What is the flatness index and why is it important?
The flatness index indicates how many flat particles are present in a stone mixture. This is an important indicator of the quality and strength of foundation materials. Too many flat pieces can lead to reduced stability and even fracture in the foundation. By determining the flatness index, you know if your material is suitable for application.
The test is carried out according to the NEN-EN 933-3 standard, so you can rely on reliable and standardized results.
How we determine the flatness index accurately
For a correct measurement, we first determine the grain distribution of the material. We then analyze only the relevant fractions between 4 mm and 80 mm. Using bar screens, we measure which particles have a specific length-to-thickness ratio. Flat pieces fall through the sieves in this process.
For each sieve component, we determine the percentage of flat particles. At the end of the test we calculate the total percentage for the entire sample.
Our expertise in civil engineering materials testing
Normec specializes in civil engineering and environmental laboratory testing. We combine experience with accurate measurement methods and accredited practices.
You can count on:
- Reliable and reproducible analyses
- Execution according to recognized standards
- Clear and practical reports
What does this mean concretely for you?
- You gain insight into the shape of the grains in your material
- You prevent risks of fractures in foundations
- You support material choices with reliable measurement data
- You meet technical requirements and standards
- You increase the safety and durability of constructions
Strong and reliable foundations
A good understanding of the shape and quality of material particles is essential for sustainable structures. With the flatness index, you prevent problems and improve performance. We support you with reliable analyses and clear insights. So you can continue building with confidence.
Would you like to know more about the flatness index?
Frequently Asked Questions
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The flatness index represents the percentage of flat particles in a stone mixture.
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Because flat particles can reduce the stability of a foundation and cause fracture.
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The flatness index is determined according to NEN-EN 933-3.
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Only grain sizes between 4 mm and 80 mm are included in the analysis.
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Using rod screens, flat particles are separated and determined by fraction.
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You will receive a clear report with the total percentage of flat particles.