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Fineness Modulus Formula:
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The Fineness Modulus (FM) is an empirical figure obtained by adding the total percentage of material retained on each of a specified series of sieves and dividing by 100. It provides a numerical index of fineness of aggregates.
The calculator uses the Fineness Modulus formula:
Where:
Explanation: The formula calculates the average size of aggregate particles, with higher values indicating coarser aggregates and lower values indicating finer aggregates.
Details: Fineness Modulus is crucial in concrete mix design as it helps determine the proportion of fine and coarse aggregates needed to achieve desired workability and strength in concrete mixtures.
Tips: Enter cumulative percentage values separated by commas. The values should represent the percentages retained on standard sieves (typically 150μm, 300μm, 600μm, 1.18mm, 2.36mm, 4.75mm, and 10mm).
Q1: What is the typical range for Fineness Modulus?
A: For fine aggregates, FM typically ranges from 2.0 to 3.5. For coarse aggregates, FM ranges from 6.5 to 8.0.
Q2: How is Fineness Modulus used in concrete mix design?
A: FM helps determine the gradation of aggregates and ensures proper particle size distribution for optimal concrete strength and workability.
Q3: What are the standard sieves used for FM calculation?
A: Standard sieves include 150μm, 300μm, 600μm, 1.18mm, 2.36mm, 4.75mm, and 10mm sieves.
Q4: Can FM be used for both fine and coarse aggregates?
A: Yes, but the interpretation differs. Lower FM indicates finer material (suitable for fine aggregates), while higher FM indicates coarser material (suitable for coarse aggregates).
Q5: What are the limitations of Fineness Modulus?
A: FM doesn't provide information about particle shape or surface texture, and it may not fully represent the gradation curve's shape.