Importance of Level Control

Level control poles:

A fool-proof method for controlling levels on recycling projects is vital. This simple system, with derivatives used worldwide, is based on a series of ‘level control poles’ installed at a constant intervals (20 m or 65 ft) on both sides of the lane. The final surface elevations are then marked on these poles (using nails and tape) with a constant measurement or “dip” from a spanned stringline to the final road level.

The measurement or dipping can be used to determine:

  • The shape of the existing road.
  • The bottom of the cut horizon behind the recycler.
  • Final levels to be cut by a grader.

Final level:

Once recycling and initial compaction has been completed, the grader with a “dip” team can use the level control poles to cut away all steps and indentations in the surface. Material can then be placed back and compacted. The level control pegs can then be used to cut final levels of the layer.

Cut depth:

Cut depth is measured directly behind the recycler by pushing a T-bar into the loose material (not in wheel paths of the recycler) and measuring down from the stringline. The depth should be measured on both sides of the cut at 20 m intervals.

Importance of measuring the cut depth:

  • Ensure the full depth of material is recycled, avoiding
    an interlayer of untreated material.
  • Avoids recycling too deep, leading to an under application of bitumen.
  • Recycling horizon is parallel to the final road level, ensuring a consistent layer thickness.
  • Required layer thickness is achieved.

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