A Comprehensive Guide to Rebar Types: A1, A2, A3, and A4

Choosing the right type of rebar for concrete structures is one of the important factors in increasing the durability and strength of the structure. Rebars are classified into types of rebar a1 a2 a3 and a4 based on their mechanical properties and tread pattern. Rebar A1 is simple and without tread and is mostly used to reinforce sections of structures that require high flexibility. Rebars A2 and A3 have tread and have greater strength and hardness than A1, respectively. A2 is mostly used in semi-heavy structures and A3 in heavy and solid structures. Rebar A4 is also designed with the highest strength and hardness for special and industrial projects. It should be noted that according to Russian standards, rebars a5 and a6 are also defined, which are not produced in Iran.

If you are active in the steel market or are one of those people who are constantly in construction, you definitely know that when buying, you are faced with a wide variety of rebars. Some rebars, such as: A2 and A3T ribbed rebars, are more commonly used in construction.

The difference between a2 and a3 rebar is in ductility, tensile strength and how to use it in construction projects, and choosing them correctly can help improve the quality and useful life of the structure. In this article, we will examine the appearance and mechanical differences of these rebars so that you can become familiar with the difference between a2 and a3 rebar, a3 rebar, types of rebar and other specifications of these products. After reading this content, you can easily distinguish the difference between a1 a2 a3 rebar and the difference between a3 and a4 rebar. Also, the price of Yazd rebar and other factories in plain and ribbed types is posted daily on the Ceramland website. You can visit the site to inquire about prices.

Types of rebar a1 a2 a3

A1 rebar with a smooth surface and no tread is known as plain rebar. This type of rebar has no protrusions or grooves on its surface in terms of appearance and is used in projects that require welding. Unlike A1, A2 rebar has simple and uniform treads that are located in a spiral on the surface of the rebar. A3 rebar with cross or cross treads has greater resistance than A2 and is used as A3 ribbed rebar in main load-bearing structures. A4 rebar with compound treads is the most advanced type of rebar used for projects with high mechanical requirements.

The appearance of the rebars can be used as an important criterion in selecting the type of rebar for different projects. The appearance difference between a2 and a3 rebar is evident in the shape of their treads; These differences affect the strength and applications of these two types of rebar. Considering the difference between A2 and A3 rebar, in general, it can be said that these rebars are used more in main load-bearing structures such as beams and columns due to their more complex treads and higher strength.

Finally, the differences in appearance and functionality of A1, A2, A3, and A4 rebar indicate that each of these rebars is suitable for specific construction conditions. Choosing the right rebar based on these differences can play an important role in increasing the safety and efficiency of structures. By viewing photos of A2 and A3 rebar and other types of rebar, you can gain a good understanding of these products.

Introduction to types of rebar:

A1 rebar (soft and without tread): The first group is A1 rebar, whose code name is F240 with a strength class of 240, which is known as A1 or plain rebar and there is no tread pattern on their surface. They are divided into the soft rebar category in terms of hardness. A1 rebars have different characteristics.

For example, the yield stress and rupture strength of this series of rebars are defined as 2300 and 3800 kg/cm2, respectively. The plastic changes in these rebars are mentioned as close to 25 percent. Grade A1 rebars are used for forging and welding. The reason for using this product for welding is the low carbon content in the chemical composition of the rebar.

A2 rebar: What is A2 rebar? A rebar that is ribbed and is known by the characteristic symbol S340. This semi-hard rebar is more resistant than A1 rebar in terms of strength. Welding on this rebar grade is not a good idea, but if forced, you can also weld A2 rebar.

A3 Rebar: What is A3 Rebar? The A3 rebar shape with truss treads is known as a rebar with high resistance to tensile forces. This rebar is used in projects that require high resistance to pressure. Due to its greater stiffness, A3 reinforcement is used in longitudinal structures of beams and columns and is known as the main rebar of the structure. Also, the relative plastic stress is 14 percent and is known as dry rebar.

A4 rebar: This rebar with compound treads and very high strength is used for special projects and structures that require high strength. Due to its high mechanical properties, this type of rebar is less used in general construction projects and is more used in industrial projects and large structures.

Types of Ribbed and Plain Rebar

Rebar types are divided into two general categories in terms of appearance: plain and ribbed. Plain rebar, known as A1 rebar, has a smooth surface without any protrusions. These rebars are mostly used in cases that require flexibility and welding. On the other hand, ribbed rebar is used to increase the strength of concrete due to the presence of various rebar treads on its surface. Types of ribbed rebar include A2 rebar, A3 rebar, and A4 rebar.

A2 rebar has medium strength and is used in shear structures such as stirrups and shear walls. A3 rebar has higher strength than A2 and is used in main load-bearing structures such as beams and columns. A4 rebar with compound treads is the most advanced type of ribbed rebar and is used for projects with high mechanical requirements.

