Rebar is the short form of Reinforcing Bar which is also known as reinforcing steel or reinforcement steel. It is used in reinforced concrete for the purpose of increasing the tensile strength of the overall structure. In order to allow the steel bar to create better bonding with the concrete, the surface of Rebar is deformed with ribs and indentation, it helps to reduce the risk of slippage.
Different types of deformed steel bars are available to meet different requirements and purposes.
1. Thermo Mechanically Treated Bars (TMT Bars)
A high-strength reinforcement bar which is the latest induction in the mild steel bars with the highest quality standard, has a high level of strength, bending ability, ductility, and welding ability. It is manufactured under a process called Thermo Mechanical Treatment, a metallurgical technique that has combined mechanical deformation such as forging, rolling, and compression with the thermal processes. By passing hot rolled steel billets through water, this process hardens its surface and increases the tensile strength whereas its inner core still stays at a warmer temperature, and hence, it has a hard outer surface with a soft inner core. It is resistant to rust and corrosion which allow them to be a better option for high rise buildings, bridges in a humid area, airport, or even other structures that required industrial-grade strength and high rigidity.
2. High Yielding Strength Deformed Bars (HYSD)
Cold twisted steel bar with ribs and the surface is deformed which is extensively used for reinforcement purposes in construction. Due to its deformed surface, it minimizes the possibility of slippage in concrete and creates a better bonding with the cement concrete. This type of bar has lower carbon content which results in 100% welding capability, good strength, and ductility.
Since High Yielding Strength Deformed Bars has high tensile strength, it is suitable for the construction process where requires a lot of bending and modification. It can be bend 180° without causing any fracture and cracks on the exterior. It is widely used as reinforcement in mass concrete such as residential buildings, roads, pile bases precast concrete work, commercial and industrial structure. The structural properties of HYSD have made it easier to design and can be welded by using electric flash butt welding or arc welding. In addition, the reformed bar should have at least 40% higher on the strength of bonds in comparison with the plain round bars in the same nominal size.
High Yielding Strength Deformed Bars are normally produced in sizes from diameter 4mm up to 50mm with the corresponding weights per meter length at up to 154.10 N. In terms of the strength, both High Yielding Strength Deformed Bars and Mild Steel Bar are weaker than Thermo Mechanically Treated Bars. Here we summaries a few points between TMT and HYSD Bars:
TMT Bars HYSD Bars
No surface flaws in twisting Some surface flaws in twisting
Able to save up to 20% of steel Standard/Normal steel consumption
High ductility Lesser ductility
Strong resistant to corrosion Moderate level of corrosion resistant
Lighter in weight Heavier in weight
Earthquake resistant for high tensile strength Lower tensile strength
Cost-saving (less transportation cost, labor cost) Less cost saving
Other types of rebar:
3. Carbon Steel Rebar
It is commonly known as Black Bar due to its color and made up of carbon steel. The key drawback of the Carbon Steel Rebar is its easy-corrosive characteristic which has adversely affect the structure and concrete of the building.
4. Epoxy-Coated Rebar
It is the black rebar added with a coating of epoxy to make it has minimum 70 times stronger resistance to corrosion, but it has the same tensile strength as black rebar. When the coating of epoxy damaging over a period of time, it causes less resistance to corrosion.
5. Galvanized Rebar
Galvanized Rebar is reinforcing steel coated with a protective layer of zinc metal to increase its level of corrosive resistance. A coating of zinc is applied to the bare and clean steel by immersing into a bath of liquid zinc which is heated up to 450ºC and then allows to cool down prior conformance of appropriate specification. However, it has only 40 times stronger resistance to corrosion than black rebar. In comparison with the Epoxy-Coated Rebar, the galvanized coating is more durable and hard to damage. So it has more value and price will be more expensive than Epoxy-Coated Rebar.
6. Stainless Steel Rebar
Stainless steel rebar consists of a minimum 12% of chromium and up to 12% of nickel, it offers a good combination of high strength, fatigue resistance, and ductility. In comparison, It has up to 1500 times strong resistance to corrosion than the black bar. Therefore, pricing is obviously more expensive than other types of rebar. Stainless Steel Rebar is suitable to be used for marine structures such as sea wall, bridge, ramps, barriers, anchoring system, or other process plants and infrastructure of chemicals.
Key advantages of Stainless Steel Reinforcing Bars:
- Strong corrosion resistance
- High strength
- Good weld-ability
- low maintenance cost
- No coating to crack or degrade
- Good high and low-temperature mechanical properties
7. Glass Fiber Reinforced Polymer (GFRP)
Glass-Fiber-Reinforced-Polymer is a composite such as carbon fiber, it does not contain any metal elements and so does not rust. It is a cost-effective construction material as it gives a concrete structure long lifespan without major maintenance. It can extend the lifespan of a public structure where corrosion is a challenging issue caused by the environment. As global warming getting concerns, the fiberglass reinforcement material is gaining more popularity due to its characteristics. In comparison with other reinforcement materials, GFRP is lighter than steel and has two times the tensile strength of steel. It is also non-conductive to heat/electricity, invulnerable to chloride ions and other chemical components, these advantage has made it an ideal choice for applying in power generation plants or other scientific facilities. GFRP also can be used as a cladding material and bent into wireframe structures.
MecHero supply a wide range of rebar and other steel product in Malaysia. Please do not hesitate to contact us at 011-7001 7687 or submit enquiry from our website. Our steel specialists are ready to give you a professional service.