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Clinical Pharmacy-Pharm D Level Three 2 Semester 2024/2025 Pharmaceutical Technology (PT 607)

Fineness modulus (FM)

The Fineness modulus (FM) is an empirical figure obtained by adding the total

percentage of the sample of an aggregate retained on each specified series of
sieves and dividing the sum by 100.
1. Smaller value that range from a FM of 2.00 to 4.00 indicates a finer

aggregate.
2. Coarse aggregates range from 6.50 to 8.00.
3. Combinations of fine and coarse aggregates have intermediate values

(more than 4 and less than 8).
Fineness modulus = Ʃ cumulative % retained / 100

Determine Fineness modulus of the following particles:

Med point of Frequency
size range (n)

3.7 5
3.2 8
2.7 17
2.2 54

1.7 22
1.2 10
0.7 2
solution

Med point of size range Frequency Percent % Cumulative % over size
(n)

3.7 5 4.32 4.32
3.2 8 6.79 11.02
2.7 17 14.41 25.43
2.2 54 45.76 71.19
1.7 22 18.64 89.82
1.2 10 8.47 98.3
0.7 2 1.7 100
Ʃ= 118 Ʃ= 399.99

Fineness modulus

= Cumulative % over size, or Cumulative %retained/100 =400/100
= 4
Hence, the particles are fine aggregates.

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