Astm C138/c138M Density, Yield And Air Content Of Concrete

Front 1

The diameter of the tamping rod used in this test method is

Back 1

5/8'' +- 1/16'' (2mm)

Front 2

What is required shape of the tamping end of the rod?

Back 2

rounded / hemispherical

Front 3

What is the required minimum frequency of the vibrator used in this test method?

Back 3

7000

Front 4

The outside diameter or side dimension of the vibrating element shall be at least _____ but not greater than ____

Back 4

.75'' and 1.5''

Front 5

A plastic container can be used for the measure in this method. T or F

Back 5

True

Front 6

What is the minimum thickness of a metal strike-off plate?

Back 6

1/4''

Front 7

What is the minimum thickness for a glass or acrylic strike off plate?

Back 7

1/2/''

Front 8

What is the specified weight of the mallet used on measures that are 0.5ft^3 [14L] or smaller?

Back 8

1.25 +- .5lb

Front 9

Measures other than air meter bowls used for this test must conform to ASTM

Back 9

C29

Front 10

Air meter bowls used for this test must conform to ASTM _____ and be calibrated for volume according to ASTM _____

Back 10

C231 and C29

Front 11

The concrete sample must be obtained in accordance with what ASTM method?

Back 11

C-172

Front 12

What method of consolidating must be used when the slump is greater than 3 inches? (75mm)

Back 12

Rodding

Front 13

What method of consolidating must be used when the slump is less than 1 inch (25mm)

Back 13

Vibration

Front 14

if rodding is the method of consolidating used, the measure must be filled in how many layers?

Back 14

3

Front 15

For a measure of 0.5ft^3 [14L] what is the required number of strokes of the tamping rod for consolidating of each layer?

Back 15

25

Front 16

When rodding the middle and top layers, the tamping rod should penetrate into the layer below approximately

Back 16

1''

Front 17

If vibration is the method of consolidating, the measure must be filled in _____ approximately equal layers

Back 17

2

Front 18

If, after consolidating of the final layer, the concrete level is 1/2 inch (13mm) above the top measure what should be done?

Back 18

Remove excess with scoop

Front 19

After consolidating of the final layer, an excess of concrete ______ above the top of the measure is considered optimum

Back 19

1/8''

Front 20

After completing the strike off procedure what must be done before weighing the measure and sample?

Back 20

clean measure of any excess material