Fiber reinforced concrete is Portland cement concrete that has been strengthened with fibers that are more or less randomly positioned. During the mixing process for fiber reinforced concrete, hundreds of tiny fibers are spread and distributed randomly throughout the mixture, increasing the qualities of the concrete in all directions. The pre-crack tensile strength, post-peak ductility performance, fatigue strength, impact strength, and reduction of thermal and shrinkage cracks are all enhanced by fibers.
This is accomplished by utilizing natural, metallic (steel), synthetic (polymers), and mineral (carbon or glass) fibers. Due to the plastic retraction and drying processes, which also decrease its permeability, they prevent cracks in the concrete from forming. The fibers running through the structure form structural micro-reinforcements that stop fissures from expanding when it is subjected to high tension due to external loads, changes in temperature, or humidity. Overall, fiber reinforced concrete greatly enhances the performance of mortars and concretes under traction and shear stress, which are often characterized by low resistance.
What is concrete reinforced with fibers?
In concrete floor construction, fiber-reinforced concrete is an alternative to steel mesh reinforcement. Steel fibers are added to the concrete mixture prior to pumping it onto the substructure and pouring the concrete floor.
When certain composite metal deck profiles are chosen, steel fiber reinforcement can substitute mesh reinforcement in composite floor construction. When Kingspan Multideck steel decking is specified, MD50-V3, MD60-V2, or MD80-V2 profiles of steel fiber reinforced concrete can be employed.
Off-site preparation of concrete reinforced with steel fibers to a predetermined dosage is possible. Additionally, it can be used to make concrete hardstandings and industrial concrete floors.
There are numerous advantages of utilizing steel fiber as reinforcement for concrete floors:
- Eliminates the need for raising and inserting netting.
- Reduces labor time and, thus, programme duration (on some projects by as much as two days per concrete pour)
- Particularly advantageous on high-rise constructions and sites in tight regions, as well as sites with limited material storage space.
- With greater shrinkage control and fewer cracks, the concrete’s performance is significantly enhanced.
- Maintains a same degree of reinforcement throughout the whole concrete floor structure
Why are reinforced concrete floors necessary?
As a building material, concrete is strong in compression but weak in tension. Unless reinforced, concrete exposed to high traffic, huge loads, and even dramatic temperature changes can crack, deform, become brittle, and lose its structural integrity.
Advantages of reinforced concrete floors
By reinforcing a concrete floor, its durability, strength, fire resistance, and load-bearing capacity can be enhanced, as can its lifetime.
- Help prevent cracking in concrete floor slabs (some cracking is inevitable)
- Permit uniform pressure distribution from weights applied to the concrete slab (tensile stress is transferred to the steel rebar)
- Enhance the fire resistance of the concrete floor (steel and concrete react to changes in temperature in the same way, therefore reducing internal stresses)
- Permit the construction of a concrete floor slab with a reduced thickness.
- Steel fibre reinforcement versus mesh reinforcement
- Steel fibre reinforced concrete is faster to install than mesh reinforcement, and there is no need to store rebar on-site or lift it to the needed storey for installation.
Typically, steel fibres provide an even distribution of reinforcement across the entire concrete slab, which enhances its flexural strength and fracture resistance and imparts a stronger impact resistance to the surface of the concrete.
Since neither mesh nor fibre reinforcing can prevent the formation of fractures in a concrete slab, control joints should be integrated into the slab. If an unexpected crack develops, steel mesh reinforcement is more effective than fibre reinforcement at containing the crack and preventing it from spreading.