ASTM C 172, Sampling Flashcards
The elapsed time between obtaining the first and final portions of a composite sample shall not exceed _____minutes.
A. 2
B. 5
C. 10
D. 15
15
When it is necessary to wet sieve a concrete sample, wet sieving should be performed before the individual samples are combined into a composite sample.
(T or F)
True
Tests for slump, temperature, and air content shall all be started within _____ minute(s) after obtaining the final portion of the composite sample.
A. 1
B. 2
C. 5
D. 15
5
Start molding strength test specimens within _____ minute(s) after fabricating the composite sample.
A. 1
B. 2
C. 5
D. 15
15
The sample of concrete should be
A. allowed to sit, undisturbed, in the container for 5 minutes before conducting any tests.
B. protected from the sun, wind, rapid evaporation, and contamination.
C. remixed with material re‐deposited in the container following the slump test.
D. remixed with additional water if the sample dries out during use.
protected from the sun, wind, rapid evaporation, and contamination.
When test specimens are to be molded, the minimum sample size is _____ .
A. 1 ft^3
B. 2 ft^3
C. 0.5 ft^3
D. 5 ft^3
1 ft^3
The primary objective when sampling concrete is to
A. obtain a representative sample of concrete.
B. obtain 1 ft^3 of concrete.
C. minimize the contamination of the sample.
D. provide experience with we sieving a sample of concrete.
obtain a representative sample of concrete.
When sampling from a revolving drum truck mixer, collect
A. one portion from anywhere in the batch.
B. all portions before water or admixtures have been added to the batch.
C. two or more portions at regular intervals from the middle of the batch.
D. all portions before placing any concrete in the forms.
two or more portions at regular intervals from the middle of the batch.
Wet sieving is performed
A. on all composite samples.
B. only when the Nominal Maximum Size (NMS) of the coarse aggregates is larger than 3 inches.
C. after the sampled portions are remixed onto a composite sample.
D. when the aggregate is larger than appropriate for a test.
when the aggregate is larger than appropriate for a test.
When sampling from a paving mixer, it is permissible to place three shallow containers on the subgrade in
order to obtain the needed portions of concrete.
(T or F)
False
Regulate the rate at which concrete is discharged from a revolving drum truck mixer by
A. adjusting the size of the gate opening.
B. changing the angle of the discharge chute.
C. placing a hand held dam in the chute.
D. adjusting the rate of revolution of the drum.
adjusting the rate of revolution of the drum.
After wet sieving a portion of a concrete sample, any aggregate retained on the sieve
A. shall be remixed with the remaining portion of the original sample.
B. shall be discarded.
C. should have any mortar on the particles wiped off and added to the sieved material.
D. is to be recombined with the sieved material before fabricating strength specimens.
Shall be discarded
Samples from a revolving drum truck mixer
A. should be of approximately equal volumes.
B. can be placed into the formwork after all tests have been completed.
C. should not be taken until all water and any admixtures have been added to the mixer.
D. should be take for each individual test performed on the fresh concrete.
should not be taken until all water and any admixtures have been added to the mixer.
When sampling from a paving mixer, obtain _____ portions from the discharge pile.
A. at least 5
B. no more than 5
C. 3 to 5
D. 2 or more
at least 5
Sample concrete from a revolving drum truck mixer by
A. repeatedly passing a receptacle through the entire discharge stream.
B. completely diverting the discharge into a sample container.
C. neither A nor B.
D. either A or B
either A or B
A: repeatedly passing a receptacle through the entire discharge stream.
B: completely diverting the discharge into a sample container
