Cold In-Place Recycling

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Primary Resource

Before creating a specification for your CIR project, review the ARRA recommended guidelines for resources in design, testing, quality control, measurement and payment procedures for your project. 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 CIR best practice guidelines for construction are contained in CR101 and recommended quality control checks are contained in CR301. As General rules of thumb, follow the below points and recommendations:

  • Check depth of milling at available longitudinal joints
  • Verify maximum size of RAP
  • Check the application rate of bituminous recycling agent by evaluating the mass of recycled material against the volume of recycling agent used for a single tanker.
  • For foamed asphalt, check the temperature of the asphalt before connecting a tanker to the recycling unit or mixer.
  • For foamed asphalt, verify the expansion ratio and half-life using the test nozzle on the recycling unit or mixer.
  • Verify application rate of dry additives either volumetrically or by using a standard “canvas patch” test, or similar procedure.
  • Verify application of additives applied by slurry using the consumption of additive (and water) obtained from the computer that controls the slurry mixing unit.
  • Determine percent compaction by comparing the in-place density to the target density established in the control strip. If the uniformity of the mixture changes significantly, re-establish the target density.
  • With emulsified asphalt recycling agent after a 3-day minimum cure, consider rerolling when the pavement temperature exceeds 80 F (27 C) to reduce air voids.
  • Check surface tolerance with a 10-foot (3-m) straight edge utilizing a wedge ruler that can slide between the pavement/straight edge interface to accurately measure the gap.

Additional Resources

For additional tools and example specifications, see the assembled list below. Please keep in mind, these specifications are provided as guidelines for your education. ARRA recommends that each agency customize each specification for issues and concerns unique to your area, climate and conditions.

United States

 

Canada