Reinforcing Bars

Reinforcing Bars

Ferrous steel reinforcing bar, also commonly called rebar, is used to reinforce concrete and masonry structures, strengthening and holding concrete. It is most often formed with a patterned surface (usually described as deformed) to create a better bond with the concrete poured around it. There are no official deforming patterns, but the spacing, number and height of the marks is standardized and incorporated into the basic rebar standards. There are also plain bars, but these are used in only the most specific ways.

Rebar is known as a tensioning device because it holds concrete in a compressed state. Concrete is a very strong material when it is in compression, but it has almost no strength where carrying tensile loads is concerned. To overcome this, rebar is cast in poured concrete to carry these loads. Additionally, the design of the rods typically includes the deformity (in the form of heavy ridge patterns) that further support the binding of the rebar to the concrete.

Deformation standards are identified by the following:

  • The letter or symbol of the producer’s mill will be rolled into the rebar
  • The size of the bar is rolled into the rebar and appears as a numeral
  • The symbol for the type of steel (These are limited to S – carbon steel, I – rail steel, A – axle steel, W – low alloy steel, IR – rail meeting, SS – stainless steel, CS – low carbon chromium)
  • The grade of the rebar will be signified (40, 60, 75, 80, 100 or 120), or the addition of one, two, three or four lines that must be five deformations long will appear

Clearly, the markings do more than tag the deformations. In fact, each marking system provides details about the manufacturing and composition of each bar of reinforcing steel. The standards and grades available include ASTM International sizes and standards which are Imperial sizes, but there are metric equivalents too. EN 10080 metric designations are also available in addition to Canadian grades and sizes.

American builders and buyers will use the following grades and sizes

Bar #Diameter in inchesMetric #
3
0.37510
40.50013
50.62516
60.75019
70.87522
81.00025
91.12829
101.27032
111.41036
141.69343
182.25757

There are also three grades of Imperial size that have metric equivalents:

Inch gradeMetric gradePounds per square inchMegapascals
4028040,000280
6042060,000420
7552075,000520

There are many rules and guidelines for using various grades, and the following are applicable ASTM Standards by Grade:

40 & 506075300 & 350420520
SbilletA615A615A615A615MA615MA615M
IrailA616A616A996MA996M
IRRail Meeting Supplementary
Requirements S1
A616A616
AaxleA617A617A996MA996M
WLow-alloyA706A706M

European builders and buyers will use EN10800 metric designations. These appear as a K followed by the mass of the bar in kilograms, per one meter of length. For instance, K3 weighs three kilograms per meter.

Canadian rebar is identified with a symbol for the mill followed by the size of the bar. This will feature numerals and then the grade symbol.

Historically, rebar has only been in use since the 1400s, and the use of ferrous steel was introduced to eliminate the risks of corrosion. Though it is possible to find other metals or grades, it is steel rebar that Gemina has available. All standard sizes and grades are in stock and produced in top quality mills in Turkey, the European Union and Asia.