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2 Builders (Exam Review Tools for Trade) > Concrete and Reinforcement (Overview) > Flashcards

Concrete and Reinforcement (Overview) Flashcards

1
Q

There are two ways to insure proper curing of concrete: apply water to make up for water lost due to evaporation, and __________________ .

A

Supply heat to strengthen it (Steaming combines both)

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2
Q

True or False. When pouring concrete, the concrete should be placed near its required point. Excessive handling of the concrete weakens it.

A

True

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3
Q

Pouring concrete on frozen earth is:

a: Acceptable if fast drying concrete is used.
b: Acceptable if air-entrainment concrete is used.
c: Acceptable if the surrounding earth is treated with chloride
d: Never acceptable

A

d: Never acceptable

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4
Q

The diameter of a No. 4 deformed bar is:

a: 1/4”
b: 3/8”
c: 1/2”
d: 3/4”

A

c: 1/2”

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5
Q

Which of the following are true in regard to cold-weather construction?

a: Water for mixing can be heated
b: Insulated blankets can be placed over concrete footings
c: Aggregate can be heated
d: All of the above

A

d: All of the above

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6
Q

When sawing a control joint in a concrete slab, the joint must be a minimum of how deep?

a: 1/5 the thickness
b: 1/4 the thickness
c: 1/2 the thickness
d: 2/3 the thickness

A

b: 1/4 the thickness

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7
Q

The most precise way of positioning rebar for a slab is to use:

a: Stirrups
b: Tables
c: Stools
d: Spacers

A

a: Stirrups

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8
Q

True or False. Chairs are classified according to their degree of rust protection. Class #1 is the maximum protection, class #2 is moderate protection, and class #3 is no protection.

A

True

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9
Q

Proper __________________ prevents most problems in the finished concrete. Methods used to ensure a high quality, finished product, include a sprayed on membrane curing compound, polyethylene sheets, waterproof paper or wet burlap.

a: Curing
b: Seasoning
c: Basting
d: Besting

A

a: Curing

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10
Q

A _________________ is a 12” high cone which determines the amount of water in the mix.

a: Waffle cone
b: Masonry cone
c: concrete cone
d: Slump cone

A

d: Slump cone

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11
Q

In cases of severe cold weather exposure, the air content in a concrete mix should be about:

a: 3% to 5%
b: 5% to 7%
c: 8% to 10%
d: 10% to 12%

A

b: 5% to 7%

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12
Q

If concrete is exposed to de-icers and it is not air entrained, it could:

a: Bleach the surface
b: Darken
c: Scale or spall
d: Buckle

A

c: Scale or spall

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13
Q

When concrete becomes flaky and fragmented on the surface, this is called:

a: Scaling or spalling
b: Spider crackling
c: Buckling
d: Lifting

A

a: Scaling or spalling

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14
Q

The maximum size aggregate is limited to the lesser of:

a: One quarter the thickness of nonreinforced slabs
b: Three-fourths the clear spacing between the bar and the side of the form
c: One-fifth the narrowest distance between sides of the form
d: b and c

A

D: b and c

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15
Q

How much does one cubic foot of concrete weigh?

a: 0.86 lbs.
b: 94 lbs
c: 150 lbs
d: 4050 lbs.

A

c: 150 lbs.

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16
Q

Concrete is considered to be fully cured or set after ______________days.

a: 14 days
b: 21 days
c: 28 days
d: 30 days

A

c: 28 days

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17
Q

True or False. Air entrainment protects concrete from frost damage, but also makes concrete more workable. For that reason, not as much water is necessary for the mix.

A

True

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18
Q

On hot sunny days in the summertime, a contractor may decide to use ____________ to slow down the setting time of concrete.

a: Water
b: Retarders
c: Chloride
d: A tarp

A

b: Retarders

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19
Q

Concrete is made by mixing:

a: Lime, Portland cement, and water
b: Cement, sand, water, gravel
c: Lime, mortar, and water
d: None of the above

A

b: Cement, sand, water, gravel

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20
Q

Adding too much water to a concrete mix will _______________ it.

a: Strengthen
b: Drown
c: Lighten
d: Weaken

A

d: Weaken

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21
Q

_________________ concrete is the process of leveling the freshly poured concrete before it is floated.

a: Screeding
b: Brushing
c: Raking
d: Stomping

A

a: Screeding

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22
Q

True or False. Floating of the freshly screeded concrete is accomplished with a wood or magnesium bullfloat which smoothes out, levels, compacts and brings the small particles to the surface for finishing.

