NCHRP Web-Only Document 450

Recycled Asphalt Materials: Binder Availability and Its Impact on Mix Performance

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COOPERATIVE RESEARCH PROGRAMS

CRP STAFF FOR NCHRP WEB-ONLY DOCUMENT 450

Monique R. Evans, Director, Cooperative Research Programs

Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program

Amir N. Hanna, Senior Program Officer

Oulimata Khoule, Senior Program Assistant

Natalie Barnes, Director of Publications

Brian Haefs, Associate Director of Publications

Jennifer J. Weeks, Publishing Project Manager

NCHRP PROJECT 09-68 PANEL

Field of Materials and Construction—Area of Bituminous Materials

Stacey D. Diefenderfer, Virginia Transportation Research Council, Charlottesville, VA (Chair)

Ian Anderson, Vermont Agency of Transportation, Barre, VT

Luiza Barros, Texas Materials - a CRH Company, Liberty Hill, TX

Amy J. Beise, North Dakota Department of Transportation, Bismarck, ND

Ashley Buss, Iowa Department of Transportation, Ames, IA

Silvia Caro, Universidad de Los Andes, Bogota, Columbia

Ervin L. Dukatz, Jr., Flyereld Consulting, LLC, La Crosse, WI

Stacy Glidden, Walbec Group (formerly), Greenville, WI

Liz Mensink, Rijkswaterstaat, Deventer, The Netherlands

Brian Pfeifer, Illinois Department of Transportation, Springfield, IL

Jack S. Youtcheff, Jr., FHWA Liaison

AUTHOR ACKNOWLEDGMENTS

The authors acknowledge the feedback provided on certain aspects of the research from several national and international researchers experienced with recycled asphalt materials and binder availability. The authors also acknowledge the asphalt contractors and material suppliers who provided materials for evaluation in this project, as well as the laboratory staff at the National Center for Asphalt Technology at Auburn University (NCAT) and Texas A&M Transportation Institute (TTI) for their assistance and support with laboratory testing activities.

TABLE OF CONTENTS

Chapter 1 Background

1.1 Problem Statement

1.2 Research Objectives

1.3 Organization of the Report

Chapter 2 Research Approach

2.1 Information Gathering

2.2 RBA Method Selection

2.3 RBA Sensitivity Evaluation

2.4 RBA Impact Analysis

Chapter 3 Findings and Applications

3.1 RBA Method Selection Findings

3.2 RBA Sensitivity Evaluation Findings

3.3 RBA Performance Impact Analysis Findings

3.4 RBA Cost Impact Analysis Findings

Chapter 4 Summary and Suggested Research

4.1 Summary

4.2 Suggested Research

References

Abbreviations

Appendixes

Appendix A. Literature Review

Appendix B. State DOT Survey and Responses

Appendix C. Draft Method of Test for Determining the Recycled Binder Availability for Asphalt Mixtures Containing Recycled Asphalt Materials

Appendix D. Draft Method of Test for Determining the Effects of Recycled Binder Availability on Performance Properties of Asphalt Mixtures Containing Recycled Asphalt Materials

Appendix E. Proposed Revisions to AASHTO PP 127, Provisional Standard Practice for Development of Balanced and Durable Asphalt Mixtures with High Recycled Asphalt Materials Contents

Appendix F. Proposed Revisions to AASHTO M 323, Standard Specification for Superpave Volumetric Mix Design

Appendix G. Proposed Revisions to AASHTO R 35, Standard Practice for Superpave Volumetric Design for Asphalt Mixtures

Appendix H. Recommended Process for Incorporating RBA in the Design and Production of Asphalt Mixtures Containing RAM

LIST OF FIGURES

Figure 1. Research Approach

Figure 2. Sample Preparation for Blending Simulation of Virgin and RAM Binders Method (Nazzal et al., 2017)

Figure 3. Modified Contact Blending Analysis of Two-layered Composite Binder Blend Method using Topography AFM Imaging (Huang et al., 2017)

Figure 4. Illustration of Extracted Binder Testing of Coarse-aggregate, Fine-RAP Asphalt Mixture Method (Yu et al., 2017)

