Strength tests for small volumes of concrete

[sdefranco]

Hi everyone, I am new to the forum and have question that hopefully you can help me with...

We are building a reinforced concrete foundation for a small communication tower which requires about 4.5 CY of ready mix.

I note that ACI 318-05 5.6.2.3 states

"When total quantity of a given class of concrete is less than 50 yd3, strength tests are not required when evidence of satisfactory strength is submitted to and approved by the building official."

Does anyone have any advice on what would be considered "evidence of satisfactory strength"?

Thanks!

 

[concretemasonry]

I would imagine that any history of normal mix designs and the producers cylinder breaks for controlled projects would be adequate.

If you are really concerned and it is just compressive strength, specifying a higher strength (only 500 -1000 psi higher) could be justified since it is only 4.5 yards and you can still inspect the placement if you are concerned.

Dick

 

[msucog]

i'd just hire a firm to make the sets and be done with it...it can only help to reduce the overall liability (assuming the tests pass). if no special inspections are required and money is real tight, make the cylinders yourself if you're qualified and have the specimens sent to a firm to be broken.

 

[sdefranco]

Dick, msucog - thanks for your quick responses. Much appreciated!