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CMEC ACI WORKBOOK > ASTM C 138 - DENSITY (UNIT WEIGHT) OF CONCRETE > Flashcards

ASTM C 138 - DENSITY (UNIT WEIGHT) OF CONCRETE Flashcards

1
Q

Volume of Concrete

What is the DEFINITION of YIELD

A

Volume of concrete produced from known weights of component materials.

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2
Q

__ lbs

What must the scale for density measurments be accurate up to?

A

Accurate to 0.1 lbs

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3
Q

__ lbs/ft^3

What is a scales required MAXIMUM measuring capablities for densities of concrete?

A

160 lbs/ft3

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4
Q

5/8 inch +- __ inch

What is the DIAMETER of the tamping rod for concrete density?

A

5/8 inch

+- 1/16 inch diameter

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5
Q

How much LONGER must the tamping rod be than the depth of the mold?

A

4 inches longer

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6
Q

What is the TYPICAL AND MAXIMUM LENGTH of the tamping rod used for densities?

A

24 inches

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7
Q

3/4 inch - __ inch

What must the outside diameter of the vibration rod be between?

A

3/4 inch - 1 1/2 inch

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8
Q

9___ vibrations/minute

What is the MINIMUM vibrating frequency for an internal vibrator? (150 Hz)

A

9,000 vibrations/minute

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9
Q

How much longer must the vibrator be vs. the depth of the density container?

A

3 inches

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10
Q

Every __ years

How often must a vibrator be checked and verified?

A

Every 2 years

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11
Q

What must a vibrator be verified by?

A

Tachometer

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12
Q

If the Nominal Aggregate Size of the sample is 1 inch – What must the MINIMUM bucket volume be?

A

0.2 ft3

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13
Q

If the Nominal Aggregate Size of the sample is 1 1/2 inch – What must the MINIMUM bucket volume be?

A

0.4 ft3

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14
Q

If the Nominal Aggregate Size of the sample is 2 inch – What must the MINIMUM bucket volume be?

A

0.5 ft3

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15
Q

If the Nominal Aggregate Size of the sample is 3 inches – What must the MINIMUM bucket volume be?

A

1.0 ft3

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16
Q

If the Nominal Aggregate Size of the sample is 4 1/2 inch – What must the MINIMUM bucket volume be?

A

2.5 ft3

17
Q

If the Nominal Aggregate Size of the sample is 6 inch – What must the MINIMUM bucket volume be?

A

3.5 ft3

18
Q

M__, P__, G__

What are the THREE different types of materials that strike-off plates are made of?

A

1) Metal
2) Plastic
3) Glass

19
Q

What is the MINIMUM thickness for a METAL strike-off plate?

A

1/4 inch

20
Q

What is the MINIMUM thickness for a PLASTIC strike-off plate?

A

1/2 inch

21
Q

What is the MINIMUM thickness for a GLASS strike-off plate?

A

1/2 inch

22
Q

How much WIDER must the strike-off plate than the diameter of the density measure

A

2 inches

23
Q

__ lbs +- 0.5 lbs

What is the mallet size required for a 1/2 ft3 measure AND SMALLER?

A

1.25 lbs +- 0.5lbs

24
Q

__ lbs +- 0.5 ;bs

What is the mallet size required for a LARGER THAN 1/2 ft3 ​measure?

A

2.25 lbs

+- 0.5 lbs

25
Q

Rodding, Vibration, or Both?

What method of consolidation must be used when measuring a slump of >3 inches?

A

Rodding

26
Q

Rodding, Vibration, or Both?

What method of consolidation must be used when measuring a slump between 1 inch and 3 inches?

A

Vibration OR Rodding

27
Q

Rodding, Vibration, or Both?

What method of consolidation must be used when measuring a slump of <1 inch?

A

Vibration

28
Q

Do you wet sieve for denisty?

YES OR NO?

A

NO

29
Q

What is the rodding procedure for a density measure of 1/2 ft3 or smaller?

A

Rod each layer 25 times

30
Q

What is the rodding procedure for a density measure of 1 ft3?

A

Rod each layer 50 times

31
Q

1 time for each __ in^2 of surface area

What is the rodding procedure for a density measures of larger than 1 ft3?

A

Rod each layer: 1 time for each 3 in2 of surface area

32
Q

3 – when rodding –> __ when vibrating

What is the amount of lifts when rodding vs. when vibrating?

A

3 – lifts when rodding

2 – lifts when vibrating

33
Q

When vibrating a measure for density – at how many DIFFERENT points do you insert the vibrator?

A

3 DIFFERENT points

34
Q

_/8 inch

How much OVER the lip of the measure do you want your concrete to be?

(Inch)

A

1/8 inches

35
Q

What do you do if you strike-off your measure and you DO NOT HAVE ENOUGH CONCRETE in your measure?

A

You MUST empty the measure and re-fill again

36
Q

2/__ of measure

When sawing excess concrete off of measure – how far onto the plate do you place the strike-off plate onto the measure?

(In Fraction)

A

Across 2/3 of the measure

37
Q

Back/Forward/Clean

Describe the strike-off procedure for density measure in 3 STEPS?

A

1) Place plate 2/3 onto measure and SAW BACK
2) Place place 2/3 onto measure and SAW FORWARD
3) Clean outside of the measure

CMEC ACI WORKBOOK (11 decks)

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