I once watched a new slab crack in weeks. I felt stuck. Choices looked messy. I now use a simple path. I match fiber to job, mix, and risk.

I choose fiber by goal first. I write the performance I need. I match it to a fiber family. I check standards, dosage, and supplier proof. I confirm finish, pump, and cost. I then lock the spec and test a batch.

I will guide you step by step. I will share the checks that saved my jobs. I will keep the steps clear. You can copy this today.

What job must the fiber do?

I once picked by habit and lost money. The slab curled and cracked. I now start with the job. I tie the choice to a clear, measured result.

I map problems to outcomes. I pick fibers that deliver that outcome. I define how we will measure it. I then test a small batch and confirm workability.

Common goals

I write the real goal in plain words. I do not start with a brand. I keep the list short and testable.

Quick match table

*I confirm dosage with the supplier test data for my mix and code path. I do not skip this step.

Which fiber type fits my mix and structure?

I once chose a strong fiber that would not pump. The crew fought the mix. I now check mix, placing, finish, and cover. The right pick must fit the method.

I list the fiber families. I note the pros and limits in plain words. I map them to my mix and crew tools. I then shortlist two options.

Fiber families at a glance

Fit with methods

• Pumping: I keep fibers under the limits the pump allows. I test with my supplier.
• Finishing: I plan the bull float and trowel timing. I keep trial panels on site.
• Cover and exposure: I check chloride class, freeze-thaw, and fire needs. I pick the safe fiber for the class.

How much fiber should I add and what length works?

I once used the right fiber and the wrong dose. The floor curled and joints failed. I now size by slab depth, panel size, and loads.

I start with the supplier design tables. I pick a length that matches slab depth and joint spacing. I pick a dose that meets the residual strength target. I always trial the mix.

Sizing and dosage rules I use

Length choice

Dosage starting points*

*I confirm with ASTM/EN test data and local codes.

Mixing and placing

• I add fibers slowly into a wet, moving mix.
• I extend mixing time as the supplier says.
• I watch slump and add superplasticizer, not water.
• I mock a panel and confirm finish and saw-cut window.

How do I prove performance and manage risk?

I once trusted a brochure and skipped tests. That job came back. I now prove the design on paper and on site. I make risk visible and shared.

I ask for test reports that match my mix and code path. I design the floor with residual strength, not hope. I run a site trial and record results. I keep photos and batches.

Design and test checklist

Paper checks

Design notes

• I set a residual strength target with my designer.
• I pick joint spacing and panel size that the fiber can carry.
• I model load cases for racking, wheel loads, and impact.
• I align saw-cut timing with finish plan.

Site controls

How do I balance cost and value?

I once bought the cheapest bag. The slab cost more later. I now count total cost, not price per kilo. I compare life and risk, not only strength.

I build a small scorecard. I weigh cost, performance, crew time, and warranty risk. I choose the best value, not the lowest tag. I share the math with my client.

My simple scorecard

I adjust the weights to fit the job. I write the reason for each score. I keep this with the spec.

Conclusion

I choose fiber by job, mix, and risk. I prove it on paper and on site. I then build with calm.