If we were to say that concrete is the most popular and common building material in the world, there wouldn’t be any argument. Concrete is the most used material in the world, second only to water.
Fiber Reinforced Concrete is among the many innovations developed to improve strength characteristics and other properties of concrete.
In this article, we will examine fiber reinforced concrete, what this concrete is, its different types, and benefits, and find out if this concrete mix is right for you.
What is Fiber Reinforced Concrete?
Fiber-reinforced concrete (FRC) is fresh concrete reinforced with fibrous materials. For example, long steel fibers. This method of reinforcement improves the properties of normal concrete.
Many different fibrous materials are used to make fiber-reinforced concrete. This kind of reinforced concrete has become so popular that various versions of fiber reinforced concrete are produced based on application requirements.
What Is Fiber Reinforced Concrete Made of?
The main ingredients of fiber-reinforced concrete are:
The main component of fiber-reinforced concrete is hydraulic cement, which becomes adhesive after reacting with water. Commonly, Portland cement is used as the hydraulic cement in fiber-reinforced concrete.
Adding long fibers alters the properties of the fresh concrete based on the kind of fibrous material used. There are four categories of fibers generally used in producing fiber-reinforced concrete. These concrete fibers are:
- Steel fibers
- Glass fibers
- Synthetic fibers
- Natural fibers
An aggregate provides the binding strength in concrete while reducing the volume of cement required. Some common aggregates are sand, crushed stone, and gravel.
Brief History of FRC
FRC has been around for a long time, but the concrete fibers have been improved. In earlier times, when buildings were constructed using stones, mortar acted as the bonding agent holding them together. The mortar was reinforced using horsehair.
Similarly, in the case of mud-brick construction, straw was the primary reinforcement material. When concrete became one of the most common building materials, asbestos fibers were used as reinforcement.
However, as the decades progressed, people became more aware of the health risks of asbestos and how it causes cancer. During the 1960s, instead of asbestos, other fibers like steel and glass gained popularity.
What is the Effect of Fibers in Concrete?
Adding fibers to concrete results in several effects. The magnitude of these varies based on the specific fibers used. The improvement in load-bearing capacity depends on various factors, such as the number of reinforcing fibers in relation to the overall volume, termed the volume fraction, and the aspect ratio, obtained by dividing fiber length by the diameter of the fiber in question.
Fibers generally serve the primary purpose of reducing cracking in the concrete by improving its flexural strength. Cracking in concrete occurs because of concrete shrinkage. Concrete shrinkage can happen for multiple reasons, such as drying shrinkage and plastic shrinkage.
Also, fibers lower the permeability of concrete, eliminating the possibility of water leaking through concrete structures.
What are the Different Types of Fiber Reinforced Concrete?
There are various types of fiber-reinforced concrete composites in popular applications. Some of these include:
Steel Fiber Reinforced Concrete
Steel fiber reinforced concrete is one of the most widespread types of FRC. Adding reinforcing steel fibers to the concrete, even in small amounts, leads to significant improvements in the properties of the concrete.
Steel fiber reinforced concrete is used in applications with heavy-duty concrete requirements such as bridges, floors, tunnels, mining, precasts, etc.
There are many different kinds of steel fibers used to reinforce concrete, such as cold drawn wire (Type 1), cut sheet steel fibers (Type 2), melt extracted (Type 3), mill cut (Type 4), and modified cold drawn wire (Type 5).
Polypropylene Fiber Reinforced Concrete (PFRC)
PFRC uses synthetic fibers called Polypropylene fibers, a type of thermoplastic. There are many different benefits of adding polypropylene to concrete, which we will discuss in the next section.
Polypropylene shares many characteristics with polythene, with improved hardened properties, flexural strength, and higher heat resistance.
Additionally, this fiber has a high resistance against chemicals like acids and organic solvents, and it imparts similar properties to the concrete.
Glass Fiber Reinforced Concrete (GFRC)
A glass fiber reinforced concrete mix includes many small glass particles. How do these make the concrete stronger?
While a large glass pane is delicate, glass fiber has very high structural strength. In addition to this strength, the fibers are a low-cost additive, making the final concrete mix cheaper than alternatives like steel fiber reinforced concrete.
The same fibers added to plastic result in a fiberglass composite material with excellent tensile strength properties.
