Road construction equipment, paver and bitumen sprayer

Equipment for road construction

Paver (finisher)

  tipper -> [hopper] -conveyor-> [auger] -> [screed]
            (receives hot mix)   spreads    levels, compacts

Functions: receives hot mix from trucks, spreads it evenly across the width, and gives the specified thickness, camber and level, with initial compaction by the vibrating screed. Sequence of operation:

1. Clean the base and apply a tack coat.
2. Set the screed height (thickness) and the guide wire or sensors; pre-heat the screed.
3. The tipper backs to the paver, which pushes it forward as hot mix is discharged to the hopper.
4. The conveyor feeds the mix to the augers, which spread it in front of the screed.
5. The screed levels and compacts the mat as the paver moves forward at a steady speed.
6. Rollers (breakdown, intermediate, finish) follow immediately to compact.

Bitumen sprayer (distributor)

  [Insulated tank + burner]  pump  spray bar
  =========truck========== |||||||||||
                           (nozzles spray hot bitumen)

Functions: sprays bitumen (tack coat, prime coat, surface dressing binder) uniformly over the road surface at a controlled rate (kg/m$^2$) and temperature. Sequence:

1. Heat the bitumen in the tank to the spraying temperature.
2. Clean the base; set the spray bar height and the nozzles.
3. Pump the bitumen through the spray bar as the truck moves at a uniform speed.
4. Check the rate of application; avoid overlap or gaps at joints.
5. Spread chippings immediately (for surface dressing) and roll.