Figure 5. Illustration of Ignition Oven Testing of Virgin Asphalt Mixture versus RAP Asphalt Mixture Method (Kaseer et al., 2019)

Figure 6. Illustration of Available and Unavailable Mastic due to RAP Agglomeration (Castorena et al., 2022)

Figure 7. Glass Beads Before and After Mixing

Figure 8. EDS SEM Images at Different Virgin Regions (Castorena et al., 2016)

Figure 9. Evaluation of Candidate RBA Methods using LP-RAP Asphalt Mixtures

Figure 10. RBA Determination Approach for Performance Testing Method

Figure 11. RBA Determination Approach for Glass Beads Method

Figure 12. RBA Testing of Field RAM Asphalt Mixtures for Sensitivity Evaluation

Figure 13. RBA Impact Analysis of High-RAM Asphalt Mixtures

Figure 14. FlexPAVE Simulation Pavement Structure

Figure 15. LCCA Framework for RBA Cost Analysis of High-RAM Asphalt Mixtures

Figure 16. Degree of Agglomeration Results of LP-RAP Samples

Figure 17. IDT Strength Results of LP-RAP Samples

Figure 18. DWT-value Results of LP-RAP Samples

Figure 19. IDEAL-CT CT_Index Results of LP-RAP Asphalt Mixtures: (a) Laboratory 1, (b) Laboratory 2

Figure 20. IDEAL-RT RT_Index Results of LP-RAP Asphalt Mixtures: (a) Laboratory 1, (b) Laboratory 2

Figure 21. RBA Results of LP-RAP Asphalt Mixtures for Glass Beads Method

Figure 22. Pearson Correlation between LP-RAM Sample Characterization Results versus RBA Values Obtained using Glass Beads Method

Figure 23. Degree of Agglomeration Results of Field RAM Samples

Figure 24. DWT-value Results of Field RAM Samples

Figure 25. RBA Results of Field RAM Asphalt Mixtures with Different RAM Types, Sources, and Contents

Figure 26. Correlation between Extracted Binder PGH and RBA Results

Figure 27. Correlation between Degree of Agglomeration and RBA Results

Figure 28. Correlation between DWT-value and RBA Results

Figure 29. RBA Results of Field RAM Asphalt Mixtures with Different Virgin Binders

Figure 30. RBA Results of Field RAM Asphalt Mixtures with Different Virgin Aggregates

Figure 31. RBA Results of Field RAM Asphalt Mixtures with Different Production Temperatures

Figure 32. RBA Results of Field RAM Asphalt Mixtures with and without Laboratory Simulated Silo Storage

Figure 33. HWTT and IDEAL-CT Results of Georgia High-RAP Asphalt Mixtures: (a) PG 64-22 Binder, (b) PG 76-22 PMA Binder

Figure 34. HWTT and IDEAL-CT Results of Wisconsin High-RAP/RAS Asphalt Mixtures: (a) PG 58S-28 Binder, (b) PG 58V-28 PMA Binder

Figure 35. |E*| Master Curves of Georgia High-RAP Asphalt Mixtures: (a) PG 64-22 Binder, (b) PG 76-22 PMA Binder

Figure 36. |E*| Master Curves of Wisconsin High-RAP/RAS Asphalt Mixtures: (a) PG 58S-28 Binder, (b) PG 58V-28 PMA Binder

Figure 37. DTCF Results of Georgia High-RAP Asphalt Mixtures: (a) D^R Parameter, (b) S_app Parameter

Figure 38. DTCF Results of Wisconsin High-RAP/RAS Asphalt Mixtures: (a) D^R Parameter, (b) S_app Parameter

Figure 39. FlexPAVE Simulation Results of Georgia High-RAP Asphalt Mixture with PG 64-22 Binder: (a) Total Fatigue Damage, (b) Top Fatigue Damage, (c) Bottom Fatigue Damage

Figure 40. FlexPAVE Simulation Results of Georgia High-RAP Asphalt Mixture with PG 76-22 PMA Binder: (a) Total Fatigue Damage, (b) Top Fatigue Damage, (c) Bottom Fatigue Damage

