2018 Pavement Workshop May 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

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

PROBLEM STATEMENT Heaving Potholes

Frost Action – Alligator Cracking PROBLEM STATEMENT Frost Action – Alligator Cracking

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

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

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

MATERIALS

MATERIALS

Asphalt/Mortar Content (%) MATERIALS MATERIAL Natural Aggregates RCA RCA Blend RAP Wopt (%) 8.9 11.2 8 6.7 γdmax (kN/m3) 20.1 19.3 21.4 20.7 Absorption (%) - 15 1.8 Asphalt/Mortar Content (%) 55 7.1 Impurities (%) 0.25 0.87 0.36 0.06 USCS GW-GM SW SP AASHTO A-1-b A-1-a

METHODS Materials were compacted at optimum moisture content Thermocouples

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

RESILIENT MODULUS-AASHTO T-307 Resilient Modulus (MR) Stiffness Durability Test & Compaction Procedure Vertical Deformation Vertical Stress Confining Pressure H: 12 inches D: 6 inches Resilient modulus test is a repeated-load trixial test. It is a non-destructive test. It is used to characterize the base materials under loading conditions that are not resulted in failure of the pavement system.

FALLING WEIGHT DEFLECTOMETER Parameters FWD Number of receivers 9 Receiver spacing (m) 0.15 to 0.31 Total length (m) 1.38 Distance from the source to the first receiver (m)

FIELD SENSORS Thermocouples Moisture Sensors

Freezing Point Depression Tests RESULTS Freezing Point Depression Tests

RESULTS Summary of Freezing Temperatures MATERIALS Freezing Point Depressions (˚C) Freezing Temperature (˚C) Natural Aggregate -5.2 -12 RCA -10 RAP Based on the results of freeze-point depression tests, all samples were frozen at -15˚C.

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

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

RESULTS Temperature RCA

Freeze-Thaw Cycles/Year RESULTS Freeze-Thaw Cycles/Year

Cumulative Freeze-Thaw Cycles RESULTS Cumulative Freeze-Thaw Cycles

Modulus After Freeze-Thaw Cycles RESULTS Modulus After Freeze-Thaw Cycles

Modulus vs Moisture Content RESULTS Modulus vs Moisture Content

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

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 Read the slides

CONCLUSIONS Field Tests Elastic Modulus Freeze-Thaw Cycles RCA & RAP > RCA Blend & Natural Aggregate Elastic Modulus Moisture Content Laboratory Modulus = Field Modulus except RCA Read the slides

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

Thank You

RESULTS