Binder and Mixture ETG Update

Transcription

1 Binder and Mixture ETG Update 1

2 2

3 High Temperature Binder Criteria Study Refine the Multi-Stress Creep and Recovery Test Evaluate multiple binders Evaluate binder and mix properties to develop specification criteria. 3

4 NCHRP Rutting Test Repeated Creep Recovery Test Shear Stress, 68 1 Shear Stain, mm/mm Accumulated Strain

5 MINN Road 58-XX binders Depending on base AC and stress level there is reversal of performance Jnr C C C C C C C C C stress pa 5

6 Hamburg Rut testing MINN Road mixes Jnr 1kPa y = x R 2 = Jnr Rutting mm

7 Hamburg Rut testing MINN Road mixes Jnr y = x R 2 = Jnr rut mm 7

8 As-Built Pavement Lanes R-AZ PG Air Blown 0-22Control SBS LG CR-TB TP PG PG SBS Air Blown Fibers SBS LG TP

9 HMA Layer Rutting for All Lanes L9S1(SBS ") L9S2(SBS ") L6S1(Terpolymer 4") L8S1(Control 6") HMA Layer Rutting, in L10S1(Air Blown 6") L11S1(SBS-lg 6") L3S1(Air Blown 4") L2S1(Control 4") L1S1(CR AZ 4") L4S1(SBS-lg 4") L12S1(Terpolymer 6") 0.0 L7S1(Fibers 4") 0 10,000 20,000 30,000 40,000 50,000 L5S1(TBCR 60,000 4") ALF Wheel Passes 9

10 Jnr ALF binder 64C C AB 64C SBS LG control 64C Elvaloy 64C TBCR 64C 0.15 Jnr Stress Pa 10

11 y = x R 2 = G*/sin d 64C rutting inches 11

12 y = x R 2 = Jnr ALF Rutting in 12

13 Ongoing work Define Jnr based on neat binders. Evaluate SPT creep and recovery testing to relate stress level in binder to mix. Evaluate test sections with know performance. 13

14 Evaluation of the Repeated Creep and Recovery Test Method as an Alternative SHRP + Requirement 14

15 No ER So What Do We Do? Use Use DSR DSR Approach Muti Stress Creep Recovery Test Two creep stress levels Ten cycles per stress level For Elastomeric modifiers Specify: % strain recovery > 15% or 20% Overall change between stress levels Run on the RTFOT Run on the same sample as RTFOT grading 15

16 Proposed MSCR TEST Protocol 3200 Pa Creep Stress 100 Pa 1 10 time Creep Strain time 16

17 What criteria? % recovered strain Creep 1st cycle 70C 1000 Pa (Peak Strain - recovered Strain)/Peak Strain % strain control Elvaloy Stylink AB time 17

18 Two s s with SBS. Not all binders are the same. 90 Differential 30 40% reduction Differential 18 81% reduction % recovery kPa kPa kPa kPa SBS SBS 18

19 MSCR selection of stress levels poor structure good structure Jnr Pa Stress Pa 19

20 Comparison of MSCR-3200 Recovery and Elastic Recovery MSCR Pa y = 0.83x R 2 = 0.21 Recovery, % Elastic Recovery 20

21 Multi-Lab Reproducibility: 100 Pa Recovery Pa Grade AI MTE FHWA Ave StDev CV PG % PG % PG % PG % PG % PG % PG % PG % PG % 21

22 Multi-Lab Reproducibility: 3200 Pa Recovery Pa Grade AI MTE FHWA Ave StDev CV PG PG % PG % PG % PG % PG % PG % PG % PG % 22

23 Effect of RTFO Aging Lab Aged Recovery Pa Grade AI MTE FHWA Ave StDev CV PG % PG % Recovery Pa Grade AI MTE FHWA Ave StDev CV PG % PG % MTE RTFO- Aged Recovery Pa Grade AI MTE FHWA Ave StDev CV PG % PG % Recovery Pa Grade AI MTE FHWA Ave StDev CV PG % PG % 23