Figure 41. FlexPAVE Simulation Results of Georgia High-RAP Asphalt Mixture with PG 64-22 Binder using Adjusted Asphalt Layer Thickness: (a) Total Fatigue Damage, (b) Top Fatigue Damage, (c) Bottom Fatigue Damage

Figure 42. FlexPAVE Simulation Results of Georgia High-RAP Asphalt Mixture with PG 76-22 PMA Binder using Adjusted Asphalt Layer Thickness: (a) Total Fatigue Damage, (b) Top Fatigue Damage, (c) Bottom Fatigue Damage

Figure 43. FlexPAVE Simulation Results of Wisconsin High-RAP/RAS Asphalt Mixture with PG 58S-28 Binder: (a) Total Fatigue Damage, (b) Top Fatigue Damage, (c) Bottom Fatigue Damage

Figure 44. FlexPAVE Simulation Results of Wisconsin High-RAP/RAS Asphalt Mixture with PG 58V-28 PMA Binder: (a) Total Fatigue Damage, (b) Top Fatigue Damage, (c) Bottom Fatigue Damage

Figure 45. FlexPAVE Simulation Results of Wisconsin High-RAP/RAS Asphalt Mixture with PG 58V-28 PMA Binder using Adjusted Asphalt Layer Thickness: (a) Total Fatigue Damage, (b) Top Fatigue Damage, (c) Bottom Fatigue Damage

Figure 46. Material Costs of High-RAM Asphalt Mixtures at A-OBC and V-OBC

Figure 47. Percent Difference in Material Costs of High-RAM Asphalt Mixtures Compared to 25% RAP Asphalt Mixtures at 100% RBA

Figure 48. Percent Difference in Material Costs of High-RAM Asphalt Mixtures Compared to Virgin Asphalt Mixtures

Figure 49. LCCA NPV Results of Georgia High-RAP Asphalt Mixtures: (a) PG 64-22 Binder, (b) PG 76-22 PMA Binder

Figure 50. LCCA NPV Results of Wisconsin High-RAP/RAS Asphalt Mixtures: (a) PG 58S-28 Binder, (b) PG 58V-28 PMA Binder

LIST OF TABLES

Table 1. Critical Review of Existing RBA Methods in Literature

Table 2. Mixture Component Combinations for Field RAM Mix Designs

Table 3. Field RAM Characterization

Table 4. Field RAM Asphalt Mixtures for RBA Sensitivity Evaluation (Experiment 1)

Table 5. Field RAM Asphalt Mixtures for RBA Sensitivity Evaluation (Experiment 2)

Table 6. Field RAM Asphalt Mixtures for RBA Sensitivity Evaluation (Experiment 3)

Table 7. High-RAM Mix Design Summary

Table 8. Mixture Performance Testing for RBA Impact Analysis

Table 9. FlexPAVE Simulation Inputs

Table 10. Costs of Individual Component Materials for High-RAM Asphalt Mixtures

Table 11. RBA Results of LP-RAP Asphalt Mixtures for Performance Testing Method

Table 12. PGH Results of LP-RAP Asphalt Mixtures

Table 13. Aggregate Gradation, Binder Content, and Extracted Binder PG Results of Field RAM Samples

Table 14. Aggregate Gradations of Field RAM Mix Designs

Table 15. Volumetric Properties of Field RAM Mix Designs

Table 16. PGH Results of Field RAM Asphalt Mixtures with Different RAM Types, Sources, and Contents

Table 17. PGH Results of Field RAM Asphalt Mixtures with Different Mix Design Variables

Table 18. PGH Results of Field RAM Asphalt Mixtures with Different Production Variables

Table 19. Virgin and RAM Binder PG Results

Table 20. RBA Results of High-RAM Asphalt Mixtures

Table 21. V-OBC and A-OBC Results of High-RAM Asphalt Mixtures

Table 22. Volumetric Properties of High-RAM Mix Designs at V-OBC and A-OBC

Table 23. Estimated Life Extension Required to Match LCCA NPV of High-RAM Asphalt Mixtures at A-OBC and V-OBC

Table 24. Summary of RBA Sensitivity Evaluation Results