Characterizing the Effectiveness of Recycling Agents and their Evolution with Aging in Binders and Mixtures with High RAP and/or RAS Contents

Transcription

1 Characterizing the Effectiveness of Recycling Agents and their Evolution with Aging in Binders and Mixtures with High RAP and/or RAS Contents A. Epps Martin, E. Arambula Mercado, F. Kaseer, L. Garcia Cucalon 56 th Idaho Asphalt Conference Moscow, ID October 27, 2016

2 NCHRP 9-58: The Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Amy Epps Martin Fujie Zhou Edith Arambula Mercado Jon Epps Dave Newcomb Charles Glover TTI Elie Hajj Nathan Morian UNR Eun Sug Park Arif Chowdury Jo Daniel UNH Xue Luo Fan Yin Fawaz Kaseer Gayle King Consultant Lorena Garcia Cucalon

3 Motivation High Binder Ratio (RBR) Mitigation Recycling Agent (RA) BENEFITS Economic Environmental Engineering REMAINING ISSUES Engineering Embrittlement Aging Blending Mixture Performance

4 DOT control Mix (0.22 RBR) RAP content: 27% WI DOT & with RA with RA Mix (0.31 RBR) RAP content: 36% Total Agg. 94.4% Virgin Agg. 68.7% Virgin Agg. 60.3% Total Agg. 94.6% RAP Agg. 34.3% RAP Agg. 25.7% Total Binder Virgin binder 4.3% 5.6% RAP binder 1.3% Not to scale Virgin binder +RA 3.7% RAP binder 1.7% Total Binder 5.4%

5 NCHRP 9-58 Research Plan PHASE I Identification of Gaps in Knowledge on RA Use with High RBRs Task 1. Gather Information Task 2. Design Laboratory Experiment Task 3. Document Results in First Interim Report PHASE II Investigation of Effectiveness of RAs in Restoring Binder Rheology, Development of Blending Protocol, and Associated Mixture Performance Task 4. Conduct Laboratory Experiment Task 5. Design Field Experiment and Document Results in Second Interim Report PHASE III Validation of RA Use in Mixtures with High RBRs Task 6. Conduct Field Experiment Task 7. Propose Revisions to AASHTO Specifications and Test Methods Task 8. Develop Training Materials and Best Practices and Deliver Workshop Task 9. Document Results in Final Report

6 Phase II Laboratory Tests BINDER & MORTAR PG - BOTH ΔΔTT cc = (TT SS TT mm ) Glover-Rowe G-R = GG (ccccccδδ) 15 C, rad/sec ssssssδδ Rejuvenating Effectiveness RRRR = (log G R DDDDDD CCCCCCCCCCCCCC log G R RRRRRRRRRRRRRRRR ) log G R DDDDDD CCCCCCCCCCCCCC Carbonyl Area Growth by FT-IR

7 Phase II Laboratory Tests - MIXTURE Stiffness M 25 C E* Cracking Resistance FI by SCB N f by S-VECD RI by UTSST

8 Phase II TX (Expanded) Materials TX: PG RBR (0.1 RAP+0.18 MWAS) + 2.7% Tall Oil T1 (Target=PG 70-22) RBR w/rap only, 0.5 RBR balanced RAP/RAS + Aromatic Extract A1 + NH PG & NV PG 64-28P + TX TOAS

9 RECYCLING AGENT (RA) DOSAGE SELECTION METHOD

10 SELECT MATERIALS PREP MATERIALS CONDUCT LAB TESTS SELECT DOSAGE

11 SELECT MATERIALS Target and base binder PG grade RAP and/or RAS source(s) Recycling Agent (RA) RAP and/or RAS Binder Ratio (RAPBR/ RASBR)

12 PREP MATERIALS Extract and recover binder from RAP and/or RAS source(s) Prepare recycled binder blends: With no RA (control) With low RA dosage With high RA dosage

13 CONDUCT LAB TESTS Obtain high PG grade (PGH) and low PG grade (PGL) per AASHTO M320: Target binder binder blend with no RA (control) binder blend with low RA dosage binder blend with high RA dosage

14 0.3 RBR (PG TxRAP 0.2 TxMWAS T1) Original G*/sin(d) Original RTFO G*/sin(d) G*/sin(d) PAV m-controlled RTFO G*/sin(d) PAV S-controlled 90 0 y = -1.7x High Temp. PG Grade ( C) y = -1.8x y = -1.3x y = -0.7x B (4.5,73) A (4.5,-22) Tc = Low Temp. PG Grade ( C) Target Grade: Dosage (%) Actual Grade: Selected Dosage: 4.5%

15 SELECT DOSAGE Plot original & RTFO PGH, S- & m- controlled PGL vs. RA dosage for all blends Establish linear regression equations Select RA dosage in 0.5% increments to meet target binder PGL using warmer PGL regression line Verify PGH of selected dosage vs. target binder PGH using colder PGH regression line *For RAS mixtures, if dosage >5.5%, replace virgin binder with 50% RA and add other 50%. NO dosage in 0.5% increments to meet PGH & maintain PGL Meets target PGH? YES REPORT w/pg grade

