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Carpentry Level 2 BC 2023 > G7 - LT #1 Conc. Finishing > Flashcards

G7 - LT #1 Conc. Finishing Flashcards

1
Q

What stages of finishing is an edger used and why?

A

1) After bull floating, pushes large aggregates AWAY from the surface
2) Rounds over

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2
Q

What is the purpose of hand floating and bull floating?

A

Pushes large aggregates down & allows bleed water to escape.

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3
Q

Is a divider tool deep enough for control joints?

A

No

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4
Q

When is the placing of the concrete completed?

A

After floating process

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5
Q

Why should bleed water be allowed to evaporate first?

A

1) Not to dilute the concrete
2) causes dusting and crazing if you do not

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6
Q

How to broom finish?

A

Float, edge, trowel, broom and edge again

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7
Q

When are screeds removed from the concrete?

A

After strike-off

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8
Q

What is the purpose of a screed?

A

Elevated guide for strike off

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9
Q

How is the top of a concrete wall finished?

A

Remove the cleats from formwork and then float

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10
Q

What is the purpose of kneed boards?

A

Distributes weight evenly

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11
Q

What tool is used to transfer flexible patterns?

A

Tamper

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12
Q

5 precautions to consider when finishing a concrete slab with a power trowel?

A

1) Concrete is flat & level
2) Will bear the pressure
3) bleed water is evaporated
4) cover entire surface uniformly
5) allow concrete to harden between passes

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13
Q

How is the movement of a power trowel controlled?

A

1) Increase RPM to engage blade rotation
2) Push down on handles to move right & lift up to move left

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14
Q

What is a burnished surface?

A

Mirror-like finish, made by making many passes with a power trowel at high speeds and a steep angle.

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15
Q

What are two different types of blades used with power trowels?

A

Float & Trowel

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16
Q

What safety precautions must be taken with concrete treatments?

A

Read the SDS Safety Data Sheet

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17
Q

What are the environmental concerns associated with concrete treatments?

A

Streams & groundwater

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18
Q

Describe how sealers and hardeners also act as a curing compound.

A

Coat the surface to stop moisture.

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19
Q

How is exposed aggregate wall surface created?

A

Uniform coat of retardant, painted on the forming material, don’t slide concrete surface of coated form & strip carefully

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20
Q

What is the difference between dampproofing & waterproofing materials?

A

Moisture vs. hydrostatic pressure

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21
Q

How is a suspended concrete slab waterproofed?

A

Membrane roofing

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22
Q

The top of a concrete wall that is left exposed must be finished with:

A

A steel trowel

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23
Q

How can chamfer on concrete be made?

A

Chamfer strip in formwork or an edging tool

24
Q

Should well-proportioned concrete have excessive bleed water?

A

No

25
Q

What is concrete flatwork?

A

A slab that is suspended or placed on grade. Also surfaces of concrete landing and treads in concrete stairs.

26
Q

When does the finishing process of concrete start?

A

After bleeding water evaporates & carpenter can put weight on it with knee boards

27
Q

Can you add water to a concrete mix to ease placement?

A

No

28
Q

Is rebar at the bottom of a form or on ground effective?

A

No

29
Q

What is the purpose of screeding?

A

Levels off the concrete to the elevation set by the screeds?

30
Q

When is floating done

A

After concrete has been placed & screeded to level

31
Q

How are larger areas floated?

A

Bull float for larger areas

32
Q

Can a power trowel be used if bleed water is still remaining?

A

A power trowel should not be used until the bleed water has evaporated

33
Q

How does crazing occur?

A

Floating during bleed water period,changing the w:c ratio, surface cures at a different rate, dusting also occurs

34
Q

A large flat steel trowel is used first, is placed flat or on a steep angle?

A

Flat

35
Q

The second finishing, a smaller trowel is used, is it placed flat or on a steep angle?

A

Steep angle, allowing more pressure

36
Q

On exterior concrete walks and driveways, what sort of finish is needed?

A

A broom trowel, to prevent slips

37
Q

When is a broom trowel done?

A

After a single steel trowel is done

38
Q

When is an edger used?

A

Before each troweling and as the last step of a broom finish

39
Q

When is a fresno used?

A

Used to flatten out the ridges left by the bull float

40
Q

For flexible stamps, what tool is necessary?

A

A tamping tool

41
Q

Power trowel can be used in addition to or as an alternative to

A

The bull float, Fresno & steel trowel

42
Q

With a power trowel, which 2 blades are common?

A

Floats and trowel blades

43
Q

A float blade on a power trowel does what?

A

Final leveling of the concrete surface. Blade typically 10”, kept flat initially. Run at 1/2 to 3/4 speed.

44
Q

What is crossover floating?

A

The second pass on a power trowel, the blades are tilted slightly and the engine is run at 3/4 speed

Allows finisher to reach areas that were hard to access when travelling the first direction and helps level the slab

45
Q

On a power trowel, what does a trowel blade do?

A

Similar to the blade of a hand trowel, typically 8” wide

each pass increases the density of the slab surface, with enough passes the op. can burnish the surface to a mirror-like finish

46
Q

The handles on a power trowel work how?

A

Lifting handing moves to the left, lowering moves to the right

47
Q

What is a curing compound?

A

Membrane curing compound consists of chemicals and waxes that are sprayed, brushed, or rolled on.

Protect from early drying, in hot windy weather.

48
Q

What is a sealer?

A

Sealers are chemicals that the seal of the surface of concrete, prevent formation of dust on a worn concrete surface.

49
Q

What is a chemical hardener?

A

Provide hard-wearing concrete surface and prevent dusting. Also, act as sealers.

50
Q

Metallic or aggregate hardeners?

A

Used in areas where very heavy wear is, dry the top of concrete as it is being finished. made from iron, steel, or hard mineral aggregates

51
Q

Describe exposing aggregates

A

Vertical forms can be treated with chemicals that prevent the cement paste from setting on the surface next to the.

Exposing chemicals are sprayed on slabs to retard the setting of the cement paste

52
Q

What is a bond breaker?

A

These chemicals are used to break the bond between layers of concrete, such as those used to tilt-up construction where multiple layers of concrete are cast one on top of the other.

53
Q

What are bonding agents?

A

Epoxies and adhesives are used to create a good bond between fresh concrete placed over old concrete

54
Q

What is dampproofing?

A

Below grade foundations should be coated on the outside with a dampproofing agent

55
Q

What is waterproofing?

A

Concrete foundations subject to hydrostatic pressure must be waterproofed.

56
Q

How are pigments added?

A

During concrete mixing or may be shaken onto the surface of the concrete when the slab is being finished

Carpentry Level 2 BC 2023 (50 decks)

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