Module 3-4
Cold Milling Cold Milling
Learning Objectives Describe the cold milling process
Describe the characteristics of typical milling equipment
Describe typical applications of cold milling and where it is best applied
Describe design and construction issues
Introduction Revolutionized HMA removal,
leveling and overlay preparation
Considerable changes over the last 20 years
Definitions Cold milling - removal of pavement
surface using drum-mounted carbide steel cutting bits
Diamond grinding Restore ride Improve friction Not to remove material
Grooving – resist hydroplaning
Cold Milling Equipment
Purpose and Application Primary use on HMA
Overlay Recycling Reconstruction
Emerging use on PCC
Full lane to partial lane width
Partial depth to full depth removal
How does your State use cold milling? Removal of rutting
Restoration of curb line
Restoration of cross slope
Restoration of surface friction
Mass removal of HMA
Roughened surface for improved bond between layers
Limitations and Effectiveness Surface texture produced by milling
is a function of: Carbide bit spacing and condition Depth of cut Rotational speed of head Speed of travel
Design Considerations Resulting surface profile
Skid resistance
Pavement removal and surface profiling
Maintain bridge clearance and curb reveal
Construction Considerations Pavement to be resurfaced
Standard head with normal carbide bits
Standard line and grade requirements
Pavement surface to be turned over to traffic Special heads with more carbide bits Smoothness and grade requirements
in line with HMA wearing course
Construction Considerations How will grade be controlled?
Ski, string line, laser, other
Will ride quality be measured on the milled surface? Profilograph, profiler, none
Poor Milled Surface
Special Multiple Tooth Attachments
Special Multiple Wrap Drum
Review What are typical characteristics of
milling equipment?
Where is cold milling best applied?
What construction and design issues should you be aware of?
Key References Collura, J., T. El-Korchi, K. Black, M.
Chase, and L. Jin. 1997. Guidelines for Ride Quality Acceptance of Pavements, Final Report. New England Transportation Consortium, Worcester Polytechnic Institute, Worcester, MA.
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