Concrete looks strong and solid, but it is essentially a relatively brittle material. During the early stages after placement, moisture loss, plastic shrinkage, temperature changes and restraint from the substrate can create microcracks inside the concrete. As these cracks develop, they may eventually become visible cracking, surface damage or localized deterioration.

This is one of the main reasons PP Fiber (Polypropylene Fiber) is widely used in concrete and cement-based materials.

PP Fiber is not simply added to “increase concrete strength.” Its more important function is to form a uniformly distributed fiber network within the material, providing a bridging and restraining effect across developing microcracks. This helps control early shrinkage cracking while improving toughness and post-cracking performance.

Concrete undergoes shrinkage during the plastic and early hardening stages. When this shrinkage is restrained by the substrate, reinforcement or other structural conditions, tensile stress can develop and create microcracks that may not be visible at first.

When PP fibers are evenly distributed throughout the concrete, they form a fine three-dimensional reinforcement network. As cracks begin to develop, the fibers can provide a bridging effect across the crack and help restrict further crack propagation.

In simple terms, the main value of PP Fiber is:

This makes PP Fiber particularly useful in concrete, mortar and other cement-based materials where early crack resistance is important.

However, PP Fiber is not a standalone solution for every type of cracking. Mix design, substrate conditions, temperature, construction practices and curing also have a direct influence on final performance.

PP Fiber offers good chemical resistance and practical compatibility with cement-based materials, making it suitable for a wide range of applications.

In concrete floors, industrial facilities, warehouses, parking areas and general concrete construction, PP Fiber is mainly used to help control early shrinkage cracking and improve overall crack resistance.

In cement mortar, plastering mortar, repair mortar and crack-resistant mortar, PP Fiber can help reduce fine cracks caused by early shrinkage while improving overall toughness.

For selected precast concrete and cement-based products, PP Fiber can also be used as supplementary reinforcement to improve crack control during production and early curing.

Compared with steel fiber, PP Fiber is more commonly used for microcrack control and early crack resistance, rather than as a replacement for primary structural reinforcement.

The appropriate PP Fiber dosage depends on the concrete or mortar formulation, fiber specification, construction method and target performance.

For many general concrete applications, trial mixes can start around 0.6–1.0 kg/m³, followed by adjustment according to workability and actual crack-control performance.

The key is not simply increasing the dosage, but ensuring that the fibers are uniformly dispersed throughout the entire mix.

If PP fibers form bundles during mixing, even a sufficient total dosage may not deliver consistent performance. The feeding method and mixing time should therefore be properly controlled.

If workability or slump changes after adding fiber, simply adding more water is not always the right solution. It is better to optimize the overall formulation by considering the water-to-binder ratio, sand ratio, water-reducing admixture and fiber dispersion.

In other words:

For concrete and dry-mix manufacturers, selecting PP Fiber is not simply about price or dosage. Important factors include fiber consistency, dispersion, batch stability and compatibility with the existing formulation.

ARICH CELLULOSE® focuses on building additives and application solutions. Our portfolio includes not only PP Fiber, but also HPMC, MHEC/HEMC, RDP, PCE Powder, defoamers, retarders, starch ethers and other construction additives.

We look beyond the individual material and focus on how each additive performs within the complete formulation.

Based on the customer's concrete, mortar or dry-mix system, as well as the required construction conditions and performance targets, ARICH can support material selection, formulation matching and application optimization, helping customers achieve a practical balance between crack resistance, workability, consistency and cost.

PP Fiber does not simply make concrete “harder.”

Its real value is in forming a uniformly distributed fiber network that helps concrete better resist early shrinkage and microcrack propagation.

With the right PP Fiber, appropriate dosage, proper dispersion and a well-designed formulation, fiber can become an effective part of a concrete or cement-based crack-control system.