How to Add Glued Steel Fibres to Concrete

To add glued steel fibres to concrete, I recommend selecting the fibre dosage with the project engineer, weighing each batch accurately, introducing the fibres gradually, and mixing long enough to achieve uniform dispersion. Glued steel fibres are supplied in small bonded bundles that are designed to separate during mixing, which can help reduce fibre balling compared with loose fibres when the concrete mix is properly proportioned. The correct method still depends on fibre geometry, adhesive behavior, concrete workability, mixer type, and the structural design.

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In practice, I treat fibre addition as part of the complete mix-design process rather than as a simple substitution for conventional reinforcement. Before production, I confirm the required performance, fibre dimensions, dosage, batching sequence, and quality-control procedure. BEKA can support this evaluation by discussing application conditions, product specifications, trial mixing, packaging, and supply planning for glued steel fibres.

Why the Addition Process Matters

Steel fibres are used to improve the post-cracking behavior of concrete, including crack control, toughness, impact resistance, and resistance to localized damage. They do not automatically provide the same function as every type of bar or mesh reinforcement, so the structural designer must define where fibre reinforcement is suitable. The mixing process matters because an uneven fibre distribution can create weak zones, visible fibre clusters, or inconsistent finishing performance.

Glued fibres are manufactured with temporary bonding between individual filaments. During mixing, the bundles are progressively separated by the action of water, cement paste, aggregates, and mixer movement. This design can make fibre feeding more consistent, but it does not eliminate the need for correct aggregate grading, sufficient paste, controlled moisture, and adequate mixing energy.

Step-by-Step Process for Adding Glued Steel Fibres

1. Confirm the Design and Fibre Requirements

I begin by confirming the concrete application and the performance required from the fibre system. Typical applications may include industrial floors, precast elements, tunnel segments, shotcrete, pavements, slabs, and other reinforced concrete components. The design team should specify the required residual performance or other relevant acceptance criteria rather than choosing a dosage only by weight.

Next, I review fibre length, diameter, aspect ratio, tensile strength, surface profile, and glue-bundle configuration. A longer or higher-aspect-ratio fibre may provide different anchorage and mixing behavior from a shorter fibre, while hooked or deformed ends can affect pull-out resistance and finishing. As an initial trial-planning example, a project team may compare 20, 25, and 30 kg/m³, but these values are not universal recommendations and must be validated against the design and concrete mix.

2. Check the Concrete Mix Before Fibre Addition

The base mix should be reviewed before adding steel fibres. I check aggregate size and grading, cementitious material content, water content, admixture compatibility, target slump or flow, and the capacity of the mixer. A mix that is already harsh, dry, or poorly graded may not disperse fibres effectively, even when the fibre product itself is suitable.

I avoid adding extra water simply to recover workability after fibre addition. Additional water can change the designed water-to-cementitious-material ratio and may reduce the intended concrete performance. If more workability is required, the mix designer should evaluate an appropriate admixture adjustment and confirm the result through a trial batch.

3. Prepare Accurate Fibre Batches

Each fibre quantity should be weighed according to the approved mix design. For example, a 6 m³ batch at a selected dosage of 25 kg/m³ would require 150 kg of fibres; the project team should calculate the actual quantity from the approved dosage and batch volume. I recommend using calibrated scales and recording the fibre mass for every batch or defined production interval.

Packaging should remain dry and intact before use. If bags are damaged, contaminated, or exposed to moisture, I isolate them for inspection instead of automatically feeding them into production. The supplier should provide product identification, batch information, fibre dimensions, and handling instructions so that the material can be traced during quality control.

4. Add the Fibres in a Controlled Sequence

The correct addition sequence depends on the plant and mixer, so I first follow the fibre manufacturer’s technical guidance and the approved trial procedure. In many operations, coarse and fine aggregates are loaded with part of the mixing water, followed by cementitious materials and admixtures, while the fibres are introduced gradually rather than dumped as one dense mass. Gradual feeding allows the glued bundles to separate progressively and reduces the risk of localized fibre concentration.

For a ready-mix truck, fibres may be added through a controlled feeding system or manually in a managed sequence, depending on local procedures and safety requirements. I do not recommend throwing several unopened bags into a stationary mixer without checking the manufacturer’s instructions. The operator should also confirm that the mixer can safely receive and disperse the specified fibre quantity without exceeding its capacity.

