Practice C31: Making and Curing Concrete Test Specimens in the Field Flashcards

1
Q

ASTM Method gives standardized requirements for ___, ___, ___, and ___ of test specimens.

A

Making, curing, protecting, transporting

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2
Q

For cylinders with a diameter of 6 inches or greater, the tamping rod must be a round, straight, steel rod with a diameter of ____.

A

5/8 inches

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3
Q

The minimum frequency of an internal vibrator used in this procedure is ____.

A

9000 vibrations per minute (150 Hz)

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4
Q

The container for obtaining the concrete sample used in this procedure can be a ___, ___, or ___.

A

Metal pan, wheelbarrow, flat, clean, nonabsorbent mixing board

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5
Q

A 6 by 12 inch cylinder mold can be used for concrete containing aggregate with particles not exceeding ____ in size, without the need for wet sieving the concrete.

A

2 inches

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6
Q

The sample of concrete used in molding test specimens must be obtained in accordance with what ASTM standard?

A

C172

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7
Q

When strength specimens are to be made, what three other tests must be made?

A

Slump, air content, temp

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8
Q

After molding test specimens, you should wait 2 hours before moving them to the location of initial storage. T/F

A

False - move immediately

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9
Q

The supporting surface on which specimens are stored shall be level within ____.

A

1/4 inch per foot

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10
Q

For concrete with a slump of less than 1 inch, the test specimens must be consolidated by _____.

A

Vibration

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11
Q

If the concrete is to be consolidated by vibration, a standard 4 x 8 inch cylinder mold must be filled in ___ equal layers.

A

2

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12
Q

When rodding a standard 6 by 12 inch cylinder, each layer must be rodded ___ times.

A

25

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13
Q

When rodding each upper layer of concrete in a cylinder, the tamping rod should penetrate into the underlying layer by about ___.

A

1 inch

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14
Q

When using an internal vibrator to consolidate a 6x12 inch compressive strength test specimen, the vibrator must be inserted at ___ different point for each layer.

A

2

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15
Q

When consolidating a flexural strength test specimen by rodding, rod one stroke for each ___ of top surface area.

A

2 square inches

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16
Q

When internal vibration is used to consolidate a standard flexural strength test specimen, the technician should insert the vibrator at intervals not exceeding ___ along the center line of the beam.

A

6 inches

17
Q

Concrete mixtures with specified strengths of 6000 psi or greater shall have an initial curing temp between ______.

A

68 and 78 degrees F

18
Q

Up to 48 hours after molding, text specimens that are to be standard cured shall be stored in a temp range between ____ to _____.

A

60 and 70 degreees F

19
Q

Upon completion of initial curing, the test specimens may be left in their molds and sealed in plastic bags. T/F

A

False - specimens should be demoled and placed in water storage tanks or moist rooms with free water at a temp of 73.5 +- 3.5 degrees F