Problems that concern many construction professionals when it comes to concrete are the issues of shrinkage and cracking. Some contractors try to protect themselves from these issues by adding fibers to concrete. Should you use fiber-reinforced concrete? Here’s some useful information about fiber-reinforced concrete and the advantages and disadvantages of using it in your projects.
How Much Strength Does Fiber Add to Concrete?
In adding fiber to concrete, the goal is not to add strength, but to prevent cracking from drying shrinkage or plastic shrinkage.
While fibers added to concrete can give the concrete better impact resistance and tensile strength, they don’t necessarily make the concrete stronger with respect to flexural strength. Steel fibers can increase flexural strength to some extent, but other fibers generally will not — and they may even weaken your concrete slightly.
What Types of Fibers Are Used to Reinforce Concrete?
There are four categories of fiber that may be used to reinforce concrete, including:
If you’re using synthetic, fiber-reinforced concrete, your concrete may have either microfibers or macrofibers.
Microfibers are designed to minimize plastic shrinkage cracking. They’re typically made of nylon, polypropylene, polyethylene, polyester or acrylic, although other synthetic fibers are usable. Microfibers are typically found in the concrete used for driveways, sidewalks, curbs, garage and basement floors and other locations where you need a durable surface with minimal plastic shrinkage cracking.
Macrofibers are longer fibers that improve tensile strength as well as ductility. Their primary function is to provide an affordable alternative to rebar or welded-wire reinforcement. This type of fiber-reinforced concrete may be encountered in manholes, septic tanks and commercial flooring. It’s typically made from fiber that has similar characteristics to steel, such as polypropylene.
Advantages and Disadvantages of Fiber-Reinforced Concrete
As stated, the main advantage of fiber-reinforced concrete is the reduction of shrinkage and cracking. The right fiber-reinforced concrete can also provide impact-resistance, increase tensile strength and reduce voids in the concrete.
A disadvantage of fiber-reinforced concrete is that it can adversely affect workability, especially in the case of steel fiber-reinforced concrete. Even distribution of fibers throughout your concrete is a concern. There may also be a danger of fibers balling during mixing.
Another disadvantage to be aware of is that fiber-reinforced concrete is heavier than non-fiber concrete. If you’re using steel fibers, there’s also the danger of corrosion. Finally, fiber-reinforced concrete tends to be more expensive than ordinary concrete, although the cost could be offset by other factors.
Let Union Quarries Help You With Your Concrete Needs
If you’re not sure which type of concrete you want or you’re looking for a concrete supplier in central PA, Union Quarries is here for you. With over half a century of experience as a top concrete, stone and blacktop producer in central PA, we’re sure to be able to help you fulfill your project’s concrete requirements. To get a free quote, learn more about fiber-reinforced concrete or place an order, reach out to Union Quarries today.