Why Concrete Needs Rebar Reinforcement?
Concrete is exceptionally great and is exceptionally strong when it comes to compression. However, it doesn’t have much tension strength. When you are ready to begin a cement or concrete construction projects, the term rebar is constantly tossed around whenever planning and deciding the materials to buy. Most concrete contractors know that concrete is prone to cracks over a long period of time. That is why they are considering reinforcing rebar and other supporting materials to provide structural strength to concrete.
But what is rebar? What does it exactly do for the projects that make it so essential? Let’s begin knowing rebar reinforcement, its different characteristics, and the basics.
What is Rebar?
Rebar is the commonly used term for reinforcing steel bars that are used to strengthen concrete. Rebar is generally made from various and different grades of steel and alloys. Stainless steel rebar is very resistant to rust and is often utilized to construct commercial buildings and concrete driveways. Rebar helps in upholding the building’s strength and compression by supporting it in a compressed state.
The materials used to create rebar apart from different steel and alloys also include steel billets. These materials commonly come from steel debris and railroad tracks. Indeed, rebar is marked with a recognizing symbol, indicating where it was being produced.
So do you need to reinforce rebar to concrete? A question that is primarily asked by interested purchasers, clients, and even contractors.
Not all construction projects require the utilization of rebar reinforcement. However, simply adding rebar will largely reduce the number or cracks that usually appear in surface areas over time. Also, rebar makes concrete numerous times more resistant to failure. It also provides tensile strength using reinforcing bars. If you want to make the concrete more structural, rebar can provide stronger support than any reinforcing fiberglass, steel wires or other products available in the market. Why? Because rebar solely provides structural strength in its own right.
Common Physical Properties of Rebar
Rebar has been used for so long as a strengthening agent for concrete. Some ridges enable the concrete to adhere to rebar so that it will not slide around inside the slabs quickly. Also, different grades and sizes of steel are accessible to offer various levels of strength.
Now, we look for some properties that make rebar an excellent option for reinforcing concrete structures.
1. Expansion
When rebar is finally embedded in the concrete, it should have a thermal coefficient that is very identical to the concrete as possible. On the other hand, rebar has to expand and contract at an equal rate. Why? It is because the concrete has weaker tensile strength. Therefore, spalling might occur if there might be tension between the concrete and rebar due to the different expansion rates.
In terms of heat, carbonation from atmospheric CO2 and chloride from salts can get through the concrete layer, reaching the rebar. When oxygen and water contact the rebar reinforcement, the steel starts to oxidize or corrode. Iron in the steel will quickly react with water and then oxidized right after. On the other hand, rust develops and causes the rebar to expand widely. Therefore, the expansion has sufficient force that drives the concrete to crack during tension.
2. Rusting
Usually, an ordinary person who finds rust on steels will be alarmed immediately. Concrete contractors may find themselves in the same position, but they shouldn’t be alarmed when they see rebar rust. A certain amount of rust being discovered isn’t only expected but surprisingly acceptable. The main issue here is whether the rust can cause significant corrosion in the steel bars. Then if so, the rebar might not be used for concrete.
According to ASTM (American Society for Testing Materials), rebar reinforcement should be satisfactory and strictly meet ASTM standards despite the rust found outside the bars. The rust level should also fall under ASTM specification requirements for brush testing. If you then notice rust on rebar, then make sure to conform to ASTM standards before reinforcing it to concrete.
3. Low Magnetic Permeability
For concrete structures that will require a lower magnetic field, stainless steel rebar can lessen magnetism. Therefore, it ensures that the processes and machinery within individual buildings can receive no disruption. It is suitable for facilities like the following:
· Medical facilities with MRI machines
· Hospitals and
· Tool booths that have electronic pass detection
· Chemical plants
· Laboratories
Some rebar forms often create internal magnetic fields that make it difficult to operate a few equipment and machinery types. Nevertheless, stainless steels do not much create a magnetic field. Hence, it does not totally affect or disrupt technology.
