What is fibre-reinforced concrete?

Concrete is the most widely used building material on the planet, appearing in almost every type of structure. Because of its durability, strength, and extreme longevity, concrete is an essential building material. In addition, it can withstand compressive and tensile stress and harsh weather without compromising its architectural stability.
Concrete is used to construct many structures, including highways, bridges, parking structures, buildings, foundational surfaces, and many others. Many concrete structures are reinforced with steel rebar to increase their tensile strength and ability to withstand heavy loads. The compressive strength of concrete combined with the tensile strength of the reinforcement material improves the overall durability of the concrete. One type of reinforced concrete is fibre-reinforced concrete.
Fibre-reinforced concrete is a concrete mix that contains fibrous materials such as glass, synthetic or natural fibres. It is composed of cement, mortar, and discrete, short fibres distributed uniformly throughout the composite material.
Adding fibres to concrete reduces cracking and increases overall energy absorption and structural integrity. However, the fibres are not a substitute for stainless steel-reinforced concrete because they do not improve flexural strength or the ability of concrete to bend without breaking.

Types of fibre-reinforced concrete

Fibre reinforcement is used in both regular and shotcrete concrete. The most common type of steel fibre used in fibre-reinforced concrete is round-shaped steel fibres.
Steel fibre in concrete is frequently used for road pavement overlays, bridge decks, and airport pavement.
Glass fibres in concrete can create more modern and aesthetically pleasing, lighter structures, such as furniture or architectural cladding for buildings.
The synthetic fibre used in fibre-reinforced concrete is microfibres or macrofibres. Microfibres are commonly used in concrete to reduce shrinkage cracks and are acrylic, polyester, nylon, or polypropylene, among other materials. On the other hand, macrofibre is a more cost-effective reinforcement alternative to welded wire in concrete structures that require high tensile strength. As a result, microfibres are commonly used in constructing sidewalks, curbs, and driveways, whereas macrofibres are widely used to build septic tanks and manholes.

How fibre-reinforced concrete is made

Fibre-reinforced concrete can be made with either regular mixed concrete or mortar if the fibres are evenly distributed throughout. When mixing fibre-reinforced concrete, keeping the water-to-cement ratio and fibre size in mind is crucial. In addition, the percentage of fibre used in the concrete is also essential to consider because the volume of fibres used can affect the structure’s strength and sturdiness. When mixing fibre-reinforced concrete, it should be done uniformly without separation. Fibres must be added before mixing in the water to be evenly dispersed and not ball together.

Benefits of fibre-reinforced concrete

• Compared to using regular concrete or reinforcing the concrete with steel rebar, using fibre-reinforced concrete on a construction project has a few distinct advantages.
• Early crack detection and prevention. Fibres help control shrinkage cracking as the moisture level in the concrete mix changes as water evaporates. Fibre-reinforced concrete prevents or dramatically reduces early cracking from the start.
• Durability and toughness. When compared to unreinforced concrete, the addition of fibre increases the overall durability of the concrete, can help lower corrosion levels, cavitation damage, and has a higher level of tensile strength.
• Increased ductility. Fibre-reinforced concrete is less likely to be damaged by high tensile stress and can increase the weight that a structure can support, particularly when microfibres are used.
• A non-reinforced concrete alternative to rebar. Fibres can be used as an alternative reinforcement material to steel rebar or added to steel-reinforced concrete to reduce the amount of steel required, depending on the structure. This could also help to reduce the overall cost of the project.

Drawbacks of fibre-reinforced concrete

While there are numerous benefits to using fibre-reinforced concrete, the material also has drawbacks.
• It must be carefully mixed. Fibres used in fibre-reinforced concrete must be meticulously and uniformly dispersed throughout the concrete mix.
• Cost. Fibre-reinforced concrete is more expensive than non-reinforced concrete. However, most concrete is reinforced somehow, and many projects necessitate it.
• Weight. In general, adding fibres to concrete makes it heavier than plain concrete. This adds weight to the overall structure, so an engineer must account for it to maintain structural integrity.

Contact Eastern Readymix Tshwane for details

Eastern Readymix Tshwane offers ready-to-use standard and pumpable fibre-reinforced concrete designed for all general applications. Our standard and pumpable concrete mixes can be created and supplied to the clients’ specifications. In addition, fibre can be added to any standard or pump mix at an additional cost.
Contact one of our representatives today for more information about our fibre-reinforced concrete.