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