The fineness modulus (FM) of aggregate is a numerical index that measures the coarseness or fineness of the particles. It is calculated by adding the cumulative percentages of aggregate retained on each of a specified series of sieves and dividing the sum by 100.
Consider performing sieve analysis on sand through a set of ASTM sieves. The weight of aggregate retained in each sieve and pan placed at the bottom is recorded, as given in Column B of Table 1.
To determine the fineness modulus of sand, calculate the cumulative weight of aggregate retained on each sieve (Column C of Table 1) and express it as a percentage of the total weight (Column D of Table 1). Finally, the sum of the cumulative percentages of aggregate retained on each sieve is determined and multiplied by 100 to obtain the fineness modulus of the sand.
Table 1: Sieve analysis on sand
Column A | Column B | Column C | Column D |
ASTM Sieve | Weight retainedon each sieve (g) | Cumulative weightretained on each sieve (g) | Cumulative percentage retained on each sieve (%) |
⅜ inch |
0 | 0 | 0 |
No. 4 | 5 | 0+5 = 5 | 5/500 = 1 |
No. 8 | 55 | 5+55 = 60 | 60/500 = 12 |
No. 16 | 65 | 60+65 = 125 | 125/500 = 25 |
No. 30 | 90 | 125+90 = 215 | 215/500 = 43 |
No. 50 | 160 | 215+160 = 375 | 375/500 = 75 |
No. 100 | 90 | 375+90 = 465 | 465/500 = 93 |
Bottom pan | 35 | Total weight = 465+35 = 500 |
In general, sand has a fineness modulus of around 2.3 to 3.1. Lower values indicate finer sand, while higher values mean the sand is more coarse.
From Chapter 5:
Now Playing
Aggregates and Water
125 Views
Aggregates and Water
69 Views
Aggregates and Water
112 Views
Aggregates and Water
178 Views
Aggregates and Water
221 Views
Aggregates and Water
41 Views
Aggregates and Water
58 Views
Aggregates and Water
75 Views
Aggregates and Water
272 Views
Aggregates and Water
141 Views
Aggregates and Water
106 Views
Aggregates and Water
179 Views
Aggregates and Water
141 Views
Aggregates and Water
334 Views
Aggregates and Water
197 Views
See More
Copyright © 2025 MyJoVE Corporation. All rights reserved