is generally composed of a mixture of water, cement, sand, often color tint, and sometimes fine gravel (if it is being used to fill the cores of cement blocks). It is applied as a thick liquid and. This combination is known as reinforced masonry.
While any material with sufficient tensile strength could conceivably be used to reinforce concrete, steel and concrete have similar coefficients of thermal expansion All materials change their size when subjected to a temperature change as long as the pressure is held constant. In the special case of solid materials, the pressure does not appreciably affect the size of an object, and so for solids, it usually not necessary to specify that the pressure be held constant. The coefficient of thermal expansion: a concrete structural member reinforced with steel will experience minimal stress In continuum mechanics, stress is a measure of the average force per unit area of a surface within a deformable body on which internal forces act. In other words, it is a measure of the intensity of the internal forces acting between particles of a deformable body across imaginary internal surfaces . These internal forces are produced between the as a result of differential expansions of the two interconnected materials caused by temperature changes.
Physical characteristics
Steel has an expansion coefficient nearly equal to that of modern concrete. If this were not so, it would cause problems through additional longitudinal and perpendicular stresses at temperatures different than the temperature of the setting.[2] Although rebar has ribs that bind it mechanically to the concrete, 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 (40-60 times the diameter), or bent and hooked at the ends to lock it around the concrete and other rebar. This first approach increases the friction locking the bar into place, while the second makes use of the high compressive strength of concrete.
Common rebar is made of unfinished tempered steel, making it susceptible to rusting Rust is a general term for a series of iron oxides. Colloquially, the term is applied to red oxides, formed by the reaction of iron and oxygen in the presence of water or air moisture. Yet, there are also other forms of rust, such as the result of the reaction of iron and chlorine in an environment deprived of oxygen, such as rebar used in. Normally the concrete cover is able to provide a pH value higher than 12 avoiding the corrosion reaction. Too little concrete cover can compromise this guard through carbonation from the surface. Too much concrete cover can cause bigger crack widths which also compromises the local guard. As rust takes up greater volume than the steel from which it was formed, it causes severe internal pressure on the surrounding concrete, leading to cracking, spalling Spall are flakes of a material that are broken off a larger solid body and can be produced by a variety of mechanisms, including as a result of projectile impact, corrosion, weathering, cavitation, or excessive rolling pressure . Spalling and spallation both describe the process of surface failure in which spall is shed, and ultimately, structural failure Structural failure refers to loss of the load-carrying capacity of a component or member within a structure or of the structure itself. Structural failure is initiated when the material is stressed to its strength limit, thus causing fracture or excessive deformations. In a well-designed system, a localized failure should not cause immediate or. This is a particular problem where the concrete is exposed to salt water, as in bridges built in areas where salt is applied to roadways in winter, or in marine applications. Epoxy Epoxy or polyepoxide is a thermosetting polymer formed from reaction of an epoxide "resin" with polyamine "hardener". Epoxy has a wide range of applications, including fiber-reinforced plastic materials and general purpose adhesives-coated, galvanized Galvanization classically refers to any of several electrochemical processes named after the Italian scientist Luigi Galvani. Now the term generally refers to an electrodeposition process used to add a thin layer of another metal to an item made of steel, in order to prevent rusting. More recently, though, the term has been broadened in common or stainless steel In metallurgy stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass. Stainless steel does not stain, corrode, or rust as easily as ordinary steel, but it is not stain-proof. It is also called corrosion-resistant steel or CRES when the rebars may be employed in these situations at greater initial expense, but significantly lower expense over the service life of the project. Special care must be taken during the installation of epoxy-coated rebar, because even small cracks and failures in the coating can lead to intensified local chemical reactions not visible at the surface.
Fiber-reinforced polymer Fibre-reinforced plastic (also fibre-reinforced polymer) are composite materials made of a polymer matrix reinforced with fibres. The fibers are usually fiberglass, carbon, or aramid, while the polymer is usually an epoxy, vinylester or polyester thermosetting plastic. FRPs are commonly used in the aerospace, automotive, marine, and construction rebar is now also being used in high-corrosion environments. It is available in many forms, from spirals for reinforcing columns, to the common rod, to meshes and many other forms. Most commercially available rebars are made from unidirectional glassfibre reinforced thermoset resins.