16 High Temp. PG Grade ( C) RBR ( TxRAP 0.25 TxTOAS T1) Original G*/sin(d) Original RTFO G*/sin(d) G*/sin(d) PAV m-controlled RTFO G*/sin(d) PAV S-controlled 0 y = -1.8x y = -2.2x B (10.0,78) -10 y = -2.1x C (11.5,74) y = -1.0x A (10.0,-22) D (11.5,-25) Tc = Tc = Low Temp. PG Grade ( C) Target Grade: Dosage (%) Actual Grade: Selected Dosage: 11.5%

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18 G-R Binder Black Space Diagram log G* 15 C, rad/s 0.3 RBR (0.1 RAP & 0.2 RAS) DOT DOT Control, Control, 64-22, 64-22, NO NO RA RA Blend, 64-22, 4.5% T1 Blend, 64-22, 5.5% A Phase Angle 15 C, rad/s

19 G-R Results w/aging 0.3 RBR (0.1 RAP & 0.2 RAS) RTFO PAV 20 PAV 40 Glover-Rowe Parameter (kpa) % 24% 12% 52% 31% 10% % improvement vs. the DOT control blend 1 DOT Control NO RA Blend % T1 Blend % A1 opt RA < DOT control Blend no RA

20 Binder RE Evolution with PAV Aging 0.3 RBR (0.1 RAP & 0.2 RAS) Blend, 64-22, 4.5% T1 0.4RBR (0.4 RAP) Blend, 64-22, 7.5% T1 80% Blend, 64-22, 5.5% A1 80% Blend, 64-22, 9.5% A1 % Improvement in Log(G-R) 60% 40% 20% 0% Control Blend, 64-22, no RA PAV Aging Time (hours) % Improvement in Log(G-R) 60% 40% 20% 0% Control Blend, 64-22, no RA PAV Aging Time (hours) The rejuvenating effect of RA decreased with PAV aging

21 0.5 RBR (0.25 RAP & 0.25 RAS) % Improvement in Log(G-R) 80% 60% 40% 20% 0% % Improvement in Log(G-R) Blend, 64-22, MWAS, 7.5% T1 Control Blend, 64-22, MWAS, no RA 0 20 PAV Aging Time (hours) RBR (0.25 RAP & 0.25 RAS) Blend, 64-22, TOAS, 11.5% T1 80% 60% 40% 20% Control Blend, 64-22, TOAS, no RA 0% PAV Aging Time (hours) % Improvement in Log(G-R) 80% 60% 40% 20% 0% Binder RE Evolution with PAV Aging 0.5 RBR (0.25 RAP & 0.25 RAS) Blend, 64-28, TOAS, 12.5% T1 Control Blend, 64-28, TOAS, no RA PAV Aging Time (hours)

22 RA Dosage Selection Mixture Validation - M R 1200 LTOA STOA 1000 Resilient Modulus (ksi) DOT control w/ FLD (2.65) w/ (3.5%) w/ OPT (4.5%) w/ OPT (5.5%)

23 RA Dosage Selection Mixture Validation - SCB 8.0 STOA LTOA 6.0 Flexibility Index (FI) DOT Control w/ FLD (2.65%) w/ 3.5% w/ OPT (4.5%) w/ OPT (5.5%)

24 Phase IIB Materials TX: PG RBR (0.1 RAP+0.18 MWAS) + 2.7% Tall Oil T1 (Target=PG 70-22) + Better Base Binder (less negative T c ) + Softer Base Binder + Vegetable Oil V1, + Bio-Based Oil B RBR balanced RAP/RAS w/ TX TOAS Related Phase IIA results

25 Phase IIB RA Dosage Selection beyond restoring PGL/checking PGH by restoring T c to -5, restoring PGH + HWTT to preclude over-softening + BBR Sliver (AASHTO TP 125) for mixture Black Space + DSC (& UTSST) for onset of brittle behavior

26 SELECT DOSAGE Plot original & RTFO PGH, S- & m- controlled PGL vs. RA dosage for all blends Establish linear regression equations Select RA dosage in 0.5% increments to meet target binder PGL using warmer PGL regression line Verify PGH of selected dosage vs. target binder PGH using colder PGH regression line *For RAS mixtures, if dosage >5.5%, replace virgin binder with 50% RA and add other 50%. NO dosage in 0.5% increments to meet PGH & maintain PGL Meets YES target PGH? dosage in 0.5% increments to reduce T c to -5 & REPORT w/pg grade