A

True

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23
Q

On large areas, it may be necessary to use a __________________ to finish the surface area.

a: Large finish trowel
b: Bullfloat
c: 2 X 12
d: Power trowel

A

d: Power trowel

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24
Q

On sidewalk surfaces, it is necessary to broom the surface of concrete to provide a:

a: Non-slip surface
b: Clean sidewalk
c: Bubble-free surface
d: More durable surface

A

a: Non-slip surface

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25
Q

It is necessary to maintain the temperature above 50 degrees in order for concrete to properly:

a: Dissipate
b: Strengthen
c: Cure
d: Level off

A

c: Cure

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26
Q

Welded wire mesh should be placed _____below the top surface of the slab.

a: 1 inch
b: 2 inches
c: 4 inches
d: None of the above

A

b: 2 inches

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27
Q

The white salty powder that forms on the finished surface of concrete is called ___________.

a: Sodium
b: Dust
c: Lime
d: Efflorescence

A

d: Efflorescence

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28
Q

A concrete floor may also be called a:

a: Cement on pond
b: Slab on ground
c: Lower elevation
d: Slag

A

b: Slab on ground

29
Q

Concrete slabs on grade have a tendency to curl because:

a: the ground may settle
b: The top cures faster
c: The middle is heavier
d: The sides are lighter

A

b: The top cures faster

30
Q

As concrete is placed in a form it needs to be leveled off. This can be done manually or mechanically with a __________________________.

a: Power trowel
b: Power screed
c: Power stomper
d: Power washer

A

b: Power screed

31
Q

A control joint allows for what?

a: Leveling the foundation
b: A place for a girder to rest
c: Movement
d: None of the above

A

c: Movement

32
Q

What is the purpose of adding retarders to a concrete mixture?

a: To cause the concrete to set faster
b: To increase the amount of water needed to mix concrete
c: To slow down the setting time of concrete
d: To increase shrinkage as the concrete dries

A

c: To slow down the setting time of concrete

33
Q

What is added to make concrete more workable with less water?

a: Fly ash
b: Accelerators
c: Retarders
d: Water reducers

A

d: Water reducers

34
Q

A one car driveway should have a minimum width of?

a: 8’
b: 10’
c: 12’
d: 16’

A

b: 10’

35
Q

A two car wide driveway is usually how wide?

a: 14’
b: 16’
c: 18’
d: None of the above

A

c: 18’

36
Q

Where concrete is cast against and permanently exposed to the earth, reinforcement steel should be __________________ from the earth.

a: 1”
b: 2”
c: 3”
d: 4”

A

c: 3”

37
Q

In most specifications, adding water to a batch of concrete is permitted only one time at the job site as long as the WC ratio is not exceeded. This would be done in order to:

a: Increase the slump to the level specified in the mix design
b: Make cleanup easier
c: Speed up the job
d: The workman’s preference

A

a: Increase the slump to the level specified in the mix design

38
Q

A method to prevent cast concrete from excessive shrinking is to:

a: Increase the cement factor and reduce the size of the aggregate
b: Lower the cement factor and increase the size of the aggregate
c: Use more steel
d: Add calcium chloride

A

b: Lower the cement factor and increase the size of the aggregate

39
Q

Contraction joints, also known as control joints, in a slab are used to:

a: Control random cracking
b: Create dimensional character
c: Water drainage
d: Segregate the slab

A

a: Control random cracking

40
Q

Isolation joints isolate differing parts of a structure to permit independent:

a: Structures
b: Design
c: Movement
d: Placement

A

c: Movement

41
Q

________________________ are a convenient way to limit the size of the placement of concrete to a manageable volume and are a stopping place for a day’s work.

a: Construction joints
b: Contraction joints
c: Isolation joints
d: Control joints

A

a: Construction joints

42
Q

For a slab placed below grade, it is necessary to provide at least 4” of crushed gravel or stone. This should be compacted. It will prevent moisture from collecting under the slab. This 4” area is known as ________________________.

a: Aggregate fill
b: Extra aggregate
c: Dry-base
d: Base

A

d: Base

43
Q

The timing for the removal of forms is important. The concrete has to achieve a strength great enough to support its own weight and the weight of any construction loads placed upon it. General guidelines for wall and column form removal is _________________________ after placement.

a: At least 12 hours
b: At least 24 hours
c: At least 36 hours
d: At least 48 hours

A

a: At least 12 hours

44
Q

Concrete that has a lot of Portland cement in the mix may be referred to as:

a: High mix
b: Max mix
c: Rich concrete
d: Fat mix

A

c: Rich concrete

45
Q

What is the reason for using fiber reinforcement in concrete?

a: Improves ductility and reduces surface cracks
b: It’s a cheap filler
c: It increases temperate strength
d: Increases compression strength