Sizes and grades
U.S. sizes
Imperial bar designations represent the bar diameter in fractions of ⅛ inch, such that #8 = 8⁄8 inch = 1 inch diameter. Area = (bar size/9)2 such that area of #8 = (8/9)2 = 0.79 in2. This applies to #8 bars and smaller. Larger bars have a slightly larger diameter than the one computed using the ⅛ inch convention.
| Imperial
Bar Size |
"Soft"
Metric Size |
Weight
(lb⁄ft) |
Weight
(kg/m) |
Nominal Diameter
(in) |
Nominal Diameter
(mm) |
Nominal Area
(in²) |
Nominal Area
(mm²) |
|---|---|---|---|---|---|---|---|
| #3 | #10 | 0.376 | 0.561 | 0.375 = ⅜ | 9.525 | 0.11 | 71 |
| #4 | #13 | 0.668 | 0.996 | 0.500 = ½ | 12.7 | 0.20 | 129 |
| #5 | #16 | 1.043 | 1.556 | 0.625 = ⅝ | 15.875 | 0.31 | 200 |
| #6 | #19 | 1.502 | 2.24 | 0.750 = ¾ | 19.05 | 0.44 | 284 |
| #7 | #22 | 2.044 | 3.049 | 0.875 = ⅞ | 22.225 | 0.60 | 387 |
| #8 | #25 | 2.670 | 3.982 | 1.000 = 8⁄8 | 25.4 | 0.79 | 509 |
| #9 | #29 | 3.400 | 5.071 | 1.128 | 28.65 | 1.00 | 645 |
| #10 | #32 | 4.303 | 6.418 | 1.270 | 32.26 | 1.27 | 819 |
| #11 | #36 | 5.313 | 7.924 | 1.410 | 35.81 | 1.56 | 1006 |
| #12 | #40 | 6.424 | 9.619 | 1.50 | 38.1 | 1.76 | 1140 |
| #14 | #43 | 7.650 | 11.41 | 1.693 | 43 | 2.25 | 1452 |
| #18 | #57 | 13.60 | 20.284 | 2.257 | 57.33 | 4.00 | 2581 |
Canadian sizes
Metric bar designations represent the nominal bar diameter in millimeters, rounded to the nearest 5 mm.
| Metric
Bar Size |
Mass
(kg/m) |
Nominal Diameter
(mm) |
Cross-Sectional
Area (mm²) |
|---|---|---|---|
| 10M | 0.785 | 11.3 | 100 |
| 15M | 1.570 | 16.0 | 200 |
| 20M | 2.355 | 19.5 | 300 |
| 25M | 3.925 | 25.2 | 500 |
| 30M | 5.495 | 29.9 | 700 |
| 35M | 7.850 | 35.7 | 1000 |
| 45M | 11.775 | 43.7 | 1500 |
| 55M | 19.625 | 56.4 | 2500 |
European sizes
Metric bar designations represent the nominal bar diameter in millimetres. Bars in Europe will be specified to comply with the standard EN 10080 (awaiting introduction as of early 2007), although various national standards still remain in force (e.g. BS 4449 in the United Kingdom).
| Metric
Bar Size |
Mass
(kg/m) |
Nominal Diameter
(mm) |
Cross-Sectional
Area (mm²) |
|---|---|---|---|
| 6,0 | 0.222 | 6 | 28.3 |
| 8,0 | 0.395 | 8 | 50.3 |
| 10,0 | 0.617 | 10 | 78.5 |
| 12,0 | 0.888 | 12 | 113 |
| 14,0 | 1.21 | 14 | 154 |
| 16,0 | 1.579 | 16 | 201 |
| 20,0 | 2.467 | 20 | 314 |
| 25,0 | 3.855 | 25 | 491 |
| 28,0 | 4.83 | 28 | 616 |
| 32,0 | 6.316 | 32 | 804 |
| 40,0 | 9.868 | 40 | 1257 |
| 50,0 | 15.413 | 50 | 1963 |
Grades
Rebar is available in different grades and specifications that vary in yield strength The yield strength or yield point of a material is defined in engineering and materials science as the stress at which a material begins to deform plastically. Prior to the yield point the material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed some fraction of the, ultimate tensile strength, chemical composition In chemistry, the empirical formula of a chemical compound is the simplest whole number ratio of atoms of each element present in a compound. An empirical formula makes no reference to isomerism, structure, or absolute number of atoms. The empirical formula is used as standard for most ionic compounds, such as CaCl2, and for macromolecules, such, and percentage of elongation.
