Cold In-Place Recycling

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Application Sequence

  1. Clean roadway of objectionable materials and perform any necessary patching or pre-milling.
  2. Corrective Aggregate and/or active filler, if required, are spread on the road ahead of the recycler.
  3. The recycling train mills up 2-5 inches (50 – 125 mm) of the existing asphalt pavement.
  4. The millings are sized.
  5. The additives and recycling agent (emulsified asphalt or foamed asphalt) are added and mixed with the RAP.
  6. The recycled mix is either placed in a windrow on the pavement and placed into a paver using a windrow elevator or placed directly into the paver hopper.
  7. The mat is compacted by heavy pneumatic and double drum vibratory rollers.
  8. The road is opened to traffic soon after compaction is achieved (within hours).
  9. A fog seal and blotter sand are applied if raveling is a concern.
  10. The recycled mixture is allowed to cure for a minimum of three days.
  11. With emulsified asphalt recycling agent, consider rerolling when the pavement temperature exceeds 80 F (27 C) to reduce air voids.
  12. A surface course is applied after the recycled mixture has cured.

Application Guidelines


  • If required, a control strip should be placed in conditions similar to those that are expected to occur during the construction 


  • Spread ahead of the train in a controlled way
  • Canvas Patch test or similar can verify application rate


  • Measure cutting depth along longitudinal joint
  • Milling machine should cut to the desired depth (constant or variable by ski). Uncontrolled variations such as rising/dipping could mean a hydraulic problem


  •  Variable thickness of existing asphalt can lead to breakthroughs and affect smoothness


  • Particles should look evenly coated
  • Particle size should meet specification requirements (especially top size)
  • No blobs or stringers of undispersed recycling agent 
  • No segregation in windrow or in paver


  • Uniform look with no major segregation, streaks, fat spots
  • Placed to consistent depth
  • The mat will look coarser than a typical hot mix mat. This is normal, as the CIR mix has higher voids and larger aggregate max size than a dense graded asphalt. With rolling traffic, the surface of the CIR will knead together and look tighter
  • At first, the mat may look brown. Some emulsified asphalts have a brownish color before the emulsion breaks and turns black. This happens soon after placing
  • Check for slope/crossfall directly behind the paver


  • Establish rolling pattern via control strip to achieve target density
  • Ensure roller drums are clean and not covered with picked up material
  • Roller skirts are not needed as the mix temperature is close to ambient
  • Rollers should not be stopped on the fresh mat
  • For foamed asphalt mixes, keep the water content at optimum moisture content to aid compaction
  • Check compaction with nuclear gauge
  • Check slope with straightedge/smart level after final rolling


  • Control traffic to keep stopped traffic off the fresh mat
  • Traffic should be piloted slowly on the fresh mat to prevent ravelling
  • If fog seal is used to prevent raveling, apply sand blotter and/or wait for the fog seal to cure before allowing traffic
  • Watch for early signs of rutting, ravelling, or other distresses, and notify the Contractor immediately if a problem persists