Polyester Fiber Reinforced Concrete
Polyester fibers for fiber reinforced concrete are available as microfibers and macro fibers. Polyester fibers contribute to the improved cracking resistance of this type of fiber-reinforced concrete.
Polyester fiber reinforced concrete has greater toughness and higher structural integrity. Its enhanced durability makes this type of concrete ideal for industrial flooring, warehouse flooring, precast structures, overlays, and similar commercial applications.
Carbon Fiber Reinforced Concrete
Have you ever heard of carbon fiber steel? The concept is similar for carbon fiber reinforced concrete.
While adding carbon fiber to concrete is a more complex process than adding cement or glass, the resulting concrete has high rigidity and strength. However, with high rigidity, the concrete becomes more brittle (like carbon steel).
Macro Synthetic Fiber Reinforced Concrete
Using macro synthetic fibers in concrete came about as an alternative to steel reinforcement. After all, steel reinforcement can be a costly addition to concrete.
With growing use, macro synthetic fibers became more than just an alternative. These fibers have many applications of their own, especially in ground-supported structures.
Steel reinforcement may corrode in areas with high humidity, such as marine environments, and glass fibers suffer from the risk of spalling. Macro synthetic fibers offer high resistance to these factors, so they are a valuable addition to concrete in these environments.
Natural Fiber Reinforced Concrete
Natural fibers come from plants, animals, and natural minerals. As we mentioned in the section about the history of FRC, natural fibers have been used in the construction process since ancient times.
No matter where the concrete is used, there will be an abundance of natural fibers present. These fibers also help in lowering the cost of manufacturing FRC.
Some natural fibers include cotton, straw, wood, and grains.
What are the Benefits of Using Fiber Reinforced Concrete
Adding different fibers to concrete results in various benefits. Fiber-reinforced concrete is classified based on the fiber added. The specific benefits of FRC will depend on the type of FRC used.
In general, here are the benefits associated with some common types of fiber-reinforced concrete:
Glass Fiber Reinforcement
- Glass fiber reinforcement increases the structural strength of the concrete without increasing costs significantly. Glass is one of the cheapest fiber materials.
- This type of reinforcement is used to enhance the aesthetic appeal of the concrete structure. The short discrete fibers can be seen in the concrete structure after it dries.
- This reinforcement method adds tensile strength to all the areas, unlike traditional reinforcement using steel bars, where the tensile strength is limited to the direction of the bars.
Steel Fiber Reinforcement
- Steel provides the highest structural strength in fiber reinforced concrete.
- With the addition of steel fibers, the concrete requires fewer steel bar reinforcements.
- Fibers produce greater impact resistance against impacts and abrasions.
- Improved thaw resistance and other temperature characteristics of the building.
- Mitigates the risk of cracking by reducing the width of the cracks.
Polypropylene Fibers and Nylon Concrete Reinforcement
- Provides the ability to pump the concrete over a long distance by increasing cohesion properties.
- Improves temperature characteristics (e.g., thaw resistance).
- Enhances the ductility of concrete and reduces its brittle nature.
- In the event of a fire, concrete structures with polypropylene fibers and nylon fibers are resistant to explosive spalling.
- Results in high impact resistance and abrasion resistance.
What Are the Applications of Fiber Reinforced Concrete?
The type of FRC used can vary based on the particular construction project. In general, most civil engineering projects utilize FRC. For example::
- Concrete pipes
- Warehouse floors
How to Source Fiber Reinforced Concrete?
As you know by now, fiber-reinforced concrete isn’t just one product. There are varying concretes with different reinforcement techniques resulting in specific enhanced properties.
There are high-strength steel fibers that amplify the structural integrity of the concrete manifold. Also, glass and synthetic fibrous materials offer moderate strength but at a cheaper cost.
Regardless, the FRC you specify for your project should come from a reliable supplier, with details on the specific fibers added to concrete.
Premier Precast is one of the most popular award-winning FRC suppliers in the US, accredited by the American Concrete Institute. With a wide range of FRC mixes, we add high-quality fiber and carry out the mixing ourselves.
Many popular commercial and residential projects have already used the FRC provided by Premier Precast. Besides fiber reinforced concrete, there are also many other concrete lines that we offer.
Therefore, if you are looking for the best quality FRC for your project, Premier Precast is the concrete supplier you should consider.
Call us today: (561) 330-3737