if Variation is more than 15% then cube sample was failed?

[anuj@89]

if we casted only one sample of concrete mix for testing of compressive strength, but indivisual cube results variation is more 15%.

 

[Sharanu.palled]

In case the cubes are failed that time consult to the structural design engineer .

 

[Bagi.RaviTeja]

If the value is repeating and if you are getting deviation in the 15% Cement content and W/c ratio will be the major factor concern. Any one should check the design mix and adjust site utilities. Control should be taken at site
-15% Cement Content should increase
+15% Cement Content should decrease
As QC point of view

 

[balunbs]

If the individual cube specimen result variation is more than 15% of the sample's average, then that sample's result is to be discarded.

 

[anuj@89]

If the individual cube specimen result variation is more than 15% of the sample's average, then that sample's result is to be discarded.

ok, but i have only one sample, if we discarded this sample then what should we do to confirm actual strength without going any additional test. like NDT or Core cutting Procedure.is there any other way to confirm.

 

[Dnyan Deshmukh]

There should not be a variation of more than 15% in individual cube from the average result of that set.

If you cast the cube as explain in below article, you can easily summarize it as improper cube casting practice which need to be corrected to ensure no false detection in concrete Quality Control.

How to do concrete sampling and cube casting

How to do concrete sampling and cube casting If sampling and cube casting goes wrong, end result of it goes wrong and can create a panic. Concrete cube casting is most important activity as we judge the concrete in place by testing the cubes casted for it. Sample concrete can be taken from...

civil4m.com

For acceptance criteria and failures in concrete, you can refer below article. this will definitely help you in understanding concrete in more broader way.

Concrete Cube Failure and Acceptance Criteria

Concrete Cube Failure and Acceptance Criteria More panic situation in any project comes after failure in cube strength and most of the Engineers or not aware about acceptance criteria of it. I asked many about what is acceptance criteria, most of the people mixed the things and not able to tell...

civil4m.com

Hope it will help you in further concreting activities.