4. Grounding
Although rebar is made of various metals, a particular foundation’s actual electrical conductor is the concrete. Hence, the concrete should be grounded in the first place. The proper way to ground the concrete is to utilize rebar. The method is popularly termed as the “Ufer Ground”. This concept has been recognized years before and has been standardized as well by NEC or National Electrical Code.
Rebar having direct contact with the earth is considered as the most critical element of it. Without direct interaction with the earth, the rebar might find it hard to ground the foundation. Any contractors must look at IEEE and NEC guidelines before starting to use the rebar to ground the concrete slab.
Different Types of Rebar
There are different types of rebar, and it depends on the kind of materials used in its production. Take a closer look below.
1. Carbon Steel Rebar
It is the type of rebar commonly made up of carbon steel and known as Black Bar due to its carbon color. The major drawback of this rebar is that it corrodes, which can adversely affect the structure and the concrete. The tensile strength ratio is usually coupled with the general value, making the black rebar one of the best picks, among others.
2. European Steel Rebar
Steel bars like this are made of manganese, and it makes them bend so easily. They are not preferable to use in some areas prone to extreme weather conditions and even geological effects where hurricanes and earthquakes are present. Apparently, this particular rebar’s cost is lower, and most buyers and contractors have found it as an advantage.
3. Epoxy-Coated Rebar
Epoxy-coated rebar is considered black rebar coated with epoxy. It has the usual standard tensile strength like other rebar but is 50 to 1500 times more resistant to corrosion. However, the epoxy coating of this rebar is very incredible and delicate — the more extensive the damage to the coating, the lesser resistance to corrosion.
4. Galvanized Rebar
This type of rebar is forty times more resistant to corrosion compare to black rebar. However, it is harder to damage the coating of this rebar. In that respect, this rebar is more valuable and preferable than epoxy-coated rebar. While it is forty times more resistant, this rebar is also 40% more expensive.
5. TMT Bars
TMT or Thermo Mechanically Treated Bars are a hot treated bar that is high in terms of strength. It is commonly used for RCC or reinforced cement concrete works. Today, the latest induction in the MS steel bars comprises superior properties like ductility, bending ability, welding ability, and highest quality standards globally. Here are some of the main characteristics of TMT rebar.
· High yield toughness and strength
· Earthquake and corrosion resistance
· Better malleability and ductility
· More bonding strength and higher thermal resistance
· No loss in strength at welded strengths
· Safe to use and very economical
· Ordinary electrodes are used whenever welding the joints
6. HSD Rebar
7.
High strength deformed rebar are twisted steel bars with projection, lugs, ribs, and deformations on the surface. During the construction, it is extensively used for reinforcement purposes. These bars are commonly produced in sections and sizes from 4 mm to 50 mm in diameter.
Here are the characteristics of HSD rebar:
· Superior bond strength
· Low carbon value
· High tensile strength
· Welding capability
· Wide application range
· Satisfactorily malleability
Why Must Concrete Contractors Invest in Project Management Software?
Operational excellence in today’s industry is vital. Hence, reliable and precise data is bound to make a huge difference on-site and team productivity. Industry leaders, business owners, project managers, and contractors have already understood the importance of investing in different technologies such as construction management software. Using a functional and cloud-based project management platform can help any construction businesses stand a chance to move in the right direction and work further towards the best possible outcomes.
Below are the outstanding benefits to discover in this application:
· Resources, crew and task management — managing tasks, tracking of time and labor hours, monitoring of resources and crew
· Document sharing and control– data storage, reporting, standardized document templates, sorting of all activities
· Real-time team collaboration and communication — shared calendar, task prioritization, team dashboard
· Cloud-based storage — accessible files anywhere and anytime, secure storage
Key Takeaways
Adding rebar to concrete has been proven to have many benefits. Rebar reinforcement helps reduce the breaking and cracking that is very common in concrete, but it has excellent brittle properties. Over the years, rebar provides extra concrete strength that has saved extra costs and additional concrete works.
