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2022 Spring Educational Workshop presentation on QA for CIR and CCPR

California Asphalt Pavement Association
28. Mar 2023
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2022 Spring Educational Workshop presentation on QA for CIR and CCPR

  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
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