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Laboratory and Field Performance of Recycled Aggregate Base in a Seasonally Cold Region

This workshop presents the results of a study on the performance of recycled aggregate base in a seasonally cold region, focusing on freezing point depression, resilient modulus, frost depth, and freeze-thaw cycle prediction.

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Laboratory and Field Performance of Recycled Aggregate Base in a Seasonally Cold Region

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  1. 2018 Pavement WorkshopMay 23-24, 2018 Laboratory and Field Performance of Recycled Aggregate Base in a Seasonally Cold Region Bora Cetin Assistant Professor Iowa State University Tuncer Edil & Ali Soleimanbeigi Professor Emeritus / Research Associates University of Wisconsin-Madison + 46 Associate Members

  2. OUTLINE • Problem Statement/Introduction • Objectives • Materials & Methodology • Results • Freezing Point Depression & Freezing Temperatures • Resilient Modulus • Frost Depth & Freeze-Thaw Cycle Prediction • Elastic Modulus • Conclusions • Acknowledgements

  3. PROBLEM STATEMENT Heaving Potholes

  4. PROBLEM STATEMENT Frost Action – Alligator Cracking

  5. CLIMATIC ZONES • Six climatic regions in the United States for pavement design

  6. OBJECTIVES Primary Goals: • Stiffness of recycled and natural aggregates • Freeze point depression • Freezing temperature • Prediction of freeze-thaw cycles • Prediction of frost depth Base Layer

  7. MATERIALS Recycled Concrete Aggregate (RCA) Recycled Asphalt Pavement (RAP) Natural Aggregate (Class 5)

  8. MATERIALS

  9. MATERIALS

  10. MATERIALS

  11. METHODS • Materials were compacted at optimum moisture content Thermocouples

  12. FREEZE-THAW PROCEDURE • Freeze-thaw cycles numbers: 0, 5, 10, 20 • Freeze-Point Depression Tests: • Determine the freezing temperature Freeze-Thaw Procedure 1-D

  13. RESILIENT MODULUS-AASHTO T-307 Vertical Stress Vertical Deformation • Resilient Modulus (MR) • Stiffness • Durability • Test & Compaction Procedure D: 6 inches H: 12 inches Confining Pressure

  14. FALLING WEIGHT DEFLECTOMETER

  15. FIELD SENSORS Thermocouples Moisture Sensors

  16. RESULTS Freezing Point Depression Tests

  17. RESULTS Summary of Freezing Temperatures • Based on the results of freeze-point depression tests, all samples were frozen at -15˚C.

  18. RESULTS Laboratory Resilient Modulus Tests (No Freeze-Thaw)

  19. RESULTS Laboratory Resilient Modulus Tests (After Freeze-Thaw)

  20. RESULTS Temperature RCA

  21. RESULTS Freeze-Thaw Cycles/Year

  22. RESULTS Cumulative Freeze-Thaw Cycles

  23. RESULTS Modulus After Freeze-Thaw Cycles

  24. RESULTS Modulus vs Moisture Content

  25. RESULTS Laboratory and Field Modulus After Freeze-Thaw Cycles

  26. CONCLUSIONS Laboratory Tests • Stiffness changes slightly after 5 freeze-thaw cycles based on the laboratory tests • RCA Modulus Freeze-Thaw Cycles • Total modulus reduction: • RAP ~ 20% • Natural Aggregate ~ 60% over 20 F-T cycles

  27. CONCLUSIONS Field Tests • Elastic Modulus Freeze-Thaw Cycles • RCA & RAP > RCA Blend & Natural Aggregate • Elastic Modulus Moisture Content • Laboratory Modulus = Field Modulus except RCA

  28. Acknowledgments • Minnesota Department of Transportation • MnROAD (Benjamin Worel) • Recycled Materials Resource Center (RMRC) at the University of Wisconsin

  29. Thank You

  30. RESULTS

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