Steel Rebar

详情

Steel rebar specifications are defined by three main factors: size, grade (strength), and material type. These standards ensure that reinforced concrete has the necessary tensile strength to handle structural loads.
1. Rebar Sizes
Rebar size is designated by a number representing its nominal diameter. In the Imperial system (US), the number is the diameter in eighths of an inch. Metric sizes are the standard in the Philippines and Europe.

| Imperial Size | Metric Size | Diameter (in) | Diameter (mm) | Weight (lb/ft) | Weight (kg/m) |
|**-|**-|**-|**-|**-|**-|
| #3 | *0mm | 0.**5 | 9.**5 | 0.**6 | 0.**1 |
| #4 | *2mm | 0.**0 | *2.7 | 0.**8 | 0.**8 |
| #5 | *6mm | 0.**5 | *5.**5 | 1.**3 | 1.**8 |
| #6 | *0mm | 0.**0 | *9.*5 | 1.**2 | 2.**6 |
| #8 | *5mm | 1.**0 | *5.4 | 2.**0 | 3.**3 |
| #*0 | *2mm | 1.**0 | *2.*6 | 4.**3 | 6.**3 |

2. Strength Grades
The grade indicates the minimum yield strength—the point where the steel begins to deform permanently.

* Grade *3 (**0 MPa): Structural grade, often used for low-rise residential or light-duty work.
* Grade *0 (**5 MPa): Intermediate grade; common for residential walls and footings.
* Grade *0 (**5 MPa): High-tensile grade; the standard for high-rise buildings and heavy infrastructure.
* Grade *5/*0 (**0+ MPa): Specialty high-strength steel used in bridges and seismic-resistant structures.

3. Material Types & Coatings
Depending on the environment (e.g., coastal areas or chemical plants), different materials are used:

* Carbon Steel (Black Rebar): The most common type for general construction.
* Weldable Steel: Specifically manufactured (low-alloy) to be joined by welding without losing structural integrity.
* Epoxy-Coated: Coated in green epoxy to prevent rust in high-moisture environments.
* Galvanized: Zinc-coated for superior corrosion resistance compared to black rebar.
* Stainless Steel: The most expensive and durable option for extreme saltwater exposure.
* GFRP (Fiberglass): A rust-proof, non-conductive, and lightweight alternative to steel.

4. Standard Markings
Every piece of rebar has rolled-on markings that tell you four things:

   1. Producing Mill: A letter or symbol for the manufacturer.
   2. Bar Size: The number representing the diameter.
   3. Type of Steel: Usually S (Carbon), W (Weldable), or A (Axle).
   4. Grade Mark: A number or line indicating the strength (e.g., a "*0" or a single line for Grade *0)