ASTM Cards that Jason gave us ASTM C172/C172M
Start molding specimens for strength tests within ______ min after fabricating the composite sample.
15
The elapsed time between obtaining the first and final portions of the composite sample shall not exceed ____ min.
15
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.
2
According to Practice C172/C172M, the minimum size of the sample to be used for strength test is _________ L or 1 ft3.
28
The minimum size sample for making strength test specimens is ________.
28 L (1ft^3)
The tests for slump and air content, or both, must be started within _____ min after obtaining the final portion of the composite sample.
5
When sampling from a paving mixer, obtain samples from at least ________ different portions of the pile and combine them into one composite sample for test purposes.
5
When sampling from a paving mixer, Practice C172/C172M permits the composite sample to be obtained how?
By obtaining samples from at least five different portions of the pile and combining them into one composite sample
When sampling from a stationary mixer, except for a paving mixer, the technician can ensure a representative sample by __________.
Collecting 2 or more samples at regularly spaced intervals and combining them into one composite sample
T or F 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
Some test procedures require that concrete be sieved prior to testing. After removing the larger aggregate particles, the batch is then ________.
Remixed with a shovel
T or F Portions of a composite sample shall be thoroughly remixed before beginning tests on the sample.
True
Sampling by this practice covers procedures for obtaining representative samples, on which tests are to be performed to determine ________ with quality requirements of the specifications under which the concrete is finished.
compliance
The elapsed time between obtaining the first and final portions of the composite sample shall not exceed ____ min.
not exceed 15 min
The concrete sample must be protected from contamination and ________.
rapid evaporation (wind, sun)
This practice covers sampling from five types of equipment, which are ________, ________, ________, ________, and ________.
stationary mixers paving mixers revolving drum truck mixers Continuous mixers open top truck mixers, agitators, nonagitating equipment or other types of open-top containers
To obtain a representative sample from a revolving drum truck mixer, regulate the rate of discharge by________.
the rate of revolution of the drum and not by the size of the gate opening
To obtain a representative sample from a revolving drum truck mixer, regulate the rate of discharge by________.:
the rate of revolution of the drum not by the size of the gate opening
