What is Rebar made of?
The construction process has evolved over the years with new ideas, approaches, and applications, all this to ensure longevity and greater building life. One such evolution is Rebar.
Since the concrete is very weak in tension, rebar helps to improve the tensile strength of the concrete. Rebar is a reinforcing bar. Generally, steel bars are used as rebar as steel’s thermal expansion nearly equals that of concrete.
Therefore, rebar enforces the tensile strength required for the concrete to stay in place and makes sure it will last as long as your structure does. Read along to understand what rebar is made of, how it can be recycled, and how & why it can be used in construction.
How Rebar is Made?
Rebar is usually made from a mild or high yield steel of grade 250 or 250 N/mm2 with great tensile strength. Steel (carbon or alloy) is melted down to liquid form, which requires an extreme amount of heat to achieve. Once melted, the liquid steel is pulled through small round openings to give the rebar its shape.
First, most rebar produced in North America is produced using an EAF steelmaking process, or Electric Arc Furnace. Here, scrap steel is collected from various sources at the steel mill and put into a large ladle where the steel is then melted at temperatures up to 1,800° Fahrenheit. In this state, the molten steel will be poured into a casting.
To make rebar, scrap steel undergoes several processes before turning into a finished product:
> Melt the steel
First and foremost, the steel is melted down to a liquid form, which requires an excessive amount of heat. The scrap steel collected is put into a large ladle and melted at a temperature of 1,800° Fahrenheit.
> Pour for shape
This melted steel is now poured into the tundish and fed into a series of casters where the steel takes its shape. Tundish helps to avoid splashing of the molted steel. The shape formed is known as billets and later on, it is processed to form the rebar.
> Roughing Mill
After the caster, the rebar goes to the roughing mill. Here, the larger billets are hot rolled into small shapes by continuously reducing the billet at each stand on the roughing position.
> Finishing Point
The billets are now passed through the intermediate section of the rolling mill. Here, the billets are given the shape of bars. From this intermediate section, the bars are passed through the finishing section to give them their final shape. Once the steel gets its final shape, it is given the twist and groves called the ‘tied knot’ shape. This shape ensures the rebar stays at a firm position while inside a structure.
> Cutting and cooling section
These bars now enter the cutting section, where they are chopped to a specific length as programmed by the mill operator. From here the bars are taken onto the cooling bed where the bars are cooled back to room temperature before being sold to the customer’s specific length.
Considering the hazardousness and to prevent any accidents from happening, the rebar ends are often covered with plastic caps.
The rebar is then bundled and packed according to customer specifications and distributed straight from the manufacturer to the job site.
Additional read: What Type of Rebar Grade is Right for Your Project?
Reuse and recycling of Rebar
Rebars can be costly and recycling them can help you gather funds for your next project. After the construction site is demolished, try looking for scrap companies or junkyards. They will pay you as per ton for all the scrap collected. If the rebars have concrete on them then the affected section can be cut off.
Also, make sure the rebars are long enough to be used later. It is also advisable to avoid rusted or corroded rebars, as they could pose a safety risk.
The scrap recycling can be combined with other steel products, re-formed, or melted down for any other shape.
How to work with it (Rebar)?
Depending upon the type of rebar they can have several applications. Rebars can be used in all types of construction such as floor slabs, stairs, and roof constructions.
> Certain kinds of rebars can be welded, but it is possible that the welding is weak and it won’t be able to bear any weight. ASTM A706 is the grade you are looking for in this case, this will surely give you a strong weld.
> Rebars can be used for forging, use in typical ironwork projects like making leaves, brackets, and much more.
> You can also machine it. Some large-size rebars are used as anchors. Meaning they’ll thread the ends and fit on a big nut.
Why & How Rebar Used in Construction?
Rebars are used in concrete construction, thus adding long-term strength to the building, foundation, pool, and other structures.
There are several ways in which rebars support reinforcement concrete construction such as:
> Primary Reinforcement – used to ensure that the structure can handle the load of the structural element and the environment where it is placed.
> Secondary Reinforcement – This adds durability and aesthetics; they provide enough resistance to limit cracking and stress caused by temperature changes and shrinkage.
> Rebars are also used to provide localized resistance that spreads the load impact across a wider region.
> Rebars also hold other steel bars in the correct position to handle their loads.
Looking for something with good tensile strength and a metal favorable to concrete, rebars are your answer. It is very much important to choose the right rebar sizes for your project as it can yield several benefits to your construction projects.
If you have any confusion regarding rebars usage, sizes, types, and cost then reach out to us at Florida Lumber, we’ll be more than happy to help.