Question

Question 1 (10 points). A sieve analysis was carried out on a sample of sand weighted 1 kg the following results were obtained. Find MNS of the sample, fineness modulus and draw grading curve. Weight of retained (g) Sieve Opening (mm) 38 19 9.5 4.76 2.4 1.2 0.6 0.3 0.15 123 242 294 212 100

Answer 1

MNS is the smallest sieve size through which all the aggreagte pass. hence MNS of the sample is 9.5 mm.

sieve opening (mm)	weight of retained(g)	cumulative weight retained(g)	%commulative weight retained
38	0	0	0
19	0	0	0
9.5	0	0	0
4.76	29	29	2.9
2.4	123	152	15.2
1.2	242	394	39.4
0.6	294	688	68.8
0.3	212	900	90
0.15	100	1000	100
			3.163

Therefore, fineness modulus of coarse aggregates = sum (cumulative % retained) / 100 = 3163/100=3.163.

Grading curve:

sieve size(mm)	percentage passing
38	100
19	100
9.5	100
4.76	97.1
2.4	84.8
1.2	60.6
0.6	31.2
0.3	10
0.15	0

grading curve percentage passing 0.2 0.4 0.6 0.8 1 2 4 6 8 10 20 sieve size(mm)