Comparative Evaluation of MSCR Tests on Warm-Mix Technologies

Transcription

1 Comparative Evaluation of MSCR Tests on Warm-Mix Technologies Zelelew H., Paugh C., Corrigan M., and Belagutti S. FHWA Office of Pavement, Construction, and Asset Management 1200 New Jersey Ave. SE Washington DC nd International Warm-mix Conference St. Louis Missouri October 11-13, 2011

2 Outline Project Descriptions Binder Testing Performance Testing Relating MSCR to Performance Summary of Findings

3 Project Descriptions Location: Pleasant Gap, PA Duration: May to June 2009 Five Plant Produced 9.5mm NMAS Asphalt Mixtures o HMA (Control Mix) o WMA (Advera ) o WMA (LEA) o WMA (Gencor) o WMA (Sasobit ) Surface Layers Foaming Process Wax Additive PG Mixture Production: Counter-flow Drum Mix Plant

4 Binder Testing Binder ID Source Dosage Rates (%) Remark PG Advera Lab Prepared (LP) 0.25 by weight (Total Mix) Sasobit Plant Supplied (PS) 1.50 LEA Lab Prepared (LP) 0.20 by weight (Binder) Gencor Plant Supplied (PS) 1.25 Lab Mixing o Silverson High Shear Mixer

5 PG Verification AASHTO M Binder ID M320 Continuous PG High Temp. Effects PG Low Temp. PG PG Advera PG Slightly Increased No Change Sasobit PG Increased by +6 C Slightly Decreased LEA PG Slightly Decreased Slightly Decreased Gencor PG Slightly Increased Decreased by -3.4 C

6 MSCR (TP 70-11) Determines the Presence of Elastic Response using DSR Temperature Selection o LTPPBind V3.1 o 52-70C Duration (10 Cycles) o 1 sec (Creep) o 9 sec (Recovery) Stress Mode o to 2.56 kpa o 0.1 & 3.2 kpa Strain (%) Example: kpa 10

7 MSCR Test Parameters Using 0.1 & 3.2 kpa Stress Levels o Non-recoverable Creep Compliance (J nr ) o Percent Difference in Jnr (J nrdiff ) o Percent Recovery (R) o Difference in R (R diff ) J nrdiff = J nr (3.2) J nr (0.1) x 100 J nr (0.1) R diff = R(0.1) R (3.2) x 100 R (0.1)

8 Computations

9 ..

10 ..

11 Stress Sensitivity 1.00 (52 C) 0.80 J nr (1/kPa) PG Advera Sasobit LEA Gencor Shear Stress (kpa)

12 (58 C) 2.25 J nr (1/kPa) 1.50 PG Advera Sasobit LEA Gencor Shear Stress (kpa)

13 (64 C) 4.50 J nr (1/kPa) 3.00 PG Advera Sasobit LEA Gencor Shear Stress (kpa)

14 (70 C) 9.00 J nr (1/kPa) 6.00 PG Advera Sasobit LEA Gencor Shear Stress (kpa)

15 Summary C J nr (1/kPa) C C 52 C Shear Stress (kpa)

16 J nr vs. Temperature PG Advera Sasobit LEA Gencor (0.1 kpa) J nr (1/kPa) Temperature (C)

17 PG Advera Sasobit LEA Gencor (3.2 kpa) J nr (1/kPa) Temperature (C)

18 J nrdiff vs. Temperature

19 PG Classification AASHTO MP 19 Table 3 (MSCR) Traffic Loading Jnr (3.2 kpa) (1/kPa) Jnrdiff (%) Standard Grade (S) < 4.0 Heavy Grade (H) < 2.0 Very Heavy Grade (V) < 1.0 Maximum 75 % Extremely Heavy Grade (E) < 0.5

20 ... Temperature ( C) Binder ID Jnrdiff (%) Jnr (3.2 kpa) (1/kPa) PG Grade (Table 3) PG PG H Advera PG H 58 Sasobit PG V LEA PG H Gencor PG H

21 Binder Master Curve Temperature ( C): 4.4, 21.1, 37.8, and 54.4 Frequency (Hz): to 25 (0.1 to rad/s) Master Curve Generalized Logistic Function Pellinen, Witczak, and Bonaquist (2004)

22 ... 1.E+10 PG Shear Modulus, G* (kpa) 1.E+08 1.E+06 1.E+04 1.E+02 Advera Sasobit LEA Gencor 1.E+00 1.E-06 1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06 1.E+08 Reduced Frequency (Hz) (T Ref = 21.1C)

