Civil Engineering - Concrete Technology - Discussion


The maximum amount of dust which may be permitted in aggregates is

[A]. 5% of the total aggregates for low workability with a coarse grading
[B]. 10% of the total aggregates for low workability with a fine grading
[C]. 20% of the total aggregates for a mix having high workability with fine grading
[D]. all the above.

Answer: Option D


No answer description available for this question.

Sadulla Ahmed said: (Jan 24, 2014)  
Option B & C saying that work-ability increases with the increase of dust. I have confusion in these two.

K.P.Singh said: (May 13, 2014)  
20% Dust mix & Proper gain strength for concrete.

Er. Soumya Choudhury said: (Mar 21, 2015)  
Yeah exactly option B and C are countering each other. Any body please clarify.

Parveen Kaushik said: (May 5, 2015)  
Some confusion this concept no 3. Its not correct here 20% of dust all in aggregate not fine aggregate.

Sapan Rijal said: (Dec 29, 2015)  
Deleterious material is permitted only upto 5%. Isn't the dust deleterious one?

Muzaffar said: (Apr 12, 2016)  
In option B and C fine grading is there, so the dust is also a fine material. I think that may be the reason.

Mahi said: (Jul 17, 2017)  
Please anybody clarify this.

Mahesh Ramhari Bajabale said: (Jul 21, 2017)  
Silt content more than 10% in the sand is not allowed. According to IS code.

Ankit said: (Feb 8, 2018)  
Please anybody clarify the answer.

Aadarsh Devkate said: (May 31, 2018)  
No, provision is maximum 5% for all kinds.

Irshad Ahmad said: (Feb 22, 2020)  
By replacing sand with dust strength increases. We have performed this test in the lab. We replaced the sand with crusher dust and as we were increasing the percentage of dust the corresponding strength also increased.

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