Civil Engineering - Concrete Technology - Discussion

34. 

The preliminary test is repeated if the difference of compressive strength of three test specimens, exceeds

[A]. 5 kg/cm2
[B]. 8 kg/cm2
[C]. 10 kg/cm2
[D]. 12 kg/cm2
[E]. 15 kg/cm2

Answer: Option E

Explanation:

No answer description available for this question.

Amitgoel said: (Jul 30, 2014)  
Please explain your thought. ! As per IS-456, allowable % age is 15% between three adjacent cubes.

Madhu C N said: (Sep 8, 2014)  
Usually test is repeated if 5% of specimens failed to satisfy the results right.

Pankaj Mehra said: (Nov 19, 2014)  
As per IS 516 Average of three values shall be taken as the representative of the batch provided the Individual variation is not more than ± 15 percent of the average.

Otherwise repeat tests shall be made.

Abhi said: (Mar 19, 2015)  
5% difference is not considered during test. It is the difference of 15%.

Jinx said: (Aug 14, 2015)  
I didn't get the specimens details it is a cement mortar or concrete cubes.

Shivam said: (Aug 18, 2015)  
AS PER IS-456 "The test results of the sample shall be the average of the strength of three specimens".

The individual variation should not be more than +15 percent of the average. If more, the test results of the sample are invalid.

Galelio said: (Oct 6, 2015)  
Question is wrong "Allowable difference can be known if values of compressive strength is know", is 15% of what?

Option should be in %, how you are going to know the value 15kg/cm2. It should be 15%.

Raja said: (Aug 8, 2016)  
I'm agreeing with you complete Galileo.

Uday said: (Oct 28, 2017)  
Strength difference of 15kg/cm2 for 3successive cubes or 5% cubes fails, then test repeated.

Bharaneedharan said: (Feb 13, 2018)  
15kg/mm2 means 1.5N/mm2.

Am I right?

Ashish said: (May 18, 2018)  
The individual variation of test reading should not exceed 15% of the average.

Sagar said: (Aug 30, 2018)  
What action shall be taken if the sample result is invalid based on individual variation is more than 15% despite having the individual test result is 35.17 mpa for M30 grade concrete.

Shall one go for in situ tests?

Please explain me.

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