5-51. A total of how many cubic yards of concrete is required for a pad 60 feet in length, by 30 feet in width, with a depth of 4 inches and a waste factor of 10 percent? 1. 24.2 2. 22.0 3. 59.4 4. 65.3 5-52. Batching  by  volume  provides greater accuracy and avoids problems created by the bulking of damp sand. 1. True 2. False 5-53. When mixing concrete in a transit mixer, what is the maximum number of revolutions of the drum at mixing  speed  that  you  should  use? 1. 60 2. 70 3. 90 4. 100 5-54. What is the minimum agitating speed on a transit mixer? 1. 1 revolution per minute 2. 2  revolutions  per  minute 3. 3  revolutions  per  minute 4. 4  revolutions  per  minute 5-55. Concrete  that  is  kept  agitated  can generally  be  placed  within  what maximum  time  period  after  mixing? 1. 3 1/2 hours 2. 2 1/2 hours 3. 1 1/2 hours 4. 1/2 hour 5-56. On a mobile concrete mixer plant, the sand and aggregate are accurately  proportioned  according to  what  measurement(s) 1. By cubic feet of material only 2. By  cubic  yards  of  material only 3. By weight or by cubic feet 4. By weight or by volume 5-57. You are conducting a slump test. Which  of  the  following  results indicate a poor mix? 1. The  concrete  mix  crumbles 2. The  concrete  mix  segregates 3. The  concrete  mix  falls  apart 4. Each of the above 5-58. When working around cement, you should  pay  particular  attention to any rash on your skin because a rash may indicate cement poisoning. 1. True 2. False Learning  Objective:  Describe  the operations of an asphalt plant. 5-59. On a batch plant, the size of a batch varies according to the capacity  of  what  component? 1. The hopper 2. The dryer 3. The  pugmill 4. The  screens 5-60. The  proper  amount  of  aggregates for  asphalt  mixes  is  initially controlled by a uniform flow of the  aggregate  through  what component? 1. Cold-feed   adjustment 2. Hot-feed   adjustment 3. Cold-bin capacity 4. Hot-bin capacity 5-61. The  overloading  of  the  screens with  aggregate  underscores  a  need for control of what factor? 1. Proper  dryer  control 2. Proper   weigh-hopper calibration 3. Proper  cold  feeding 4. Proper  gradation  control calibration 38