What is Rebar?

Steel reinforcement bars or rebars are wont to improve the lastingness of the concrete, since concrete is extremely weak in tension, but is robust in compression. Steel is merely used as rebar thanks to the elongation of steel due to high temperatures (thermal expansion coefficient) nearly adequate to that of concrete.

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Rebar sizes

m) Nominal Diameter (in) Nominal Diameter (mm) Nominal Area(in²) Nominal Area (mm²)
#3 #10 0.376 0.561 0.375 9.525 0.11 71
#4 #13 0.668 0.996 0.500 12.7 0.2 129
#5 #16 1.043 1.556 0.625 15.875 0.31 200
#6 #19 1.502 2.24 0.750 19.05 0.44 284
#7 #22 2.044 3.049 0.875 22.225 0.6 387
#8 #25 2.67 3.982 1.000 25.4 0.79 509
#9 #29 3.4 5.071 1.128 28.65 1 645
#10 #32 4.303 6.418 1.27 32.26 1.27 819
#11 #36 5.313 7.924 1.41 35.81 1.56 1006
#14 #43 7.65 11.41 1.693 43 2.25 1452
#18 #57 13.6 20.284 2.257 57.33 4 2581

Imperial Bar Size	"Soft" Metric Size	Weight per unit length (lb/ft)	Mass per unit length (kg/m)	Nominal Diameter (in)	Nominal Diameter (mm)	Nominal Area(in²)	Nominal Area (mm²)
#3	#10	0.376	0.561	0.375	9.525	0.11	71
#4	#13	0.668	0.996	0.500	12.7	0.2	129
#5	#16	1.043	1.556	0.625	15.875	0.31	200
#6	#19	1.502	2.24	0.750	19.05	0.44	284
#7	#22	2.044	3.049	0.875	22.225	0.6	387
#8	#25	2.67	3.982	1.000	25.4	0.79	509
#9	#29	3.4	5.071	1.128	28.65	1	645
#10	#32	4.303	6.418	1.27	32.26	1.27	819
#11	#36	5.313	7.924	1.41	35.81	1.56	1006
#14	#43	7.65	11.41	1.693	43	2.25	1452
#18	#57	13.6	20.284	2.257	57.33	4	2581

what is rebar made of

Grades of Rebar in Different Codes

Table 1: Grades of Rebar in Different Codes

Types of Steel Reinforcement Bars

The major types of steel bars used in the construction are as follows,

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1. Mild Steel Bar

The surface of the low-carbon steel bars are plain and round in shape. they're available in various sizes of 6 mm to 50 mm. they're utilized in concrete for special purposes, like dowels at expansion joints, where bars must slide during a metal or paper sleeve, for contraction joints in roads and runways, and for column spirals. they're easy to chop and bend without damage.

For structural buildings like bridges and other heavy structures, the mild steel bar isn't recommended thanks to no great bonding between concrete and steel, slippage, and strength.

Grades in mild steel bars

1. Mild Steel Bars

Mild steel bars grade-I designated as Fe 410-S or Grade 60.
Mild steel bars grade-II designated as Fe-410-o or Grade 40.

2. Medium Tensile Steel Bars designated as Fe- 540-w-ht or Grade 75.

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Physical Requirement of Mild Steel Bars

Table 2:Physical Requirement of Mild Steel Bars

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2. Deformed Steel Bar

Deformed steel bars have ribs, lugs, and indentation on the surface of the bar, which reduces the major problem that is faced by mild steel bars due to slippage and good bonding is achieved between concrete and rebar. The tensile properties are higher compared to other rebars. These bars are produced in sections from 6 mm to 50 mm dia.

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Types of Deformed Steel Bars

1. Thermo Mechanically Treated Bars

Thermo Mechanically Treated Bars are hot treated bars that are high in strength used in reinforced cement concrete (RCC) work. It is the latest induction in the MS steel bars with superior properties such as strength, ductility, welding ability, bending ability, and highest quality standards at the international level.

Characteristics of Thermo Mechanically Treated Rebars

Better ductility and malleability
High yield strength and toughness
More bonding strength
Earthquake resistance
Corrosion resistance
High thermal resistance
Economical and safe in use
No loss in strength at welded joints
Ordinary electrodes used for welding the joints

2. High Strength Deformed Bars

High strength deformed bars are cold twisted steel bars with lugs, ribs, projection, or deformation on the surface. It the extensively and majorly used for reinforcement purposes in construction. These bars are produced in sizes or sections from 4 mm to 50 mm in diameter.

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Characteristics of High Strength Deformed Rebar

Low carbon value – High Strength Deformed Bars have a lower carbon level, resulting in good ductility, strength, and welding ability.
Superior bonding strength – High Strength Deformed bars are well known for their excellent bonding strength when used with concrete.
Welding capability – Since these bars have lower carbon content, they have 100% welding capability than conventional bars.
High tensile strength – High Strength Deformed bars feature high tensile strength. They offer a great asset in the construction process, where a lot of bending and re-bending is required.
Wide application range – These bars have a wide application range like in building residential, commercial, and industrial structures, bridges, etc.
Satisfactorily malleability – Min. weight and max. strength. Also, suitable for both compression and tension reinforcement work.

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3. Other Types of Rebars

Also, we can categorize rebars depending on the type of material used in the production of rebar, as below

1. European Rebar

European rebar is formed of manganese, which makes them bend easily. They’re not suitable to be used in areas that are susceptible to extreme weather or geological effects, like earthquakes, hurricanes, or tornadoes. the value of this rebar is low.

2. Carbon Steel Rebar

As the name represents, it's made from steel and is usually referred to as Black Bar thanks to carbon color. the most drawback of this rebar is that it corrodes, which adversely affects the concrete and structure. The lastingness ratio including the worth makes black rebar one among the simplest choices.

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3. Epoxy-Coated Rebar

Epoxy-coated rebar is black rebar with an epoxy coat. it's an equivalent lastingness but is 70 to 1,700 times more immune to corrosion. However, the epoxy coating is incredibly delicate. The greater the damage to the coating, the less immune to corrosion.

4. Galvanized Rebar

Galvanized rebar is merely forty times more immune to corrosion than black rebar, but it's harder to wreck the coating of galvanized rebar. therein respect, it's more value than epoxy-coated rebar. However, it's about 40% costlier than epoxy-coated rebar.

5. Glass-Fiber-Reinforced-Polymer

Glass Fiber Reinforced Polymer is formed from carbon fiber. because it is formed from fiber, bending isn't allowed. it's very immune to corrosion and is expensive in comparison to other rebars.

6. Stainless Steel Rebar

Stainless steel rebar is that the costliest reinforcing bar available, about eight times the worth of epoxy-coated rebar. it's also the simplest rebar available for many projects. However, using chrome steel altogether but the foremost unique of circumstances is usually overkill. But, for those that have a reason to use it, chrome steel rebar 1,500 times more immune to corrosion than a black bar; it's more immune to damage than any of the opposite corrosive-resistant or corrosive-proof types or rebar, and it is often bent within the field.

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Tuesday, October 13, 2020

Rebar Sizes and Grades of Steel Reinforcement [What is Rebar?]