11-52.
When seawater is used to mix
concrete, what compensation must
be made to maintain compressive
strength?
1.
Increase the water-cement
ratio
2.
Decrease the water-cement
ratio
3.
Use Type III cement
4.
Use waterproofed cement
11-53.
Aggregate should have what shape
to increase workability?
1.
Rounded
2.
Subrounded
3.
Subangular
4.
Angular
11-54.
What is the maximum size a coarse
aggregate should be in a heavily
reinforced slab, 7 inches thick?
1.
1
inch
2.
2
inches
3.
1 1/2 inches
4.
2 1/2 inches
11-55.
To remove silts, clays, and
organic material in the aggregate
to be used in a concrete mix,
which of the following actions
should you take?
1.
Drying
2.
Burning
3.
Washing
4.
Heating
11-56.
What is the recommended amount for
the sampling of a stockpile that
is used for the tests?
1.
The amount needed
2.
Twice the amount needed
3.
Three times the amount needed
4.
Four times the amount needed
11-57.
What is the name of the value that
gives a relative measure of the
proportions of fine and coarse
particles in an aggregate?
1.
Fineness module
2.
Gradation of the sample
3.
Aggregate grading
4.
Gradation limits
11-58.
When you test the aggregate for
soundness, what test, other than
the freeze-thaw test, may be
performed?
1.
Fines test
2.
Color test
3.
Salt test
4.
Wash test
11-59.
What is the recommended amount of
fines in concrete to achieve good
workability?
1.
0.0 to 1.0 percent
2.
1.1 to 2.9 percent
3.
3.0 to 5.0 percent
4.
Above 5 percent
11-60.
When the percentage of fines in a
sample is 5 percent and the dry
weight is 1,995 grams, what is the
original dry weight of the sample?
1.
1,895 grams
2.
2,005 grams
3.
2,095 grams
4.
2,100 grams
11-61.
When you test for undesirable
lightweight material, what is
the size of sieve used for coarse
aggregate?
1.
1/4 inch
2. No. 4
3.
No. 10
4.
No. 50
11-62.
When do you perform the test
for clay lumps?
1.
Before sieve analysis
2.
After sieve analysis
3.
After washing
4.
Both 2 and 3 above
11-63.
You have performed the color test
and determined that organic
material is present in the sand.
Which of the following options
should be taken?
1.
Find a replacement sand
2.
Wash the existing sand
3.
Use a lower water-cement ratio
4.
Each of the above
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