You probably already know rebar is steel embedded into concrete when it is poured to improve the concrete’s tensile strength. Rebar is made from recycled ferrous steel that’s been melted back down into either bars or continuous coils of various diameters.
Concrete performs especially well under compression forces (vehicles driving on a concrete driveway or road, for example), but it needs assistance to bear the weight of tension forces, such as weight in the middle of a beam that is supported on each end but not in the middle. Thus, the use of rebar.
Rebar comes in a variety of diameters. Rebar sizes in north America are based on an imperial measurement and based on 1/8 inch increments. For instance, #5 bar is 5 eighths of an inch in diameter (5/8”) . #4 bar is 4 – eighths of an inch or ½” in diameter. Below are the most common bar sizes used in North America with their metric equivalent.
#3 – 10mm
#7 – 22mm
#11 – 40mm
#6 – 20mm
#10 – 32mm
Using rebar helps with sustainable construction, as it is largely made from recycled materials. Rebar found in old construction can be pulled out and reused to make new reinforcing bars. Rebar can be recycled for an unlimited number of times. Organizations like The Steel Research institute estimate that more than 65% of all rebar ends up being recycled, minimizing waste production and the negative impact on the environment.
What is High Strength Rebar
Common rebar has a yield of 60,000 psi (60 ksi), or grade 60. High strength rebar has a higher yield to allow the use of fewer reinforcing bars in the structure. Yields for high strength rebar range from 75,000 psi to 100,000 psi or 75 ksi to 100 ksi.
High-strength rebar allows engineers to design structures to be built with 20% to 50% less steel that can result in up to 60% lower labor costs for rebar placing. By specifying high-strength steels, designers can solve costly rebar congestion problems and developers can complete structures more quickly, resulting in substantial cost savings.
Why should I care?
High strength rebar is a lot harder to cut and bend that Grade 60 rebar. It is a harder material that requires more force to cut and bend. If your cutting and bending equipment is not grade 100 ready, you may be replacing parts and having machines fail.
Make sure to consult with your rebar fabrication equipment manufacturer to make sure their machines can handle the added stress that this harder material subjects the machinery to. Harder materials may mean more frequent or regular preventative maintenance. Make sure your equipment manufacturer has a plan for your equipment and that its available to you. You also want to be sure you designate someone in your company who is responsible for making sure that maintenance gets done. Make sure they have a deep bench of service personal and spare parts to help minimize downtime due to additional wear.
Fewer bars in structures can also mean fewer bars being stored on your shop floor where space is often at a premium. Fewer bars can mean faster production times and fewer deliveries improving your margins.
High strength rebar is here to stay and being specified into projects more and more. Be sure you are Grade 100 ready.