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Block 18 Placement 13

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Block 18 Placement 13

  1. 1. Senior/Graduate HMA Course Placement of HMA MixesConstruction Placement 1
  2. 2. Safety - First, Last and Always... Don’t depend on drivers to avoid you. Play it safe. Watch your back and your buddies.Construction Placement 2
  3. 3. Tractor Hopper Depth Crank Screed Push Rollers Tow Point Conveyor Augers Side Arms sConstruction Placement 3
  4. 4. AUGER CONVEYOR TRACTOR HOPPER DEPTH CRANK SIDE ARMPUSH ROLLER TOW POINT SCREED Construction Placement 4
  5. 5. Tractor UnitConstruction Placement 5
  6. 6. Construction Placement 6
  7. 7. Push Roller Truck HitchConstruction Placement 7
  8. 8. Truck hitch engagedConstruction Placement 8
  9. 9. Construction Placement 9
  10. 10. Construction Placement 10
  11. 11. Construction Placement 11
  12. 12. Construction Placement 12
  13. 13. Construction Placement 13
  14. 14. Construction Placement 14
  15. 15. Construction Placement 15
  16. 16. Construction Placement 16
  17. 17. Material Flow Hopper Wings Proportional Feed Control Slat Conveyors Hopper Gates Augers Screed PlateConstruction Placement 17
  18. 18. Operational Principles of theScreed • Self-leveling Concepts • Screed Response versus Distance • Forces Acting on a ScreedConstruction Placement 18
  19. 19. Self Leveling - Rubber Tired Paver Line of Pull Rear Drive Tires Front Bogie WheelsConstruction Placement 19
  20. 20. L Direction of Paving Screed Path 87% 96% 98% 99% 63% Step Amplitude = 100% Tow Point Path 0 1L 2L 3L 4L 5L 6L L = Leveling Arm Length Detail of Screed PathConstruction Placement 20
  21. 21. 1 inch movement at Tow Point 1/8 inch movement at Leading Edge of ScreedConstruction Placement 21
  22. 22. Main Forces Acting on Screed 1. Speed of Paver 2. Head of Material - Shear resistance 3. Angle of Attack 4. Other Forces – Pre-compaction – Screed WeightConstruction Placement 22
  23. 23. Screed Depth Crank F3 Tow Point Pivot Point F2 F1Construction Placement 23
  24. 24. Correct Depth of Mat Maintained Constant Head of Material Volume Screed Rises Due to Excess Material Forced Under Nose of Screed Head of Material Volume Too High Screed Settles Due to Inadequate Supporting Material Head of Material Volume Too LowConstruction Placement 24
  25. 25. Auger Auger Correct Overloaded Underloade Elevation dConstruction Placement 25
  26. 26. Travel Angle of AttackConstruction Placement 26
  27. 27. Construction Placement 27
  28. 28. HOT STOP Concept• If constant material flow cannot be maintained, before HMA mix drops in hopper below gates...• “Hot Stop” the paver as quickly as possible• Wait for next truck• Pick up truck on run and resume speed as quickly as possible.Construction Placement 28
  29. 29. Screed Control Systems • Who’s Responsible for Changes • Sticking the Mat • Manual Controls • Automatic ControlsConstruction Placement 29
  30. 30. Construction Placement 30
  31. 31. Pavement Profile Direction of PavingConstruction Placement 31
  32. 32. L Direction of Paving Screed Path 87% 96% 98% 99% 63% Step Amplitude = 100% Tow Point Path 0 1L 2L 3L 4L 5L 6L L = Leveling Arm Length Detail of Screed PathConstruction Placement 32
  33. 33. Construction Placement 33
  34. 34. Construction Placement 34
  35. 35. Types of Grade Reference • Stringline • Mobile reference • Joint matching shoe • Sonic sensor • LaserConstruction Placement 35
  36. 36. Construction Placement 36
  37. 37. Construction Placement 37
  38. 38. Construction Placement 38
  39. 39. Construction Placement 39
  40. 40. Construction Placement 40
  41. 41. Construction Placement 41
  42. 42. Grade Sensor - Side Arm MountConstruction Placement 42
  43. 43. Grade Sensor - Screed End MountConstruction Placement 43
  44. 44. Construction Placement 44
  45. 45. Ultrasonic Grade SensorConstruction Placement 45
  46. 46. Balancing Production HMA Paving FacilityTrucking Compaction Construction Placement 46
  47. 47. QUESTIONS ?Construction Placement 47

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