So here is situation. 4000 psi specified for some piers and here are some break results:
7day 1st cylinder: 3890
7day 2nd cylinder: 3040
14 day : 3430
28 day: 3820
The contractor took a core for another test but the question has come up whether there is some allowance in the required 4000 psi. From what I understand, in this case they have to do two tests (1 cyliner, and 1 core @ 28days) and if one result is below the required f’c but the average is equal or above, results would be acceptable.
If however the results are below 4000 psi, then I don’t see any other way then checking the existing piers to see if they’ll work with the reduced strength. I couldn’t find anything in ACI 318 that would allow an allowance to be below the required f’c.
Is this the correct way to approach the issue? I am not worried about the integrity or the reduced strength, even 3000 psi should work, I just thought this was a great learning opportunity.
7day 1st cylinder: 3890
7day 2nd cylinder: 3040
14 day : 3430
28 day: 3820
The contractor took a core for another test but the question has come up whether there is some allowance in the required 4000 psi. From what I understand, in this case they have to do two tests (1 cyliner, and 1 core @ 28days) and if one result is below the required f’c but the average is equal or above, results would be acceptable.
If however the results are below 4000 psi, then I don’t see any other way then checking the existing piers to see if they’ll work with the reduced strength. I couldn’t find anything in ACI 318 that would allow an allowance to be below the required f’c.
Is this the correct way to approach the issue? I am not worried about the integrity or the reduced strength, even 3000 psi should work, I just thought this was a great learning opportunity.