A

a: Improves ductility and reduces surface cracks

46
Q

What is used to prevent concrete from sticking to wood forms?

a: Greese
b: Form release agent (oil)
c: Concrete will not stick to wood
d: None of the above

A

b: Form release agent (oil)

47
Q

The most commonly used additive to help concrete set rapidly and more cohesively is:

a: Calcium chloride
b: Fly ash
c: Hydrochloric acid
d: Paint catalyst

A

a: Calcium chloride

48
Q

With the exception of special conditions, maximum delivery time between the water being mixed with the Portland cement in batching and the time of completion of discharge from a transit-mix truck is __________________________.

a: 30 minutes
b: 60 minutes
c: 90 minutes
d: 120 minutes

A

c: 90 minutes

49
Q

What is the sole purpose for welded wire fabric in a floor slab?

a: Increase the load carrying capacity
b: Prevent slab from cracking
c: Prevent cracks from opening
d: All of the above

A

c: Prevent cracks from opening

50
Q

True or False. The reason for tying reinforcing bars with tie wire is to keep the rebar in place while pouring. It does not add any additional strength to the concrete.

A

True

51
Q

Concrete slabs poured above grade are often supported by ribbed or corrugated steel decking. These forms are called __________ .

a: Slip forms
b: Jump forms
c: Stay-in-place forms
d: Gang forms

A

c: Stay-in-place forms

52
Q

True or False. Rebar is placed in concrete mainly to improve its compression strength.

A

False, its mainly to improve its tensile strength

53
Q

What is the usual size of tie wire for rebar placement?

a: #8 gauge soft annealed
b: #12 gauge soft annealed
c: #14 gauge soft annealed
d: #16 gauge soft annealed

A

d: #16 gauge soft annealed

54
Q

Reinforcing steel placed in concrete to increase is _________strength.

a: Compression
b: Tensile
c: Soil compaction
d: None of the above

A

b: Tensile

55
Q

Ready mix concrete is purchased by the cubic yard, which is how many cubic feet?

a: 144
b: 27
c: 12
d: 48

A

b: 27

56
Q

The thermal process known as hydration refers to:

a: Air entrainment of concrete
b: Freeze and thaw conditions of concrete
c: The curing process
d: None of the above

A

c: The curing process

57
Q

A slump cone is a metal cone used for:

a: Determining water mix in concrete
b: Pouring cement into small places
C: Measuring amount of cement used
d: None of the above

A

a: Determining water mix in concrete

58
Q

The minimum compressive strength of concrete for slabs in moderate weather exposure is_______.

a: 2000 lb
b: 2500 lb
c: 3000 lb
d: None of the above

A

c: 3000 lb

59
Q

Reinforced concrete is accomplished by adding:

a: Reinforcing rod
b: Welded wire
c: Stronger cement
d: either a or b

A

d: either a or b

60
Q

The term “fine aggregate” refers to well-graded gravel up to:

a: 1/4 inch
b: 1/8 inch
c: 3/8 inch
d: 5/8 inch

A

a: 1/4 inch

61
Q

In comparison to regular concrete, air entrained concrete:

a: Has more workability
b: Is more watertight
c: Is more durable in freeze/thaw conditions
d: Both a and c

A

d: Both a and c

62
Q

If fill needs to be added for a slab-on-grade, it should be compacted in successive layers of not more than_____inches thick at a time.

a: 24
b: 18
c: 6
d: All of the above

A

c: 6

63
Q

A number 3 rebar is what diameter?

a: 1/8 inch
b: 1/4 inch
c: 3/8 inch
d: 1/2 inch

A

c: 3/8 inch

64
Q

When water is added to Portland cement it causes the mass to set. This reaction is called:

a: Admixtures
b: Hydration
c: Entrainment
d: Mixing

A

b: Hydration

65
Q

For garage floor slabs where a steel trowel finish is used, the total air content can be reduced to ____percent provided the strength of the concrete is increased to 4000 psi.

a: 3
b: 5
c: 7
d: All of the above

A

a: 3

66
Q

True or False. Concrete cures best in cool, damp environments.

A

True

67
Q

Besides ensuring the proper strength of concrete, proper curing of concrete also aids in:

a: Durability
b: Surface soundness
c: Reducing cracking
d: All of the above

A

d: All of the above

68
Q

What is the minimum thickness of concrete footings for fireplaces?

a: 10”
b: 11”
c: 12”
d: 14”

A

c: 12”

69
Q

What is the minimum thickness of concrete used for floors?

a: 3”
b: 3 1/2”
c: 4”
d: 4 1/2”

A

b: 3 1/2”

2 Builders (Exam Review Tools for Trade) (16 decks)

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