ASTM C 173, Air Content – Volumetric Flashcards
It is permissible to use ASTM C 173 to determine the air content of fresh concrete made with
A. dense aggregate only.
B. lightweight aggregates only.
C. any type of aggregate.
D. highly porous aggregates
any type of aggregate
ASTM C 173 measures the total volume of air present in
A. both paste (mortar) fraction and aggregates.
B. the mortar fraction only.
C. porous, lightweight aggregate particles.
D. the aggregate fraction only.
the mortar fraction only
The purpose for adding isopropyl alcohol to the volumetric meter is to
A. fill the meter more quickly.
B. reduce costs, as alcohol is cheaper than tap water.
C. help the paste separate from the bowl when dumped out at the end of the test.
D. help dissolve the foam that can be created during the test
help dissolve the foam that can be created during the test.
When the coarse aggregate of a concrete mixture can be retained on a 1‐1/2 inch sieve, wet sieve a sufficient amount of material for the air content test (ASTM C 173) over a ______ inch sieve.
A. 1/2
B. 3/4
C. 1
D. 1‐1/2
1
The bowl of the volumetric meter is filled in _____ layer(s) of approximately equal volume.
A. 1
B. 2
C. 3
D. 4
2
Excess concrete above the rim of the bowl is struck off using
A. a strike‐off bar.
B. a strike‐off plate.
C. the tamping rod.
D. either a strike‐off bar or strike‐off plate.
a strike-off bar
Prior to adding any isopropyl alcohol to the meter, it is necessary to add at least _____ of water to the meter.
A. 1 cup
B. 1 pint
C. 1 quart
D. 1 gallon
1 pint
During the inversion and shaking processes, the minimum total of time that the meter should be inverted is
A. 5 seconds.
B. 20 seconds.
C. 45 seconds.
D. 1 minute.
45 seconds
During the inversion and shaking processes, the maximum total of time that the meter should be inverted is
A. 5 seconds.
B. 30 seconds.
C. 45 seconds.
D. 1 minute.
5 seconds
The rolling process should be continued for approximately
A. 5 seconds.
B. 30 seconds.
C. 45 seconds.
D. 1 minute.
1 minute
The liquid level in the neck of the meter is considered stable when
A. two readings are within 0.25% of each other.
B. a reading can be taken to the nearest 0.25%.
C. there is less than 2 percent increments of foam in the neck.
D. the liquid level does not change more than 0.25% in 2 minutes.
the liquid level does not change more than 0.25% in 2 minutes
Whenever a reading of the liquid level is taken, the reading is rounded to the nearest
A. 0.25%
B. 0.50%
C. 1%
D. 0.1%
0.25%
A test must be discarded if the amount of foam present in the neck is equivalent to _____percent air content divisions, or more, over the liquid level
A. 0.25
B. 0.50
C. 1
D. 2
2
Confirmation of the initial meter reading is obtained when the difference between the initial and final meter readings are within ____ of each other
A. 1%
B. 0.10%
C. 0.50%
D. 0.25%
0.25%
When taking a reading of the liquid level, read to the
A. top of the meniscus.
B. top of the foam.
C. bottom of the meniscus.
D. bottom of the foam.
bottom of the meniscus
If undisturbed, tightly packed concrete is found adhering to the bowl of the volumetric meter when emptied
A. apply the aggregate correction factor to the final meter reading.
B. apply the alcohol correction factor to the final meter reading.
C. use extra care in cleaning the equipment.
D. discard the test, as the results are invalid.
discard the test, as the results are invalid
The final meter reading from the neck is found to be 5.25%. Three pints of alcohol were added to the water giving a correction factor of 0.25 (Table 1). There was no need to add calibrated cups of water to the meter. The final air content from this test is
A. 5.25 – 0.25 = 5.0%
B. 5.25 + 0.25 = 5.5%
C. 5.25 x 0.25 = 1.31 rounded to 1.25%
D. 5.25%
5.25-0.25 = 5.0%
If the liquid level falls below the bottom of the site glass,
A. discard the test as an air content greater than 9% violates the specifications.
B. discard the test and run a new test adding more alcohol.
C. add a sufficient number of calibrated cups of water to bring the liquid level into the visible range.
D. add a sufficient number of calibrated cups of alcohol to bring the liquid level into the visible range.
add a sufficient number of calibrated cups of water to bring the liquid level into the visible range.
If the liquid level fails to stabilize within 6 minutes
A. repeat the inversion and shaking process.
B. discard the test and run a new test adding more alcohol.
C. repeat the rolling process.
D. the volumetric air test is then not applicable to the particular concrete mixture.
discard the test and run a new test adding more alcohol.
If there is excessive foam above the level of liquid, calibrated cups of isopropyl alcohol shall be added to the meter to disperse the foam.
(T or F)
False
Concrete previously used to perform another test, such as the slump test, can be used to determine air content.
(T or F)
False
To free concrete from the measuring bowl,
A. shake the meter up and down making sure aggregate does not lodge in the neck.
B. invert the meter, shake the bowl up and down, then return to the upright position.
C. invert the meter 45 degrees, shake the bowl forward and back, then return to the upright position.
D. invert the meter, shake the bowl horizontally, then return to the upright position.
invert the meter, shake the bowl horizontally, then return to the upright position.
