NCHRP 9-58 The Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Project Update

Transcription

1 NCHRP 9-58 The Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Project Update Asphalt Mixture & Construction Expert Task Group September 20, 2017

2 Research Team Amy Epps Martin Edith Arambula-Mercado Jon Epps Dave Newcomb Charles Glover Arif Chowdury Fan Yin Fawaz Kaseer Lorena Garcia Cucalon Akash Bajaj TTI Elie Hajj Nathan Morian Sara Pournoman Jo Daniel Reyhaneh Rahbar-Rastegar Gayle King UNR UNH Consultant

3 Outline NCHRP 9-58 Objectives & Research Plan Revised Phase II Field Projects, Materials, & Laboratory Tests Practical Evaluation Tools for High RBR Binder Blends & Mixtures Engineering Binder Blends Moving Forward Phase III Work Plan

4 NCHRP 9-58 Objectives High RBR = Assess effectiveness of RAs to partially restore binder rheology improve mixture cracking performance at optimum dosage rates Evaluate the evolution of RA effectiveness with aging Recommend evaluation tools

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 Bozeman, MT September 20, 2017

6 Field Projects WI 9/16 0.2, 0.3 RAPBR RA: V2 IN 9/15 0.3, 0.4 RBR RA: T2 NV 9/ , 0.3 RAPBR RAs: T2 + A2 TX 6/ RBR RA: T1 DE 12/16 0.3, 0.4 RBR RA: T2

7 Revised Phase II Materials Combinations RAP TX NH NV IN Base Binder Recycling Agents ( T c ) TX PG (-4.6), PG 70-22P (-4.9) NH PG (+1.4) NV PG 64-28P (-3.6) IN PG (-1.2), PG (-8) MN PG (0) RAS TX MWAS, TOAS CA TOAS IN MWAS Recycling Agents Virgin Aggregates T1, T2 A1, A2 V1, V2 B TX NV IN Rejuvenated Mixture Rejuvenated Blend

8 Revised Phase II Lab Tests BINDER & MORTAR BOTH: PGH, PGL ΔT c = (T S T m ) Glover-Rowe G-R = G (cccδ) 15 C, rad/sec sssδ T 10 rad/sec Carbonyl Area Growth by FT-IR T g End & T g Inflection by DSC SAR-AD

9 Revised Phase II Lab Tests - MIXTURE Stiffness M 25 C E*, φ + Mixture G-R Cracking Resistance FI, CRI by I-FIT (SCB) DCC by S-VECD CRI by UTSST S, m-value by BBR Sliver Rutting Resistance RD by HWTT, APA Jr

10 Practical Evaluation Tools RA Dosage Selection (w/aging) Restore PGL (and Verify PGH) Achieve ΔT c = -5.0 Restore Continuous PGH Balanced Binder Blends Estimate PGH & RA Dosage Mixture Validation

11 RA Dosage Selection 7.0 DOT Control (0.28 RBR) TX NO RA Recycled (0.28 RBR) TX % A Recycled (0.28 RBR) TX % B BLOCK CRACKING ZONE Recycled (0.28 RBR) TX % T Recycled (0.28 RBR) TX % V 7.0 DOT Control (0.28 RBR) TX NO RA Recycled (0.28 RBR) TX % A Recycled (0.28 RBR) TX % B BLOCK CRACKING ZONE Recycled (0.28 RBR) TX % T Recycled (0.28 RBR) TX % V 7.0 DOT Control (0.28 RBR) TX NO RA Recycled (0.28 RBR) TX % A Recycled (0.28 RBR) TX % B BLOCK CRACKING ZONE Recycled (0.28 RBR) TX % T Recycled (0.28 RBR) TX % V log G* (Pa) hr PAV 20-hr PAV RTFO NO BLOCK CRACKING ZONE Phase Angle (degrees) log G* (Pa) hr PAV 20-hr PAV Rutting 4.0 RTFO NO BLOCK CRACKING ZONE Phase Angle (degrees) log G* (Pa) hr PAV 20-hr PAV No rut w/softer IN RTFO NO BLOCK CRACKING ZONE Phase Angle (degrees) 1) Dosage to restore PG (Restore PGL - verify PGH) 2) Dosage to reduce ΔT c to ) Dosage to restore PGH to target PGH Dosage too low Dosage too high Adequate Dosage

12 RA Dosage Selection: Restore continuous PGH Rutting 0.5 RBR 0.25 RAP 0.25 TOAS

13 RA Dosage Selection: Restore continuous PGH No rutting BALANCED 0.5 RBR 0.4 RAP 0.1 TOAS Phase III

14 Balanced Binder Blends - Blending Chart NH Virgin Binder (⁰C) RBR (0.4 TXRAP) + NH RBR RAP Binder PG (⁰C) PGH (OB) PGL PGH (0.4 RBR Blend) PGL (0.4 RBR Blend) PPP BBBBB = RRRRR PPP RRR + (VVV PPP V.bbbbbb )

15 Balanced Binder Blends - Estimate PGH Measured PGH RBR (RAP+MWAS) RBR (only RAP) 0.4 RBR (only RAP) RBR (RAP+MWAS) 0.5 RBR (RAP+TOAS) RBR (only RAP) 64 LOE Calculated PGH PPP BBBBB = RRRRR PPP RRR + (RRSBB PPP RRS ) + (VVV PPP V.bbbbbb ) All recycled binder blends without RA

