If footing Concrete done with grade of concrete m30 cube test fail at 28 days., what to do next proceed

If your 28days cube fails then you can go for additional test like rebound hammer/core cutting/ultra sonic test.
But still it fails on those tests the work may rejected and additional strengthening of the structure shall be considered.
 
Engage the structural engineer of record in the issue. Any supplemental test results that you've acquired (as Er. P K S above mentions) should be located & charted on drawings so that the SE can analyze the specific locations & conditions. Your supplemental testing program should seek to isolate the low strength condition, if possible. You may have areas where the supplemental tests could show acceptable results whereby you might be able to narrow down the location(s) of the defective conditions.
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Dnyan Deshmukh

Staff member
There are lot of root causes involve in failure or unsatisfactory cube test results.
It is not easy to detect the problem either with casting, curing, testing, production, materials etc.

If you are sure about, your concrete is failed, then whatever you are doing further is just in the interest of hiding the blunders which could popup in the future.

If that is not the case, you are on your journey to find the actual root cause to fix the issue.

If I get a free time, will definitely write a book on this subject as this is a very vast and involves multiple aspects and its just like creating a movie which has all genres packed in it to highest level. there are scene which are full of comedy, you find some crime scene, suspense, thrill.
In short, it takes lot of examination to conclude the problem and taking decision.

We should always cast higher number of cube sets or atleast cube sets as per IS code frequency this gives us ability to test the concrete in further ages to check the strength gain curve and also for understanding problem in particular lot of concrete or cube casting activity.

If you had extra sets of concrete cubes, you saved a lot for your company because it cost less than what you are going to spend and time is always money which you do not allow to loose due to extra sets.
 
There are lot of root causes involve in failure or unsatisfactory cube test results.
It is not easy to detect the problem either with casting, curing, testing, production, materials etc.

If you are sure about, your concrete is failed, then whatever you are doing further is just in the interest of hiding the blunders which could popup in the future.

If that is not the case, you are on your journey to find the actual root cause to fix the issue.

If I get a free time, will definitely write a book on this subject as this is a very vast and involves multiple aspects and its just like creating a movie which has all genres packed in it to highest level. there are scene which are full of comedy, you find some crime scene, suspense, thrill.
In short, it takes lot of examination to conclude the problem and taking decision.

We should always cast higher number of cube sets or atleast cube sets as per IS code frequency this gives us ability to test the concrete in further ages to check the strength gain curve and also for understanding problem in particular lot of concrete or cube casting activity.

If you had extra sets of concrete cubes, you saved a lot for your company because it cost less than what you are going to spend and time is always money which you do not allow to loose due to extra sets.

In a nutshell civil engineering needs to evolve to address this kind of scenario