How to Check Quality & Select Steel Rebar for Indian Houses
There are different varieties of Steel rebars available from different companies. Selecting the best steel rebar for construction is important for the strength and durability of the structure. In this article, we are going to see how to check the quality and select the best steel rebars for the construction of a house based on type, brand, mass, dimension, grade, elongation, and chemical composition.
1. Check the Type of Steel rebar
Steel bars are classified into different types based on their manufacturing process. Some of the popular types of steel rebars are
1.1 TMT Bars
TMT bars are Thermo Mechanically Treated bars. They are manufactured by rapid colling to create a tough outer surface with a relatively ductile inner core. Hence TMT bars have a better balance between strength and ductility. In the present scenario, TMT bars are widely used for their following advantages.
- Superior strength.
- Good ductility and elongation.
- Better Ribs projection for bonding.
- Good weldability.
TMT Fe500 and TMT Fe500D are the two best choices for all types of House construction. Fe500D provides extra ductility. Fe500S are better suited for earthquake-prone zones.
1.2 CRS TMT Bars
CRS TMT bars are Corrosive Resistant TMT bars. They are TMT bars further treated to resist corrosion through epoxy coating or through similar methods. They are best suited for house construction in corrosion-prone zones like seashore areas.
1.3 HYSD Bars
HYSD bars are High Yield Strength Deformed bars. They are now replaced by TMT bars.
1.4 CTD bars
CTD bars are Cold Twisted Deformed bars. They are twisted at room temperature to increase strength. CTD bars have less strength, less ductility and they are highly prone to corrosion than other bars.
2. Visual Inspection for Rust and Identification Mark
Steel rebars should be free from rust and dust. They should have details of their Brand name, Diameter, and Grade like FE 500, FE 550 D, at every running meter. Some branded steel bars also come with a company tag.
3. Check for Uniform Mass/Weight
Steel rebars should have a uniform mass per unit length. So when you select the steel brand for your construction check whether all steel rebar of the same diameter and same length have the same weight.
4. Check for Minimum Mass/Weight
Check whether the Steel rebar has the following Minimum mass per meter as per the steel codebook.
You can also calculate the mass of the steel bar per meter from the famous d2/162 formula. Examples are given in my other post.
- The unit weight of steel is 7850 kg/m3.
- Mass per cross-sectional area per meter is 0.007850 kg/mm2 per meter.
Sometimes there may be a slight deviation in the mass of the steel rebar, but the deviation should not be greater than the tolerance percentage given below as per the Steel codebook.
Test Samples taken to check the mass of the steel bar should not be less than 500mm.
5. Check for Steel Grade/Strength
Steel rebars are classified into different grades based on their strength. For example, in the grade Fe415D, “Fe” stands for iron (steel) and “415” stands for Minimum Yield strength(tensile strength) and finally, the letter D denotes the Ductility of the steel rebar.
The minimum Yield strength and Ultimate tensile strength required for steel rebars of different grades are given below. You can check the strength and elongation of the rebar in laboratories through a Tensile Testing Machine such as UTM.
In the latest amendment of the steel codebook, newer grades have been added. These grades have higher ductility than the other grades and are best suitable for earthquake-prone zones.
6. Check for Length
Usually, steel rebars are supplied in the length of 12 meters for most types of construction, or in the form of coils in case of large construction works. The length of the steel rebar, as specified in the bar specification, shall not be less than 25 mm or greater than 75mm.
7. Check for Ribs Projection
In the case of High strength deformed bar and TMT bars, Ribs projection should be not less than the value given below. Ribs project helps in creating a good bond between steel and concrete.
8. Chemical Composition as per Indian steel codebook
9. Selection of Best Steel Rebar Brand for Construction of House
Cost is the main factor when it comes to the selection of steel brands. Some of the cheaper steels may not have required quality, at the same time some high-quality steel may be too costly for our requirement. Some of the popular well-known good-quality steel brands are given below.
TATA Steels – TATA Tiscom, TATA Tiscom SD
Tata is a highly trusted brand throughout India. TATA Tiscom is high strength TMT ribbed bar. They provide good strength, ductility, and elongation. TATA Tiscom SD is a super ductile steel rebar. They have a higher ductile ratio of 1.5 which makes them bend and not break during sudden loads. They are better suitable for buildings in seismic areas to resist earthquake loads.
JSW Steels – JSW Neo steel
JSW is another popular and trusted brand. JSW Neosteel 550D is a high-strength TMT ribbed ductile bar. They are famous for their uniform mass and finish.
Other Popular steel brands are Vizag Steel, Essar Steel, Kamadenu Steel, Amman Steel etc.
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