At the California Asphalt Pavement Association (CalAPA) Spring “Technical Tune-Up” Educational Workshop held April 5, 2022 in Brea, a presentation titled "Developing a Successful QA Program for Cold in-place Recycling (CIR) and Cold Central Plant Recycling (CCPR)" was delivered by Fernando Aragon, P.E., G.E., Principal Engineer, Aragon Geotechnical, Inc. Successful CIR implementation requires effective QC testing by the contractor and acceptance testing by the Owner/Agency. Learn the key components for both of these testing programs that make up a successful QA program. Learn what the new specifications mean for testing and common mistakes to avoid during the construction of CIR and CCPR projects.

1. Developing a Successful QA
Program for CIR and CCPR
Fernando Aragon, P.E., G.E.
Aragon Geotechnical, Inc.

2. Introduction
• CCPR/CIR
• Sampling
• Mix Design
• Field Testing
• Lab Testing
• Specifications
• Common Mistakes

3. What is Cold
Central Plant
Recycling?
1. We mill Reclaimed Asphalt Pavement (RAP) from existing
roadways within the project limits and stockpile in the
general vicinity of the project.
2. We then size the stockpiled RAP to a specified maximum
size.
3. Next, we take the properly sized RAP and blend it with a
bituminous recycling agent (emulsified or foamed asphalt),
water and other additives (cement, lime or corrective
aggregate) to produce a recycled asphalt mixture.
4. Finally, we place and compact the recycled asphalt mixture
in accordance with the plans and specifications.

4. What is Cold In-place
Recycling?
1. We mill and pulverize (thereby,
reclaiming) a portion of the existing
asphalt pavement to the length, depth
and width as shown on the plans.
2. We then size the Reclaimed Asphalt
Pavement (RAP).
3. Next, we blend the RAP with a
bituminous recycling agent (either
foamed asphalt or emulsified asphalt),
water and other additives (cement,
lime, corrective aggregate) to produce
a recycled asphalt layer.
4. Finally, we place and compact the
recycled asphalt layer in accordance
with the plans and specifications.
Cement Spreading Unit
Full Lane Mill
Recycling Unit
Recycling Agent

5. CIR/CCPR vs HMA
• Not that dissimilar to HMA
Testing.
• Final Air Voids is between 9%
to 15% - Plan accordingly.
• It is cold! No need to heat
the paver.
• There is water in emulsion
and as part of the foam
process.
• Emulsion requires moisture
check and supplement
compaction.
• Foamed typically requires
moisture check.

6. Sampling
Key Objectives:
• Verifying Existing Conditions
• Subgrade Stability
• Adequate Pavement
Thickness
• Presence of Paving Fabric
• Is the current pavement
experiencing instability?
• Obtaining representative material
• Observing & Documenting
Surroundings
• Presence of low trees and/or
shade (can slow down the
curing)

7. Mix Design
• Optimum Emulsion/Foamed Content
• Additive Requirements
• Indirect Tensile Strength or Marshall Stability
• Existing Pavement Properties

8. Quality Control – Field
Testing
• Daily Break-over Curve
• Minimum 1 per day
• Changes with Material & Environment
• 10-ton Steel Drum Vibratory
• 25-ton Pneumatic

9. Quality Control – Field
Testing
• Compaction
• Break over curve established
beginning of day
• New curve if tests fall
outside limits
• 10 tests per lot (a lot is
normally defined as 3,000
square yards of production)
• Each individual test to fall
within 95% to 105% of break
over density
• The average of each lot to fall
within 97% to 103%

10. Quality Control – Lab
Testing
• Sieve analyses
• To determine particle sizes.
• Maximum Theoretical Gravity (RICE)
• To determine Void Ratio. For information
only.
• Indirect Tensile Strength
• Mix Design for Foam Asphalt
• Construction Testing mostly only for CT
• Marshall Stability
• Mix Design for Emulsion
• Construction Testing mostly only for CT

11. Specifications
• Special Provision Specifications
per project. Well established.
• Caltrans Test Method 315 – in
data collection phase
• Greenbook – In final review.

12. Common Mistakes
• Street selection
• Not a magic fix for all streets
• Have good preliminary design information
• Soft Subgrade
• Have enough existing pavement to recycle
• Understand the grade control, e.g., a crown,
matching grade, quarter-crown syndrome
• Incorrect selection of specifications
• Can add unwanted costs to project.
• Environmental Conditions
• Not performed during wet or rainy conditions
• Minimum outside temperature of 50 °F
• Sunlight helps in the recycling, curing and
compaction.

13. More Common Mistakes
• Rollers
• Follow established rolling pattern
• Do not stop on mat
• Use clean water, no release agents
• Raveling in cross traffic, and high shear areas
• Recycling done at least 2 hours before end of shift (allow time for other tasks)
• Minimize Handwork of Mat

14. Conclusion
Have
Have appropriate
contingency in place
as part of the
project
specifications.
Design
Design your projects
with changer order
avoidance in mind.
Get enough
information.
Use
Use the appropriate
specifications for
your project.

15. Questions