Section 4

Question 1

the length of the tamping rod used in this test method is

Answer 1

at least 4 inches taller than the height of the measure but no more than 24 inches

Question 2

what is the required shape of the end of the tamping rod

Answer 2

rounded to a hemispherical tip

Question 3

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

Answer 3

9000 vibrations per min

Question 4

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

Answer 4

.75 and 1.5 inches

Question 5

what material is the measure made of

Answer 5

typical medal

Question 6

what is the min thickness of the metal strike off plate

Answer 6

1/4 inch

Question 7

what is the min thickness for glass or acrylic strike off plate?

Answer 7

1/2 inch

Question 8

what is the specified weight of the mallet used on measures that are 1/2 cf or smaller

Answer 8

1.25 lbs plus or minus 1/2 lbs

Question 9

what method of consolidation must be used when the slump is greater than 3 inches

Answer 9

rodding

Question 10

what method of consolidation must be used when the slump is less that 1 inch

Answer 10

vibration

Question 11

if rodding method is used for unit weight the measure must be filled in _____ layers

Answer 11

3

Question 12

for a measure of 1/2 cf what is the required number of strokes of the tamping rod for consolidation of each layer ?

Answer 12

25

Question 13

when rodding top and middle section how much should the rod penetrate into the level below?

Answer 13

1 inch

Question 14

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

Answer 14

2

Question 15

If, after consolidation of the final layer, the concrete level is 1/2 inch above the top of the measure what should be done?

Answer 15

remove enough concrete to ensure you have over filled the measure to approximately 1/8 inch above the top of the measure

Question 16

after completing the strike off procedure what must be done before weighting the measure and sample?

Answer 16

clean off any excess concrete

Question 17

calculate the density of the following concrete : volume = .504 cf , mass empty container = 19.6 lbs, mass of measure plus concrete= 92.1

Answer 17

143.8 lbs/cf

Question 18

Yield calculation: the total mass of all materials batched was 27,300 lbs (12,383 kg). Using the density of the concrete as determined in question 17, calculate yield in cf, in cy, and in m^3

D=143.8

Answer 18

yield = 189.8 cf, 7.031 cy, density of this concrete is 2305 kg/m^3 so yield = 27,300/2305=5.37 m^3

Question 19

relative yield calculation: the volume designed for the batch Yd was 7 cy. Knowing that the yield was A. 189 cf, 7 cy, and 5.4 m^3 determine the relative yield

Answer 19

1,1,1

Question 20

Air content calculation - your air meter has been damaged in transit, to the job site. you do however know the theoretical density that was determined in the lab = 151.4 lbs/cf. Using the following density of 143.8 lbs/cf find the air content using density in lbs/cf

Answer 20

(151.4-143.8)/151.4=5%