Reinforcing Fibers

KOREFIB^® MacroFibers G40

Composite macro fibers made of glass fibers for dispersed concrete reinforcement as an alternative to steel fibers and polymer fibers. They do not corrode and are dosed directly into the concrete mix.

Suitable for concrete and industrial floors, screeds, precast production and technical concrete elements. Manufactured in the Czech Republic, with a Building Technical Assessment and certification.

Dispersed reinforcement for concrete

KOREFIB^® MacroFibers G40 are composite fibers based on ECR glass fibers and an epoxy polymer matrix. They are used as dispersed reinforcement for concrete, screeds, floor slabs, precast elements and concrete components.

The fibers are dosed directly into the concrete mix. After mixing, they form a spatial reinforcement throughout the entire volume of the concrete and help limit the formation and development of cracks.

40 mmfiber length for concrete mixes

20,000 pcs/kghigh number of fibers per dose

1–7 kg/m³indicative dosage depending on application

KOREFIB MacroFibers G40 composite fibers for concrete

Concrete that doesn't fail once a crack appears

Ordinary concrete has high compressive strength but is brittle in tension. As soon as a crack forms, tensile load-bearing capacity is lost rapidly.

KOREFIB^® MacroFibers G40 help to limit this problem. After a crack forms, the fibers bridge its opening, transfer tensile stresses and improve the residual load-bearing capacity of the concrete.

help limit crack propagation,
increase the toughness of the concrete,
improve the behavior of the element after failure,
act throughout the entire volume of the concrete mix,
are not dependent on one specific position like a conventional mesh.

KOREFIB MacroFibers G40 dispersed reinforcement for concrete

How the fibers work in concrete

After being added to the mix, the fibers disperse evenly among the aggregate and cement matrix. Once the concrete hardens, they form a spatial network of randomly oriented reinforcing elements.

This network helps the concrete respond to tensile stresses arising from shrinkage, bending, point loading, impact or service loading.

The fibers do not automatically replace every type of steel reinforcement. For structurally significant structures, their use must be verified by calculation or by a designer's specification.

KOREFIB MacroFibers G40 fiber packaging for concrete

Where MacroFibers G40 make sense

The fibers are suitable wherever there is a need to limit cracking, improve concrete toughness and reduce the risk of problems associated with the corrosion of conventional reinforcement.

concretes, screeds and precast elements,
floor slabs on ground subgrade,
screeds over underfloor heating,
garages and technical spaces,
industrial floors with higher loading,
warehouses and operations with forklift traffic,
structures exposed to moisture, salts or chemical loading.

Use of KOREFIB MacroFibers G40 in a concrete mix

Main advantages of KOREFIB^® MacroFibers G40

Crack controlThe fibers help limit the formation and development of shrinkage and service cracks.

Residual strengthAfter a crack forms, they help transfer tensile stresses and improve the behavior of the concrete.

Non-corrosiveThe composite material is also suitable for moist, alkaline or chemically loaded environments.

Easy dosingThe fibers are added directly to the concrete mix without laying mesh or tying reinforcement.

Indicative dosage of KOREFIB^® G40

Dosage	Typical use	Purpose of use
1–3 kg/m³	Concretes, screeds, precast elements	Increased toughness, reduction of shrinkage cracks and improved overall behavior of the mix.
3–4 kg/m³	Floor slabs on ground subgrade, screeds over underfloor heating, garages, precast elements	Higher crack control, better distribution of tensile stresses and increased durability of normally loaded structures.
4–7 kg/m³	Floor slabs, industrial floors with high loading, warehouses, operations with forklift traffic	Higher residual strength after a crack forms and improved behavior of the concrete under service loading.

The dosage given is indicative. The exact amount must be determined according to the specific structure, concrete formulation, loading and the required function of the fibers.

Behavior of fiber-reinforced concrete under load

The graph shows the course of the loading force in relation to deformation for concretes with KOREFIB^® G40 fibers. What matters is not only the maximum force before a crack forms, but above all the behavior of the concrete after failure. It is precisely in this phase that the fibers help bridge the crack and improve the residual load-bearing capacity of the concrete.

Graph of loading force and deformation of concrete with KOREFIB G40 fibers

The graph is taken from the test documentation for concrete with G40 fibers. For design use, the specific concrete formulation, fiber dosage and the required residual strength values are decisive.

Dosage and design

The correct fiber dosage depends on the type of structure, the concrete class, the required function of the reinforcement, the loading and the required residual strength after a crack forms.

A different dosage is used to limit shrinkage cracks, another to increase toughness, and yet another for structures where the fibers are to fulfill a design or structural function.

to limit shrinkage cracks,
to increase the toughness of the concrete,
to improve behavior after a crack forms,
to partially replace conventional reinforcement,
for design use according to calculation.

For structurally significant structures, the use of the fibers must be verified by calculation, testing or a designer's assessment. The manufacturer bears no responsibility for the method of use or the results of the application.

Processing in the concrete mix

For the fibers to function correctly, their even dispersion in the concrete mix is important. It is advisable to add the fibers gradually and to ensure a sufficient mixing time.

For higher dosages, it is advisable to verify the workability of the mix with a trial batch and, if necessary, adjust the concrete formulation.

add the fibers gradually,
do not add the entire amount at once in one place,
ensure a sufficient mixing time,
check the consistency and workability of the mix,
for higher dosages, adjust the concrete formulation,
carry out a trial batch before series production.

Technical documents and tools

Detailed instructions, documentation and calculation tools for the composite fibers can be found in the technical section.

Fiber-reinforced concrete calculator Indicative design of an industrial fiber-reinforced concrete floor according to TR 34 and the recommended G40 dose. Launch calculator › How to dose the fibers A step-by-step guide to dosing and processing the fibers in the concrete mix. Open guide › Documentation for download Technical data sheets, certificate, Building Technical Assessment and catalog to download. View documents › Questions and answers Frequently asked questions about dosing, fiber function, certification and the behavior of fiber-reinforced concrete. View answers ›

Need a recommendation for the right dosage?

Send us the type of structure, the concrete thickness, the loading and the required function of the fibers. We will recommend a suitable procedure or prepare documents for assessment.

info@korefib.cz | +420 605 833 755

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KOREFIB® MacroFibers G40 Composite fibers for concrete

In stock

from 210 Kč / pcs

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1 items total

Reinforcing Fibers

KOREFIB® MacroFibers G40