16 Estimate RA dosage to restore continuous PGH 112 T1, T2, A1, A2, V1, B 112 T1, T2, A1, A2, V1, B PGH (Control Blend) y = 1.663x R² = RBR (RAP+MWAS) 0.3 RBR (only RAP) 0.4 RBR (only RAP) 0.5 RBR (RAP+MWAS) 0.5 RBR (RAP+TOAS) 0.7 RBR (only RAP) RA Dosage (%) PGH (Control Blend) y = x R² = RBR (RAP+MWAS) 0.3 RBR (only RAP) 0.4 RBR (only RAP) 0.5 RBR (RAP+MWAS) 0.5 RBR (RAP+TOAS) 0.7 RBR (only RAP) RA Dosage (%) Dosage to restore PGH to 70 Dosage to restore PGH to 64 %RR = (PPP BBBBB PPP TTTTTT ) /1.7 Phase III

17 control field PGL PGH TX Mixture Validation control field PGL PGH

18 control PGL PGH IN Mixture Validation control PGL PGH Phase III

19 Engineering Binder Blends Chemical Compatibility Representative Binder Blending Binder Blend Aging Prediction Rheological Balance

20 RHEOLOGICAL BALANCE Highlights Tools/Partner Rejuvenation Aging Restore PG, reduce G-R, reduce T δ=45 Increase in G-R and T δ=45, with some at faster rate than control blends RA can experience chemical changes with aging that affect rheology DSR/TTI DSR & FT-IR/TTI DSR & FT-IR/TTI Phase III

21 Rheological Balance: Crossover Temperature (T δ=45 ) Dynamic Shear Modulus (kpa) 1.E E Determination by T Sweep G* G' G" 1.E T T g g 1.E Rejuvenated Recycled Base Binder Blend T δ=45 T δ=45 TX PG PG E Temperature ( C) 0.5 RBR 7.5% RA 1.E Glover-Rowe, 0.005rad/s, 15 C (kpa) 1.E E E E E E E Preliminary Thresholds y = 0.001x R² = C - Warning 45 C - Limit Binders and Blends WMA 600kPa 180kPa Rejuvenated Blends Polymer Modified Crossover Temperature, 10rad/s ( C) Note: Τ δ=45 in this study was obtained from mastercurves and time-temperature superposition.

22 Rheological Balance: Crossover Temperature (T δ=45 ) Base Binders and DOT Control Blends Crossover Temperature, 10rad/s ( C) C Original RTFO PAV 20 PAV C 45 C 32 C C C TX PG NH PG IN PG TX PG TX RAP 0.18 MWAS C NH PG TX RAP 0.18 MWAS C IN PG TX RAP 0.18 MWAS Important to select high quality base binder with better T c and T δ=45 Binders of same PG can have different T δ=45 Challenging TX materials combo

23 Rheological Balance and Long-Term Aging High RBR Rejuvenated Blends Temperature ( C) PGH C 32 C RTFO PAV 20 PAV 40 PGH C NH PG NH PG NH RAP 0.1 CA TOAS 9% T1 C NH PG NH RAP 0.1 CA TOAS 9% V2 NH PG TX RAP 0.1TX TOAS 14% T1 NH PG TX RAP 0.1TX TOAS 14% V2 Tc Balanced rutting C cracking resistance. Balanced RAP and RAS It is possible to recycle and rejuvenate high RBR blends. NH PG NH RAP +8%B 10/14

24 Mixture Cracking Resistance Moving Forward Phase III Binder Availability RA Type Selection Climate Effects

25 Mixture Cracking Resistance BBR Sliver Phase III for WI & DE

26 Binder Availability: TX & NH RAP with RA RAP RAP+RA (added to the binder) RAP+RA (added to the RAP) 100% 86.9% Binder Availability 80% 60% 40% higher Marginal Stiffer RAP availability increase yielded when lower RA binder is added to to availability the the binder RAP 43.7% 40.8% 53.0% 73.4% 75.6% 20% 0.3 RBR 0% TX RAP TX & NH RAP binder contents = 4.7%, 4.0% respectively Mixture Total binder content: 4.5% NH RAP PGH PGH Phase III for IN, NV, WI, & DE + Unheated

27 RA Type Selection Chemistry FT-IR Rheology - DSR 60 RTFO PAV 20 PAV 40 1.E Original RTFO PAV 20 PAV 40 Σ Area (a.u.) η* at 15ᵒC and 10 rad/s (Pa.s) 1.E E E E E T1 T2 A1 V2 V1 B 1.E+00 RA with smallest FT-IR registered minimal in rheology T1 w/ greatest in rheology & among highest FT-IR T1 A1 V2 B Phase III w/ 0.5 RBR blends w/wi matls + G-R & T δ=45 w/aging + FI

28 Climate Effects 9-58 Cumulative Degree Days (CDD) 9-52 Ratio vs CDD 9-52: STOA 135C + LTOA 85C = 16,000 CDD = 11 mos warmer, 22 mos colder climates Phase III w/m R, Cracking Resistance + Limited Extracted Binders w/g-r

29 UTILIZE WI & DE Materials PROPOSE VERIFY Practical Tools RBR, RA Dosage Limits Binder & Mix Thresholds Phase III Work Plan PROVIDE Materials Selection Guidance EVALUATE Lab vs Field Aging REVISE AASHTO Standards

30 NCHRP 9-58 Products High RBR = Material Selection Guidelines RA Dosage Selection Method Evaluation Tools w/aging protocols, RA blending methods, binder blend & mixture tests & thresholds AASHTO recommended practice Better Understanding of Recycled Binder Availability (Degree of Blending) Chemical Compatibility Future Research

31 THANK YOU! Amy Epps Martin (979) Edith Arámbula Mercado (979)