問題一覧
1
What concrete has the greatest compressive strength:
M
2
How much dirt is removed from a trench 120 feet long, 2 1/2 feet wide and 5 feet deep, excluding the swell factor for the soil:
55.56 cubicyards
3
Dirt from excavations must be set back how far from the edge of the trench:
2’
4
Rank types of concrete by strength going from highest to lowest:
M.S.N.O
5
Placing concrete in cold weather causes what:
slow curing
6
How much water is allowed to accumulate in a working open trench:
0”
7
What type of Portland cement produces high early compressive strength:
Type IlI
8
What is the most common Portand cement added to concrete:
Type l
9
What is the minimum number of mixing revolutions for concrete under ASTM 94:
75-100
10
What concrete would be used in areas with high phosphate content:
Type V
11
Rebar adds what strength to concrete structures:
tension
12
Form lateral pressures increase by what percentage if adding retarder to Type I, Il, or Ill concrete mixes:
20%
13
What is the diagonal for an excavation measuring 28 × 45:
53’
14
What type of Portland concrete produces high early compressive strength:
type III
15
If working in a trench 5' or more in depth, what is the best way to prevent trench side wall collapse accidents on employees working in the trench:
shoring box
16
For an excavation, what is used as the beginning reference point:
benchmark
17
Plastic shrinkage cracks that occur in concrete during hot weather placement is usually due to what:
rapid loss of surface water
18
What is the minimum spacing for a placed rebar in a reinforced wall:
3 times the width of the wall or 18"
19
Air entertainment improves freeze and thaw resistance and what else:
workability
20
Scaffold planks must overextend their upright supports by how many inches:
12”
21
Adding additional Water to an already workable mix of concrete causes what:
decrease in strength
22
What is the maximum safe load for a form system using snap ties:
3350 lb
23
What causes rebar to bond to concrete better:
rust
24
What is the maximum recommended slump for concrete used in footings:
6
25
The ability of concrete to resist abrasion is closely linked to what other concrete trait:
porosity
26
If digging a trench 5 feet wide, 60 feet long in ground that has a constant slope from O to 8 feet, how many cubic yards of soil will be removed:
between 40 and 45
27
What is added to mix to slow curing during hot weather:
retarders
28
If the rod reading is 165 and the finished rod reading is supposed to be 163 and the transit height is 5.7 feet, what will the reference stake read:
fill 2.00
29
What type of exterior grade plywood is best used for large concrete forms:
HDO
30
If digging a trench that has c continuous slope from O' to 8' that will be 5' wide and 60' long, not considering swell, how many cubic yards of dirt will be excavated:
43-46
31
What is the minimum thickness for a lightweight concrete deck:
2”