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28 G-R 21 C (0.28 RBR) Blends w/ IN PG Restore PGL/Check PGH and Restore T c log G* (Pa) DOT Control IN NO RA Blend IN % V Blend IN % T1 Blend IN % B Blend IN % A Phase Angle (degrees) Glover-Rowe Parameter (kpa) DOT Control IN NO RA RTFO PAV 20 PAV 40 Blend IN % T1 Blend IN % A1 Blend IN % V1 Blend IN % B T= 21 C, same thresholds RAs may not be needed with 0.3 RBR and a better binder

29 log G* (Pa) G-R 21 C (0.28 RBR) Blends w/ TX PG Restore PGL/Check PGH DOT Control NO RA Blend 4% V Blend 4.5% T1 Blend 4% B Blend 5.5% A Phase Angle (degrees) Glover-Rowe Parameter (kpa) DOT Control NO RA RTFO PAV 20 PAV 40 NA Blend 4.5% T1 NA Blend 5.5% A1 Blend 4% V1 Blend 4% B T= 21 C, same thresholds Control blend ages beyond the thresholds RAs improve the blends

30 G-R 21 C (0.28 RBR) Blends w/ TX PG Restore T c log G* (Pa) DOT Control NO RA Blend 8.5% V1 Blend 12.5% T1 Blend 7% B Blend 9.5% A1 HWTT Rutting!!! Glover-Rowe Parameter (kpa) DOT Control NO RA RTFO PAV 20 PAV 40 Blend 12.5% T1 Blend 9.5% A1 Blend 8.5% V1 Blend 7% B Phase Angle (degrees)

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32 SELECT DOSAGE Plot original & RTFO PGH, S- & m- controlled PGL vs. RA dosage for all blends Establish linear regression equations *For RAS mixtures, if dosage >5.5%, replace virgin binder with 50% RA and add other 50%. Select RA dosage in 0.5% increments to restore PGH to minimum that meets target using colder PGH regression line REPORT w/ PG grade & T c

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34 log G* (Pa) DOT Control NO RA Blend 5.5% V1 Estimated 21 C (0.28 RBR) Blends w/ TX PG Restore PGH Blend 6% T1 Blend 6.5% B Blend 6.5% A Phase Angle (degrees) Glover-Rowe Parameter (kpa) DOT Control NO RA RTFO PAV 20 PAV 40 Blend 6% T1 Blend 6.5% A1 Blend 5.5% V1 Blend 6.5% B

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36 Cumulative G-R Virgin (64-22) DOT Control NO RA 4.5% T1 4.5% A1 4.5% V1 4.5% B log Com. G-R PAV aging (hours )

37 Finalize RA Dosage Selection Method Consider Incompatibility by Chemical or Rheological Properties Complete Aging Analysis to explore oven vs PAV aging, chemical vs rheological properties Characterize Mixtures Next Steps Cracking Resistance FI by SCB, N f by S-VECD, RI by UTSST Embrittlement - UTSST Viscous-Glassy Transition, Mixture Black Space with BBR Sliver and E*, φ Evaluate Phase III Field Projects to set thresholds for Rejuvenating Effectiveness w/aging

38 Phase III Field Projects WI 9/16: 0.3 RBR RA: V2 IN 9/15: 0.4, 0.5 RBR RA: T2?? DE 2016: PG RA:?? NV 9/15: 0.3 RAPBR RAs: T2 + A2 TX 6/14: 0.3 RBR RA: T1

39 Dosage Selection NV Field Project RE & Evolution HWTT M R & SCB (STOA & LTOA) E* & UTSST (LTOA) S-VECD (LTOA) Target 64-28P (R) 64-28P (0.3 RAPBR) (R) +T2@FLD (2%) (R) +A2@FLD (2%) DOT Control 64-28P (0.15 RAPBR) Laboratory Mixtures (LMLC) & Field Mixtures (RPMLC, Cores) Binder Mod Binder RA Type Mixture

40 Dosage Selection IN Field Project Laboratory Mixtures (LMLC) & Field Mixtures (RPMLC, Cores) RE & Evolution HWTT M R & SCB (STOA & LTOA) E* & UTSST (LTOA) S-VECD (LTOA) Target DOT Control (58-28) (0.32 RBR) (0.25 RAP & 0.07 MWAS) (58-28) (0.42 RBR) (0.14 RAP & 0.28 MWAS) + T2 FLD (3%) Binder Mixture High RAS

41 WI Field Project Laboratory Mixtures (LMLC) & Field Mixtures (RPMLC, Cores) DOT Control 58-28S (0.22 RAPBR) 58-28S (0.3 RAPBR) 52-34S (0.3 RAPBR) 58-28S (0.3 RAPBR) + V2@FLD Dosage Selection Binder RE & Evolution HWTT M R & SCB (STOA & LTOA) E* & UTSST (LTOA) Mod Binders Mixture V Type

42 Contact Contact Amy Epps Martin, Ph.D., P.E. Professor and A.P. & Florence Wiley Faculty Fellow Zachry Department of Civil Engineering Research Engineer (TTI) 310D CE/TTI 3136 TAMU College Station, TX (979)