Cold Planing & Micro Milling

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Before creating a specification for your CP project, review the ARRA recommended guidelines for cold planing CP101 and micro milling CP102. There are many factors to consider after reviewing the ARRA guidelines, and your project may need slight adjustments to meet the localized conditions of your project.

Helpful Guidelines

Complete CP best practice guidelines for milling and micro milling are contained in CP101 and CP102, respectively. As General rules of thumb, follow the below points and recommendations:

  • Check depth of milling every 100 feet behind the cold planer. Tolerances vary due to application but for a typical mill and overlay a tolerance of ± 3/16 inch (5 mm) is usually allowed. 
  • Check grade, if specified. Typical tolerance for grade is ± 3/16 inch (5 mm). 
  • Check cross-slope, if specified. Typical tolerance for cross-slope is ± 0.2%.
  • Check smoothness of the milled surface, if specified, with a 10 foot (3 m) straightedge. Typical tolerance is ± 1/4 inch (6 mm). Smoothness is often specified on the overlay, expressed as International Roughness Index (IRI), Mean Roughness Index (MRI), Profile Index (PI) or Ride Number (RN). 
  • CP machines cannot guarantee specific RAP gradation bands or maximum size.
  • Check surface texture, if specified, using a sand patch test.

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