How Concrete Fibers Prevent Cracks and Increase Durability

Concrete cracks easily. This is a common problem in many projects. Cracks can also make structures less durable. But there is a good solution. You can add Concrete Fibers to the concrete mix. These fibers work like tiny reinforcing bars inside the concrete. They help stop cracks from forming. They also help the structure last longer.

一. Three Key Functions of Concrete Fibers

Concrete fibers improve concrete performance in three ways: preventing cracks, enhancing strength, and increasing toughness.

1. Preventing the formation and propagation of cracks

This is the most direct function. When concrete is still in a plastic state, water evaporation can easily lead to shrinkage cracking. Fibers can form a supporting network internally to prevent this tensile stress.

After the concrete hardens, temperature changes or applied loads may also cause cracks. Highly elastic fibers (such as steel fibers) can effectively prevent these cracks, preventing them from widening and lengthening.

2. Enhancing the Mechanical Strength of Concrete

Adding concrete fibers can effectively improve the tensile, shear, and flexural strength of concrete. For example, incorporating a certain proportion of steel fibers， this can nearly double the tensile strength of concrete while reducing crack width by more than half.

This is particularly beneficial for structures subjected to flexural and tensile stresses, such as road slabs and industrial floors.

3. Imparts Better Toughness to Concrete

Ordinary concrete can break suddenly when it cracks. But if you add concrete fibers into concrete， it will be different. Even after cracks form, the fibers that bridge the crack can still carry pulling forces.

This helps the structure bend without breaking and resist impacts better. That’s why it is important for buildings in earthquake-prone areas.

二. A comparison table of concrete fiber selections, clearly showing the best choice for different scenarios:

1. Selection by Strength Grade

C30: Ordinary building foundations, high cost-effectiveness

C40: Medium load-bearing structures, balancing performance and cost

C50: Highrise/largespan buildings, requiring highductility fibers

2. Comparison by Concrete Fiber Type

三. How to Choose the Right Concrete Fiber for Your Project?

Choosing the right concrete fiber is very important. It’s just like selecting the right “equipment” for a project; it requires considering the project type, specific needs, and budget.

Step 1: Select Based on Project Type

High-rise buildings, bridges, and long-span structures: Steel fiber or fiberglass is recommended. They offer strong crack and impact resistance, providing additional safety for critical load-bearing structures.

Ordinary residential buildings, floors, and pavements: Polypropylene fiber is a cost-effective option. It effectively inhibits plastic shrinkage cracks at a relatively low cost.

Special corrosive or high-temperature environments: The chemical stability of the fiber needs to be considered. Acid and alkali resistant synthetic fibers or specially coated steel fibers may be more suitable.

Step 2: Selection Based on Core Performance Requirements

Main Goal: Control Cracks
Fibers with high elastic modulus, such as steel or glass fibers, should be selected, as they offer more direct restraint.
Main Goal: Improve Toughness and Impact Resistance
    Polyacrylonitrile fibers can be considered, or a mixture of different fibers (such as a composite of steel and polyacrylonitrile fibers) can be used to achieve optimal overall performance.
Main Goal: For projects with extreme durability requirements
    For very cold areas: The fiber must handle freezing and thawing well. Some synthetic fibers are good at this.  
    For corrosive environments: The fiber must be tough. It should not rust or break down easily in chemicals.

Step 3: Comprehensive Consideration of Budget and Construction Conditions

Prioritize Cost Control: Polypropylene fibers are generally more cost-effective, they suitable for large areas or budget-sensitive projects.e areas or budget-sensitive projects.
Pursue Ultimate Performance: Although high performance fibers such as steel fibers and carbon fibers have higher unit prices, but the resulting strength improvements are significant, potentially leading to a higher overall value.
Consider Ease of Construction: The uniform dispersion of fibers in concrete is crucial.
For pumped or self-compacting concrete, choose fiber products with good dispersibility to avoid clumping.

ABOUT RBOSCHCO

Choosing the right concrete fiber is only the first step; finding a reliable partner is crucial to ensuring the final result. RBOSCHCO focuses on the research, development, and production of high-performance concrete reinforcement materials. We offer a variety of concrete fiber products, including steel fibers, synthetic fibers, and specialty fibers.

Our goal is not just to sell products, but to provide solutions. RBOSCHCO’s technical team can provide selection advice and offer professional application guidance， which is based on your specific materials and construction processes. If you face challenges in preventing concrete cracking or improving durability, please get in touch with RBOSCHCO; we will work with you to find the best solution.