What is Steel Fiber Concrete? Uses and Applications
Steel fiber concrete flooring can provide superior resistance to minimize cracks in hardened concrete, as well as maximum resistance to withstand heavy loads, either dynamic or static. If you decide to use steel fiber concrete flooring, you can select to use a ‘joint-less floor’. Joint-less floors are floors that have minimal joints, providing spaces without joints as large as 40 or 50-meter span wide.
Steel fiber dosage will vary greatly upon the project intended use, and the types of mesh being replaced. Common dosages are in the range between 20-30kg/m3 to 40-50kg/m3 for joint-less floors. Trowelling concrete will help to embed steel fibers into the concrete surface producing a better finish product. Steel fibers will enhance to crack resistance of the concrete, and they can also be used to replace or supplement structural reinforcement. It only can be done through a structural engineer and with proper guidance.
How and When the Fiber is Added
Typically the fibers are added at the batch plant, just after all concrete aggregates are being mixed. Some people would request to have the fiber added at the job site, but then the QA/QC should have more control on how much fiber is added. The steel fiber manufacturer can provide guidance on how to mix and the amount needed to obtain the desired results. Be aware that if you add too much fiber, it might show up at the surface when finishing the concrete so be cautious about the amounts being mixed.
Costs of Steel Fiber Concrete Flooring
In general, and depending on the type of steel fiber used, it can add between $6 to $10 per cubic yard on top of the ready-mix concrete cost. This cost is based on the assumption that you are using 1.5 pounds per cubic yard of concrete.
How Workability is Affected
If you opt-in to add fiber to your concrete mix, be aware that there will be some changes in the way you manage this concrete. First of all, the slump will be affected, and it is recommended to add a superplasticizer to enhance the slump and make the concrete a little more fluid. Not all steel fiber can be used as a substitute for steel reinforcement, so make sure that your structural engineer has reviewed and analyzed the loads before proceeding.
Where to Use Steel Fiber Concrete Floors
Typical applications for steel fiber concrete flooring can be found on parking lots, playgrounds, airport runways, taxiways, maintenance hangars, access roads, and workshops. This method is also widely used for port pavements, container storage and handling areas, bulk storage warehouses and military warehouses. Steel fiber reinforced concrete is commonly used in tunnel construction, as it provides additional flexural strength, reduces shrinkage cracking and reduces permeability.
Advantages of Steel Fibers in Concrete
Several advantages can be obtained from this product, for example:
- Increased load-bearing capacity of concrete
- Reduction of concrete slab thickness
- Load capacity is not diminished by concrete cracks
- Increased durability
- Low maintenance costs
- Improved flexural properties
- Reduced absorption of water, chemicals, etc.
- Can be used on fast track schedule
- Easier positioning of joints
- Reduced site labor for managing steel reinforcement
- Reduced project costs
- Increased impact and abrasion resistance
- Even distribution of fibers throughout the concrete
- Tougher surface with fewer bleed holes
- Savings will be greater for heavier crack control systems