5. Mix Until Dispersion Is Uniform

After the fibres enter the mixer, the concrete should continue mixing until the bundles have separated and the fibres appear reasonably distributed throughout the batch. A trial program may begin by evaluating an additional 30–60 seconds of mixing after fibre introduction, but this is only a starting point because mixer type, batch size, fibre dosage, and concrete consistency change the required time. The final mixing duration should be established through observation and trial testing, not copied blindly from another project.

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I inspect samples from different parts of the batch for fibre clumping, unusual fibre concentration, excessive bleeding, and changes in workability. A properly dispersed mix should not show large balls of fibres or obvious dry pockets. If clumping occurs, I review the feeding rate, aggregate moisture, paste volume, mixer loading, and sequence before increasing water or simply extending mixing time.

6. Place, Finish, and Cure the Concrete Correctly

Once the mix passes the dispersion check, placement should follow the project’s approved concrete procedure. Steel fibres can influence pumping, vibration, surface finishing, and the appearance of the finished surface, so the placing crew should understand the material before production begins. I pay particular attention to edges, joints, penetrations, and congested areas where fibre orientation and local distribution may differ.

Finishing equipment and timing should be selected through a trial where possible. Excessive surface working can draw fibres toward the surface or disturb the intended finish, while insufficient finishing may leave an unacceptable texture. Curing remains essential because fibre reinforcement does not remove the need to control early-age moisture loss and temperature-related cracking.

Key Decision Points During Trial Mixing

Common Mistakes to Avoid

Adding Fibres Without Rechecking the Mix

A common mistake is to add fibres to an existing concrete mix without considering paste volume and workability. Fibres increase the solid surface that must be coated by cement paste, and the mix may behave differently during pumping and finishing. I recommend a controlled trial before full-scale production, especially when the dosage, fibre geometry, or aggregate system is new.

Dumping All Bundles Into One Location

Rapidly feeding a large quantity of glued fibres into one point can overload the mixer and encourage clumping. I use a controlled feed rate and maintain a consistent flow of material. If automated feeding is unavailable, the site team should establish a safe manual method that follows the supplier’s handling instructions.

Changing Water Content Without Approval

Adding water on site may temporarily improve slump, but it can alter strength, durability, shrinkage, and finishing behavior. I first investigate aggregate moisture, admixture dosage, mixing time, and temperature. Any material change should be reviewed and recorded by the responsible concrete or structural professional.

Using Fibre Weight as the Only Acceptance Criterion

Correct mass does not prove correct dispersion or structural performance. I combine weighing records with visual inspection, fresh-concrete checks, production traceability, and any project-specific testing required by the design. Where residual strength or toughness is specified, the relevant test method and acceptance criteria should be agreed before production.

How to Optimize the Process

I recommend beginning with a representative trial batch using the actual aggregates, admixtures, mixer, fibre product, and production sequence. The team should record fibre dosage, batch size, mixing time, workability, discharge condition, finishing behavior, and any visible clumping. This creates a practical production window instead of relying on generic instructions.

Supplier communication is also important when the project has unusual requirements. BEKA can review the intended application, fibre dimensions, glued-bundle format, packaging, requested quantity, and delivery schedule before quotation. We can also help buyers identify the information needed for a technical comparison, while the project engineer remains responsible for structural design and final approval.

For larger orders, I suggest confirming monthly demand, batch quantities, packaging preferences, required documentation, inspection points, and shipping terms early. A clear purchase specification should state the fibre type, dimensions, nominal dosage, tolerance requirements where applicable, packaging, batch identification, and delivery destination. This reduces misunderstandings between the concrete producer, contractor, engineer, and supplier.

Summary and Next Steps

The reliable way to add glued steel fibres to concrete is to design the dosage first, prepare accurate fibre batches, feed the bundles gradually, mix until dispersion is uniform, and verify the result through a controlled trial. I do not treat fibre addition as a universal recipe because the correct process changes with fibre geometry, concrete composition, mixer equipment, and structural requirements. A practical trial may evaluate a dosage such as 25 kg/m³ and an additional 30–60 seconds of mixing, but these are project-specific starting points rather than fixed rules.

1. Define the required concrete performance and application.
2. Confirm fibre dimensions, bundle format, dosage, and packaging.
3. Run a representative trial with the intended production equipment.
4. Record dispersion, workability, finishing, and quality-control results.
5. Finalize the purchase and production specification before regular delivery.

If you are sourcing glued steel fibres for concrete production, contact BEKA with your application, estimated volume, required fibre specifications, batch size, destination, and target delivery schedule. I can help organize the technical and commercial information needed for a practical supplier evaluation and a controlled project start.

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