Properties of Steel Fiber

Steel fibers are filaments of wire, which is deformed and cut into pieces, for reinforcement of concrete, mortar, and. Addition of steel fibers to concrete actually transforms a relatively brittle material into a ductile one. The key factors that decide the proportions of steel fibers in the mix design depend upon the physical properties required in the project. Therefore, it is important to look at the few steel fiber properties:

• Steel fibers are evenly distributed throughout a given cross section. However, reinforcing bars or wires are provided only according to their requirement.
• Steel fibers are relatively short. Small fibers tend to have greater control of cracks. This is an important consideration in designing the mix.
• Steel fibers are typically added to concrete in low volume dosage. The dosage is often as low as 1%. But, it has been proved to be effective in reducing plastic shrinkage cracking.
• The distribution of steel fiber reinforcement is provided by the higher fiber count in terms of the number of fiber per kilogram. Therefore, greater crack control during the drying process.
• It is true that steel fibers typically do not alter shrinkage of concrete significantly. Heavily deformed fibers provide better post-crack strength because high dosages of steel fibers increase the resistance to cracking. It may also decrease the crack width.
• When steel fibers are added to mortar, Portland cement concrete or refractory concrete, its flexural strength increases. The increase may depend upon the proportion of fibers added and the mix design.
• Any material or structural component that is used in construction must have the ability to withstand load without breaking or bending. This includes its own weight and the carrying capacity for which it has been designed. Failure to do so is often referred as a catastrophic failure. Catastrophic failure of concrete usually occurs when a material is stressed beyond its limit. Such excessive deformations can be eliminated by the steel fibers continue supporting the load after cracking occurs.
• Further, steel fiber reinforced concrete provides better and improved fatigue strength.
• Fabrics do very little in order to reinforce the outer zones. It is because of this reason that the spalling occurs in the joints and edges. Spalling is the process in which cracks enlarge and force concrete to fracture apart. It is widely known as concrete cancer. Higher resistance to spalling is provided by the use of steel fibers.

It is a well-known fact that concrete is very good in resisting compressive forces. Despite this, it is found to be week against the tensile forces. Addition of steel fibers in Portland cement is very effective in resisting flexural tensile stresses. All the steel fiber properties listed above have contributed to the extensive use of steel fiber in tough and durable structures. This further helps to reduce maintenance and repair cost.

Many concrete structures from the last century are crumbling. These include; bridges, highways, and the buildings. Many of these structures were built using concrete and will turn out to be obsolete before its end.  There are serious environmental costs involved in rebuilding. Concrete is the third-largest contributor to carbon dioxide emissions in the world. It also amounts to a large proportion of construction and demolition waste, that further contributes to the filling of landfill sites. Recycling of concrete is further difficult, expensive, and reduces its strength. Therefore, there is a need for low-cost alternative, which provides strength to the structure and makes them long-lasting.

Steel is often perceived to be inert and resilient because of the rust. If the construction steel is visible, it requires maintenance. For instance, the Sydney Harbour Bridge is repeatedly painted to avoid rusting conditions. However, steel when mixed in concrete, steel may not rust if there are no cracks. We at Precision Drawell Pvt. Ltd. believe that steel is hidden and secretly active. Moisture entering through tiny cracks may lead to rusting. However, it still takes a long time to rust than the steel used visibly on the structures.