Civil Engineering - Concrete Technology - Discussion

Discussion Forum : Concrete Technology - Section 1 (Q.No. 29)
29.
If 20 kg of coarse aggregate is sieved through 80 mm, 40 mm, 20 mm, 10 mm, 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron and 150 micron standard sieves and the weights retained are 0 kg, 2 kg, 8 kg, 6 kg, 4 kg respectively, the fineness modulus of the aggregate, is
7.30
7.35
7.40
7.45
none of these.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
44 comments Page 4 of 5.

Snehal Nikam said:   1 decade ago
How it is possible?

Hardik said:   1 decade ago
Approximately maximum near by value is taken as A answer.

Nirav Bhatt said:   1 decade ago
Pass Wt Cum Wt. %Cum %cum.

Retained % passing.

0 0 0 100.
2 2 10 90.
8 10 40 50.
6 16 30 20.
4 20 20 0.
--- --- --- ---.
20 48 100 260.

Sieves used are 10.

Hence FM = (10*100-260)/100 = 7.4.

In method suggested by @Kishor, the total is done individually for each sieve where as here it is done by using the nos. sieve.

Both the methods are correct. So the Answer is 7.4.

KISHORE said:   1 decade ago
% RETAINED CUMULATIVE % RETAINED

80 MM 0 0 0
40 2 10 10
20 8 40 50
10 6 30 80
4.75 4 20 100
2.36 0 0 100
1.18 0 0 100
600 0 0 100
300 0 0 100
150 0 0 100

TOTAL 740.

FINENESS MODULUS = 740/100 = 7.4.

Sanu sonkamble said:   9 years ago
Thanks Kishorn & Jagadeesh.

Vinod said:   9 years ago
Fineness modulus of given course aggregate is 740/100 =7.4.

Bapureddy said:   9 years ago
I didn't get it. Please, Can anyone explain it clearly?

Naman said:   9 years ago
I didn't get this, Please explain briefly.

Sanjana said:   9 years ago
Can anyone explain last column?

Sudip said:   9 years ago
Sieve.size wt. retained(kg) %wt.retained(%) cumulative%

80 0 0 0.

40 2 10 10.

20 8 40 50.

10 6 30 80.

7.5 4 20 100.

4.75 0 0 100.

2.36 0 0 100.

1.18 0 0 100.

600 0 0 100.

300 0 0 100.

150 0 0 100.

-----------------

Total = 740.

-----------------

Fineness modulus of given course aggregate is 740/100 = 7.4.
For wt. retained in %, for 40mm sieve size, (2/20)*100% where 20 is the total wt.


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