Micro Synthetic Fiber Dosage: How to Set a Trial Range

Micro synthetic fiber dosage should not be copied from an unrelated project. The suitable amount depends on the fiber product, intended function, cementitious system, aggregate grading, admixtures, mixing equipment, placing method and finish requirement.

Start Micro Synthetic Fiber Dosage with the Product Data

Use the current technical data sheet to establish an initial trial range. Confirm whether the recommendation applies to concrete, mortar, plaster or a dry-mix product. Fiber length, diameter and form can change handling even when two products use the same polymer.

The Micro Synthetic Fibers for Concrete selection page helps distinguish monofilament, fibrillated, ultra-fine and self-dispersing options before trials begin.

Check the Complete Mixture

Run controlled batches with a reference mix and record:

fiber addition sequence and mixing time;

visible dispersion or fiber balls;

workability, air content and unit weight where relevant;

pumping, placing and finishing observations;

the specified crack-control or durability test result.

Do not add water solely to recover workability. Any adjustment should remain within the approved mix-design process.

Define Acceptance Before Testing

A successful trial is not simply a mix that contains fibers. Acceptance criteria should reflect the project objective and applicable specification. ASTM C1116/C1116M provides a general framework for fiber-reinforced concrete, while a test such as ASTM C1579 may be considered when comparative plastic-shrinkage behavior is the question.

For a monofilament PP option, review HPM PP. For practical handling guidance, see How to Prevent Polypropylene Microfiber Clumping.

Final dosage must be approved by the responsible engineer or mix designer and supported by current product documentation and project trials.

Technical references: 

ASTM C1116/C1116M;

ASTM C1579;

current product TDS and project specification.