12–69. On a vibrating type of screed, the compactive  force  can  be  generated by  hydraulic  motors,  rotating shafts  with  eccentric  weights,  or by  electric  vibrators. 1. True 2. False 12-70. When an adjustment is made to the screed control of a paver, the effect  of  the  adjustment  can  be seen after the paver travels what distance? 1. Several  yards 2. Several  inches 3. Several  feet 4. Several  meters 12-71. Poor pavement smoothness is most likely a result of which of the following operator errors? 1. Paving  too  fast 2. Over  thickness  control 3. Paving  too  slow 4. Overcompaction 12-72. The screed plates on an asphalt paver have a total of how many screed  crown  adjustments? 1. One 2. Two 3. Three 4. Four 12–73. For paving operations, a paver screed should be heated at what time ? 1. During  the  paving  operation 2. Before  the  paving  operation 3. Only  sometimes  during  the paving  operations 4. Only  when  asphalt  materials are under the screed 12–74. Which  of  the  following  components are  commonly  used  screed  accessory attachments? 1. Screed  extensions 2. Cutoff  shoes 3. Bevel  end  plates 4. All of the above 12-75. The  required  tonnage  of  hot-mix asphalt for a project is 1500 tons. The screed of the paver is set at 8 feet, and the depth of asphalt is 4 inches. What is the amount of asphalt that can be laid per  hour? 1. 80.46 tons 2. 100.62  tons 3. 128.35 tons 4. 192.72 tons 96