If you are planning to work with concrete or masonry, particularly large platforms, walls, floors, and ceilings, a word you may be encountering is rebar. Sure, you might know that rebar is often found in concrete and structures built of stone.
However, what exactly is it? How is it made and why is it used?
We will answer all of these questions right here and now.
What is Rebar?
The word rebar is actually a combination of two words, and it stands for reinforcing bar. Rebar is also known as reinforcing or reinforcement steel. It consists of a special steel bar or a mesh made of many small steel wires.
Rebar is used as a tension device and a reinforcement mechanism in concrete and masonry, with the aim being to strengthen and stabilize the concrete under tension.
Simply put, rebar is a steel bar placed inside of stone or concrete with the aim of reinforcing it and helping it to withstand great amounts of pressure and tension.
Something to be aware of is that there are a few different types out there, and each is used for a specific purpose. Here is a list of the most common types of rebar used in construction:
- Carbon Steel Rebar: This type of rebar is very cost-effective, it’s strong, and usually used in concrete pouring.
- GFRP: This rebar is an alternative to traditional carbon steel. It is made of fiberglass and has great tensile strength.
- Galvanized Rebar: Galvanized rebar is coated with zinc using a variety of processes and is greatly resistant to corrosion.
- Stainless Steel: Stainless steel rebar is used for purposes where corrosion is an issue, but zinc cannot be used to due to its tendency to galvanize. It’s very expensive and rarely used.
- Epoxy Rebar: Rebar coated in epoxy is very modern and economical. It is very resistant to corrosion, yet is not great due to motion damaging the coating.
Additionally, rebar comes in a variety of sizes.
How is Rebar Made?
Something that is important to note is that rebar used to be made out of new steel. However, during the 1960s, rebar started being made out of scrap metal. At this time, rebar contains up to 97% recycled materials, making it fairly eco-friendly.
Most rebar, the type made out of steel, is made by melting scrap steel in an arc furnace. The melted steel is then cast into billets, which are then hot rolled into a bar. After the bar is rolled, it is then cut to the desired length using special machinery, and it is then put into an air bed for air cooling.
There is also coiled rebar, which is just like normal rebar, but instead of being a straight bar, it features a coiled shape. This type of rebar, after it is air-cooled, is then sent into a reforming tub, where it is then spooled and shaped into a coil, and then cut into the appropriate shapes and lengths.
Why is Rebar Used in Construction?
Now that you know what rebar is, what the different types are, and how it is made, you might be wondering what it is actually used for, and why it is used. The point here is that rebar makes concrete stronger.
For one, over time, concrete will crack, and when concrete cracks, it becomes much weaker. Cracked concrete loses much of its structural integrity. Moisture and air can get into those cracks, thus speeding up the degradation of the concrete.
Although this is not the primary use of rebar, it will definitely help stop these cracks from forming to a certain degree. The main purpose of rebar in this sense is to control where the cracks occur, thus making it easier to predict these spots.
Moreover, when it comes to strength and resilience, steel rebar is much stronger and better able to withstand large amounts of pressure, weight, and tension than concrete is. By adding rebar to concrete, and by spacing it out a certain way, it can allow concrete to carry much more weight, to handle more pressure, and to deal with much more tension than it otherwise could.
Concrete is absolutely horrible at dealing with tensile strength, and just a bit of movement, say from an earthquake, can decimate it. However, rebar helps to stabilize the concrete so it can deal with more weight and tensile pressure, and it also helps slow down the degradation of the concrete over time.
What Else Can Be Done with Rebar?
Rebar is of course primarily used to strengthen concrete, whether for big slabs, sidewalks, foundations, walls, ceilings, roofs, and more. However, whether you have old rebar from construction projects that have been torn down, or some scrap rebar laying around, it can be used for other things.
Generally speaking, many artists will use old rebar to make metal art installations. You could also use old rebar to make fences, to make frames for small sheds, to make staircase railings, and for anything else where a metal bar is called for or would come in handy.
Of course, if you don’t need the rebar anymore, this kind of steel can fetch a good price, or in other words, you could always sell it as scrap metal. If you happen to have an arc furnace laying around, you can also melt it down and turn it into anything your heart desires.
The bottom line is that many structures in our modern world that are built of concrete, whether large skyscrapers, subway train tunnels, and sidewalks alike, all contain rebar. It simply would not be possible for any of these structures to maintain their structural integrity over a prolonged period of time without those steel reinforcing bars.