In general, the difference between A3 and A4 rebar is mainly in the type and complexity of the treads, as well as their mechanical strength. Each type of rebar is designed for specific applications, and its correct selection can have a significant impact on the performance of structures. In the following, we will further examine the use of A2 and A3 rebar and the difference between A3 and A2 rebar.

Classification of rebar types

One way to identify a2 or a3 yoke rebar is their tread shape. The tread shape of A2 is single and parallel, and in A3 rebar it is crosswise and seven and eight. In the design of the foundation, A3 longitudinal product and A2 transverse rebar are used. A3 rebar is more brittle and fragile, but A2 is more flexible. You can also see the price difference between a2 and a3 rebar on the Iron Center website.

Note that to identify the type of rebar, in addition to examining the appearance of the tread, also examine the chemical composition of the rebar. You can see photos of a2 and a3 rebar in this article. The reason for emphasizing all these reviews is that profit-seeking people are offering rebars with A3 tread type and A2 grade alloy compositions to the market. The price of rebar can vary depending on the difference between a2 and a3 rebar.

A point to note is that due to the brittleness and low ductility of a3 rebars, their use is prohibited in earthquake-prone areas and for cases such as the construction of columns, shear walls, beams, joists and slabs. Also, A4 rebars are not used in construction and are more suitable for heavy work. The following are the differences in the characteristics of a3, a2, a1 and a4 rebar types in the relevant tables.

In order to accurately identify the types of reinforcement and also to be able to distinguish between a2 and a3 rebar, the weight and dimensions table of this product will be very useful for you. The following table provides you with the specifications of rebars with a nominal diameter of 8 to 32 mm.

Rebar differences in terms of mechanical properties

Among the important mechanical properties for identifying plain and ribbed rebars are the yield stress and rupture stress:

A1 rebar, due to its lack of rib, has the lowest resistance to tensile forces and is used more in cases where high flexibility and easy deformation are required. A2 rebar is used with simple treads and medium strength, is stronger than A1 against tensile forces and is suitable for shear structures. This rebar is known for its yield stress of 3000 kg/cm2 and its ultimate stress of 5000 kg/cm2. Other characteristics of A2 rebar include the amount of plastic deformation (19%).

Choosing the right rebar is crucial for enhancing the durability and strength of concrete structures. Rebars are classified into types A1, A2, A3, and A4 based on their mechanical properties and tread patterns. Understanding their differences ensures optimal performance in construction projects.

Types of Rebar: A1, A2, A3, and A4

1. A1 Rebar (Plain Rebar – F240)

• Appearance: Smooth surface, no tread

• Properties:

  • High flexibility

  • Yield stress: 2300 kg/cm²

  • Rupture strength: 3800 kg/cm²

  • Plastic deformation: ~25%

• Uses:

  • Projects requiring welding

  • Non-load-bearing structures

  • Forging applications

2. A2 Rebar (Spiral Ribbed – S340)

• Appearance: Simple, uniform spiral treads

• Properties:

  • Semi-hard, moderate strength

  • Yield stress: 3000 kg/cm²

  • Rupture strength: 5000 kg/cm²

  • Plastic deformation: ~19%

• Uses:

  • Semi-heavy structures

  • Shear walls and stirrups

  • Limited welding applications

3. A3 Rebar (Cross-Ribbed – S400)

• Appearance: Cross (herringbone) tread pattern

• Properties:

  • High tensile strength

  • Yield stress: 4000 kg/cm²

  • Rupture strength: 6000 kg/cm²

  • Plastic deformation: ~14% (more brittle than A2)

• Uses:

  • Heavy load-bearing structures (beams, columns)

  • Main reinforcement in concrete slabs

  • Not recommended for seismic zones

4. A4 Rebar (Compound Ribbed – S500)

• Appearance: Complex tread pattern

• Properties:

  • Highest strength and hardness

  • Used in industrial and special projects

• Uses:

  • Large-scale infrastructure

  • High-stress applications

  • Not common in standard construction

Key Differences Between A2 and A3 Rebar

How to Identify Rebar Types

• A1: Smooth, no tread

• A2: Spiral ribs

• A3: Cross ribs (7-8 pattern)

• A4: Compound ribs (highest strength)

Rebar Selection Tips

✔ For welding: Use A1 (plain rebar)
✔ For shear reinforcement: A2 is ideal
✔ For load-bearing structures: A3 provides superior strength
✔ For industrial projects: A4 is best for extreme conditions

Rebar Weight and Dimensions Chart

Final Recommendations

• For earthquake-prone areas: Avoid A3 due to brittleness.

• For welding needs: A1 is the best choice.

• For cost-effective reinforcement: A2 offers a balance of strength and flexibility.

For daily rebar prices (including Yazd rebar), visit Ceramland’s website for updated listings.

By understanding these differences, you can make informed decisions to enhance the safety and longevity of your construction projects.