24 Effect of RTFO Aging Lab Aged Recovery Pa Grade AI MTE FHWA Ave StDev CV PG % PG % Recovery Pa Grade AI MTE FHWA Ave StDev CV PG % PG % MTE RTFO- Aged Recovery Pa Grade AI MTE FHWA Ave StDev CV PG % PG % Recovery Pa Grade AI MTE FHWA Ave StDev CV PG % PG % 24

25 Phosphoric Acid Modified Asphalt FHWA Study 25

26 Four SHRP Asphalts AAD-1 AAK-1 AAM-1 ABM-1 Origin Grade Asphaltene % Polar Aromatics Napthenic Aromatics Saturates CA Coastal PG Boscan PG West TX Int. PG CA Valley PG

27 PAV Aging 100 o C, AAM-1 Under Air 1% Phosphoric Acid Stiffness G*/Sinδ/kPa Control 105% 115% P2O Hours 27

28 PAV Aging 100 o C, ABM-1 Under Air 1% Phosphoric Acid Stiffness G*/Sinδ/kPa Control 105% 115% P2O Hours 28

29 Effect of 115% PPA Acid Modification on Original PG Grade Degrres Centigrade AAD-1 AAK-1 AAM-1 ABM-1 60% Bach 94% Bach Whiting Holly % Acid 29

30 Conclusion Based on 24 Hour Stiffness Any of the Phosphoric Acid Grades can be used Acids Containing Water Cause Foaming Green Acid is Likely to Cause Corrosion Stiffness is Asphalt Dependant AAK-1 1 (Boscan) is the Most Responsive ABM-1 1 (CA Valley) Showed No Stiffness Increase 30

31 Effect of Water on Gyratory Cores - ALF Mix no lime 31

32 Conclusion Effect of Water on Gyratory Cores PPA does not seem to be leaching out. 32

33 Proposed Work Plan Three binders with different sensitivities to PPA Two aggregates, non stripping and stripping; Amine anti- strip additives and lime Four stripping tests Effect of Polymer Modification with SBS 33

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35 Superpave Gyratory Compactor Calibration Making Superpave Mixtures Consistent 35

36 4.1 AASHTO Designation: T Preparing... Specimens by SGC Superpave Gyratory Compactor an average internal angle of (only internal angle with simulated mix measurement) 36

37 Specification Recommendations Drop procedures related to use of HMA drop reference in T312; eliminate TP48 Implement new TP for simulated loading add reference in T312 Precision: Troxler 4140 NOT INCLUDED Refer to manufacturers recommendations Applies to specific procedures for using various devices Applies to hot-versus versus-cold question(s). Inform users that RAM DAV2/HMS Angle tolerance: move to +/ deg 37

38 Internal Angle of Gyration Mixless Mixless measuring devices AASHTO AASHTO provisional procedures for mix simulation SGC SGC guidance/rationale document 38

39 TP-62 Determination of Dynamic Modulus 9-29: Superpave Performance Tester for dynamic modulus TP 62 Dynamic Modulus E* Accommodate Superpave Performance Tester Separate Std for sample preparation Separate Std. for master curve 39

40 Fine Aggregate Specific Gravity Issues Task Group Objectives: Identify problems/issues with current standard AASHTO T 84 Evaluate alternate methods Make recommendations regarding changes and/or new methods Additional scope -- Mixture gravity determination issues T

41 9-33: A Mix Design Manual for Hot Mix Asphalt Final draft end of 2006 will modify build upon Superpave method to Asphalt Institute Manual SP-02: New volumetric criteria. N-design Simple performance test(s). Criteria developed with M-E M E design guide performance models and software. Framework for integrated mix and structural design. Advanced Asphalt Technologies (August 2006) 41

42 Other NCHRP Projects 34: : Improved Conditioning Procedure for Moisture Susceptibility : Endurance Limit of HMA Mixtures to Prevent Fatigue Cracking 9-39: Determining Mixing and Compaction Temperatures of PG Binders in HMA : : Development of Specification Criteria for Mineral Fines Used in HMA 42

43 AASHTO M 323 Design Guidance Combined New and RAP Aggregates Gradation Angularity Flat and Elongated Other Tests?? Binder Grade Changes?? < 15 % RAP, no grade change % RAP, use one grade softer > 25 % RAP, use blending chart 43

44 Thank You pavements 44