1. What is Fineness Modulus?

Fineness Modulus (FM) is an empirical figure obtained by adding the total percentage of material in a sample of aggregate that is coarser than each of a series of sieves and dividing the sum by 100. It provides a measure of the fineness or coarseness of aggregate materials.

2. How Does the Calculator Work?

The calculator uses the Fineness Modulus formula:

Where:

• \( FM \) — Fineness Modulus (unitless)
• \( \sum CP \) — Sum of cumulative percentages retained on standard sieves (%)

Explanation: The formula calculates the average size of aggregate particles, with higher values indicating coarser aggregates and lower values indicating finer aggregates.

3. Importance of Fineness Modulus

Details: Fineness Modulus is crucial in concrete mix design as it helps determine the proportion of fine and coarse aggregates needed to achieve the desired workability and strength in concrete.

4. Using the Calculator

Tips: Enter the cumulative percentage value (%). The value must be a positive number greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for Fineness Modulus?
A: For fine aggregates, FM typically ranges from 2.0 to 4.0, with higher values indicating coarser sand.

Q2: How is cumulative percentage calculated?
A: Cumulative percentage is obtained by adding the percentage of material retained on each sieve and all sieves above it.

Q3: Why is Fineness Modulus important in concrete mix design?
A: FM helps in determining the gradation of aggregates which affects the workability, strength, and durability of concrete.

Q4: Can FM be used for both fine and coarse aggregates?
A: While primarily used for fine aggregates, the concept can be applied to coarse aggregates with appropriate sieve sizes.

Q5: What are the limitations of Fineness Modulus?
A: FM doesn't provide information about particle distribution and may give the same value for different gradation curves.