( 2 ) Practice C172/C172M-14a Sampling Freshly Mixed Concrete
The minimum size sample for marking strength test specimens is ______.
28 L / 1 Ft³
Start molding specimens for strength test within _______ after fabricating the composite sample.
15 min.
The elapsed time between obtaining the first and final portions of a composite sample shall not exceed _____.
15 min.
Start tests for slump , temperature , and air content within _____ after obtaining the final portion the composite sample.
5 min.
Sampling by this covers procedure for obtaining representative samples , on which tests are to be performed to determine ______ with quality requirements of the specifications under which the concrete is furnished.
Compliance
Concrete samples from a truck mixer must be obtained before any water or admixtures are added to the mixer at the job site. True or False?
False
When sampling from a paving mixer , obtain samples from at lease _____ different portions of the pile and combine them into one composite sample for test purposes.
Five
The composite sample from a truck mixer must be obtained from the _______ portion of the batch.
Middle
The concrete sample must be protected from contamination and ________.
Rapid eveporation
This practice covers sampling from five types of equipment , which are ______ , _______ , _______ ,_______ and _______.
Stationary mixers , paving mixers , revolving drum mixers , continuous mixers , open top mixers
Portions of a composite sample shall be thoroughly remixed before beginning tests on the sample. True or False?
True
When sampling from a revolving drum truck mixer , sample the concrete by collecting ______ or more portions take at regularly spaced intervals during discharge of the middle portion of the batch.
Two
When sampling from a stationary mixer , the batch must be sampled at _____ or more regularly spaced intervals during discharge of the middle portion of the batch.
Two
When the concrete contains aggregate larger than that permitted for a particular test methods , the sample of concrete must be ________ before making the test.
Wet sieved