23 Mixture Design Parameter Control HMA WMA Advera Sasobit LEA Gencor Sieve No. (mm) Percent Passing (%) 1/2 in (12.5 mm) /8 in (9.5 mm) 98.0 No. 4 (4.75 mm) 72.0 No. 8 (2.36 mm) 46.0 No. 16 (1.18 mm) 26.0 No. 30 (600 μm) 17.0 No. 50 (300 μm) 11.0 No. 100 (150 μm) 8.0 No. 200 (75 μm) 5.0 CAA (%) 100/100 FAA (%) 45.2 F & E (%) 0.2 SE (%) 78.0

24 .. Parameters Control HMA WMA Advera Sasobit LEA Gencor P b (%) 5.9 V a (%) 4.0 VMA (%) 16.3 VFA (%) 76.0 F/P be 0.90 P b = percent binder content, V a = percent air voids, VMA= percent voids in mineral aggregates, VFA= percent voids filled with asphalt, F/P be = fine dust to effective binder ratio. o < 3 x10 6 ESAL o N Design = 75

25 Prod & In-Place Temp Mixture ID Temperature ( C) Production Difference 1 In-place Difference 2 Control HMA Advera Sasobit LEA Gencor reduction in production temperature 2 reduction in in-place temperature

26 On-site Paving

27 Performance Test -TP 79 Asphalt Mixture Performance Tester (AMPT) Measures the Engineering Properties of Asphalt Mixtures o Dynamic Modulus ( E* ): Stiffness o Flow Number (Fn): Rutting under Cyclic Load AMPT (IPC Global)

28 Dynamic Modulus Test Temperature ( C) 4.4, 21.1, 37.8, and 54.4 Frequency (Hz): 25, 10, 5, 1, 0.5, and Replicates Unconfined Mode μstrain

29 Master Curve Control HMA Advera Sasobit Dynamic Modulus, E* (MPa) LEA Gencor 10 1.E-06 1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06 1.E+08 Reduced Frequency (Hz) (T Ref = 21.1C)

30 Flow Number Test Temperature ( C) 45.8, 51.8, and Replicates Confined Test 690/69 kpa Load (0.1 sec) and Unload (0.9 sec) Termination Criterion 10,000 Cycles or 50,000 Microstrain

31 Selection of Test Temperature Weather Station State College, PA Adjustments 50% Reliability 20 mm Depth PG Temp = 51.8 C LTPPBind V3.1

32 .. Accumulated Strain Primary Secondary Tertiary Intercept Slope Flow Number (Fn) Number of Cycles

33 Fn C 51.8 C 57.8 C Flow Number (Cycles) Control HMA Advera Sasobit LEA Gencor

34 Slope C 51.8 C 57.8 C Slope (Microns/Cycles) Control HMA Advera Sasobit LEA Gencor

35 Intercept C 51.8 C 57.8 C Intercept (Microns) Control HMA Advera Sasobit LEA Gencor

36 Variations in Performance Binder Rheological Properties Dosage Rates Intrinsic Properties of WMA Technologies Production Temperature Control HMA Advera C 51.8 C 57.8 C Sasobit LEA Dynamic Modulus, E* (MPa) Gencor Flow Number (Cycles) E-06 1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06 1.E+08 Reduced Frequency (Hz) (T Ref = 21.1C) 0 Control HMA Advera Sasobit LEA Gencor

37 Typical Trends E* Sin( ) Fn Jnr Jnr Intercept Slope Jnr Jnr

38 Relating Jnr to E* /sin( ) 700 E* /sin ( ) (MPa), 5 Hz and 54.4 C Sasobit Gencor Advera LEA HMA Jnr at 3.2 kpa (1/kP)

39 Relating Jnr to Fn LEA 8000 Flow Number (Cycles) Sasobit HMA 2000 Advera Gencor Jnr at 3.2 kpa (1/kP)

40 Relating Jnr to Slope 20 Gencor 16 Slope (Microns/Cycle) 12 8 Advera HMA Sasobit 4 LEA Jnr at 3.2 kpa (1/kP)

41 Relating Jnr to Intercept Gencor HMA Intercept (Microns) Sasobit Advera LEA Jnr at 3.2 kpa (1/kP)

42 Summary of Findings Binder Test ( G* and MSCR) Performance Test ( E* and Fn) MSCR Test: Temperature-Stress Dependent Test Sasobit Produced the Lowest Creep Compliance Values at all Test Temperatures and Shear Stress Levels Relating Jnr to AMPT E* and Fn Test Parameters

43 Acknowledgment o PennDOT o Tom Abbey and the Staff at Glenn O. Hawbaker Inc. o RamakrishnaReddy (MATL PE) o MATL/ABTL Techs

44 Thank You Questions