Example for fineness modulus of Sand Calculation

 

Example for fineness modulus of Sand Calculation

Let us say the dry weight of sample = 1000gm

After sieve analysis the values appeared are tabulated below.

Sieve size	Weight retained (g)	Cumulative weight retained(g)	Cumulative percentage weight Retained (%)
4.75mm	0	0	0
2.36mm	100	100	10
1.18mm	250	350	35
0.6mm	350	700	70
0.3mm	200	900	90
0.15mm	100	1000	100
Total			275

Therefore, fineness modulus of aggregate =? (cumulative % retained) / 100 = (275/100) = 2.75

Fineness modulus of fine aggregate is 2.75. It means the average value of aggregate is in between the 2^nd sieve and 3^rd sieve. It means the average aggregate size is in between 0.3mm to 0.6mm as shown in below figure.

Limits of Fineness Modulus for Fine Aggregate

Fineness modulus of fine aggregate varies from 2.0 to 3.5mm. Fine aggregate having fineness modulus more than 3.2 should not considered as fine aggregate. Various values of fineness modulus for different sands are detailed below.

Type of sand	Fineness modulus range
Fine sand	2.2 – 2.6
Medium sand	2.6 – 2.9
Coarse sand	2.9 – 3.2

Fineness modulus limits for various zones of sand according to IS 383-1970 are tabulated below.

Sieve size	Zone-1	Zone-2	Zone-3	Zone-4
10mm	100	100	100	100
4.75mm	90-100	90-100	90-100	95-100
2.36mm	60-95	75-100	85-100	95-100
1.18mm	30-70	55-90	75-100	90-100
0.6mm	15-34	35-59	60-79	80-100
0.3mm	5-20	8-30	12-40	15-50
0.15mm	0-10	0-10	0-10	0-15
Fineness modulus	4.0-2.71	3.37-2.1	2.78-1.71	2.25-1.35

Read More: Fineness Modulus of Coarse Aggregates and its Calculation