11-64.
When you are determining bulk
specific gravity, the aggregate
should be in what condition?
1.
Oven-dried
2.
Air-dried
3.
Super-saturated
4.
Saturated, surface-dried
11-65.
Absorption represents what
moisture content of the aggregate?
1.
The surface moisture
2.
The aggregate at SSD
3.
The aggregate super-saturated
4.
The quantity of water required
for the mix
11-66.
What is the recommended length of
time to soak your sample for the
specific gravity test?
1.
6 hours
2.
12 hours
3.
18 hours
4.
24 hours
11-67.
What procedure assists you in
determining when fine aggregate
has reached SSD?
1.
The wet shaking test
2.
The water-absorption cone
and tamper method
3.
The pycnometer
4.
The Atterberg limits test
11-68.
The oven-dried fines sample
weighed 485 grams. What was
the percentage of absorption?
1.
1.5%
2.
2.0%
3.
2.5%
4.
3.0%
Learning Objective: Identify
admixtures used for concrete and
the effects they have on concrete
characteristics.
11-69.
What results are obtained by
adding accelerators to concrete?
1.
Higher rate of heat production
2.
Slows the hydration process
3.
High-early-strength concrete
with a lower strength
4.
Full hydration does not occur
11-70.
The workability of concrete is
governed by the amount of
aggregate in the mix. When the
aggregate cannot be reduced, what
admixture should you use?
1.
Calcium chloride
2.
Fly ash
3.
Pozzolan
4.
Each of the above
11-71.
Dense concrete is required in
what type of concrete work?
1.
Prestressed structures
2.
Overhead pours
3.
Load-bearing walls
4.
Runways
11-72.
The critical period in the curing
process of concrete occurs at what
time frame?
1.
From the day of placement
through the 10th day
2.
From the day after placement
through the 10th day
3.
From the day of placement
through the 14th day
4.
From the day of placement
through the 28th day
11-73.
What is the ideal temperature
ranges for concrete work?
1.
Below 35°
2.
Between 35° and 50°
3.
Between 55° and 70°
4.
Between 70° and 90°
80