The grade designation is equal to the minimum yield strength of the bar in ksi The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force of one pound-force applied to an area of one square inch: (1000 psi) for example grade 60 rebar has a minimum yield strength of 60 ksi. Rebar is typically manufactured in grades 40, 60, and 75.
Common ASTM ASTM International , originally known as the American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services. The organization's headquarters is in West Conshohocken, Pennsylvania, about 5 miles specification are:[3]
- ASTM A82: Specification for Plain Steel Wire for Concrete Reinforcement
- ASTM A184/A184M: Specification for Fabricated Deformed Steel Bar Mats for Concrete Reinforcement
- ASTM A185: Specification for Welded Plain Steel Wire Fabric for Concrete Reinforcement
- ASTM A496: Specification for Deformed Steel Wire for Concrete Reinforcement
- ASTM A497: Specification for Welded Deformed Steel Wire Fabric for Concrete Reinforcement
- ASTM A615/A615M: Deformed and plain carbon-steel bars for concrete reinforcement
- ASTM A616/A616M: Specification for Rail-Steel Deformed and Plain Bars for Concrete Reinforcement
- ASTM A617/A617M: Specification for Axle-Steel Deformed and Plain Bars for Concrete Reinforcement
- ASTM A706/A706M: Low-alloy steel deformed and plain bars for concrete reinforcement
- ASTM A767/A767M: Specification for Zinc-Coated(Galvanized) Steel Bars for Concrete Reinforcement
- ASTM A775/A775M: Specification for Epoxy-Coated Reinforcing Steel Bars
- ASTM A934/A934M: Specification for Epoxy-Coated Prefabricated Steel Reinforcing Bars
- ASTM A955: Deformed and plain stainless-steel bars for concrete reinforcement
- ASTM A996: Rail-steel and axle-steel deformed bars for concrete reinforcement
ASTM marking designations are:
- 'S' billet A615
- 'I' rail A616
- 'IR' Rail Meeting Supplementary Requirements S1 A616
- 'A' Axle A617
- 'W' Low-alloy — A706
Historically in Europe, rebar is composed of mild steel material with a yield strength of approximately 250 N/mm². Modern rebar is composed of high-yield steel, with a yield strength more typically 500 N/mm². Rebar can be supplied with various grades of ductility Ductility is a mechanical property that describes the extent in which solid materials can be plastically deformed without fracture, with the more ductile steel capable of absorbing considerably greater energy when deformed - this can be of use in design to resist the forces from earthquakes An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. Earthquakes are measured with a seismometer; a device which also records is known as a seismograph. The for example.
Placing rebar
Rebar cages are fabricated either on or off the project site commonly with the help of hydraulic Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics is used for the generation, control, and transmission of power by the use of benders and shears, however for small or custom work a tool known as a Hickey - or hand rebar bender, is sufficient. The rebars are placed by rodbusters or concrete reinforcing ironworkers with bar supports separating the rebar from the concrete forms to establish concrete cover and ensure that proper embedment is achieved. The rebars in the cages are connected by welding or tying wires. For epoxy coated or galvanised rebars only the latter is possible.
Wed, 25 Aug 2010 14:06:15 GMT+00:00
SteelOrbis (registration) Iranian steelmaker Khorasan Steel produced 189459 mt of semi-finished steel (billet) and 196163 mt of finished steel products ( rebar ) in the first four ...
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Posted by lauramcc at August 9 2006 10 46 AM
DJerome
Fri, 16 Jul 2010 19:11:28 GM
City Name Specification Material Steel / Origin Price Change Notes Shanghai grade . rebar. 20 HRB400 Northern Taiwan 3510 - Shanghai Grade . Rebar. 16 HRB400 Sunshine 3520 25mm: 3700 Shanghai grade . rebar. 16 HRB400 West Side 3520 25mm: ...
