FHWA ALF Update & Performance Testing. Nelson Gibson Spring 2016 ETG Salt Lake City, UT

Transcription

1 FHWA ALF Update & Performance Testing Nelson Gibson Spring 2016 ETG Salt Lake City, UT

2 ALF Cracking Update Water & Delay Outline Non Destructive Evaluation (NDE) to Capture Pavement Fatigue Damage Accumulation Cyclic Fatigue AASHTO TP107 Performance Based Mix Design Proposed Improvement / Change to TP107 Next ALF Experiment

3 ALF Cracking Update Water & Delay Outline Non Destructive Evaluation (NDE) to Capture Pavement Fatigue Damage Accumulation Cyclic Fatigue AASHTO TP107 Performance Based Mix Design Proposed Improvement / Change to TP107 Next ALF Experiment

4

5 ALF Lane # RAP % ABR RAS Virgin PG Grade Drum Discharge Temperature WMA Process Cycles to First ALF Crack Water Foaming Evotherm Water Foaming Evotherm 368,254 Repeating 42,399 88,740 36, ,363 23,005 Repeating 270,058 81,044

6 Underdrain ALF

7 ALF Cracking Update Water & Delay Outline Non Destructive Evaluation (NDE) to Capture Pavement Fatigue Damage Accumulation Cyclic Fatigue AASHTO TP107 Performance Based Mix Design Proposed Improvement / Change to TP107 Next ALF Experiment

8 Modulus Reduction The Field The Laboratory

9

10

11 The Point Is Modulus Reduction Real pavement damage accumulates over multiple events Not a single event The pavement remains intact while it looses a lot of modulus and then a crack occurs Measured by beam or AMPT cyclic fatigue Is it important and key to a comprehensive solution

12 ALF Cracking Update Water & Delay Outline Non Destructive Evaluation (NDE) to Capture Pavement Fatigue Damage Accumulation Cyclic Fatigue AASHTO TP107 Performance Based Mix Design Proposed Improvement / Change to TP107 Next ALF Experiment

13 Performance Based Specifications Predict life. How much life was lost? Gained?

14 Performance Based Specifications Balanced Mix Design Predict life. How much life was lost? Gained? Hit the target. Walk away. Binder Content a number a number

15 Performance Prediction (traffic structure climate) Already has capability Involved. Complicated. Make it simpler

16 Performance Prediction (traffic structure climate) Already has capability Involved. Complicated. Make it simpler Functionality has to be added

17 Performance Criteria National Performance Management Measures MAP-21 Notice of Proposed Rulemaking Rutting Cracking Good Fair Poor 5 mm 10 mm 5% 20 years 13M ESALs

18 1 Virgin Binder 1 RAP Stockpile 3 Virgin Aggregate Stockpiles 3 Design Air Void (3, 4, 5%) 3 Design VMA (13, 14, 15%) 3 Compaction Levels (5, 7, 9%) PG % RAP N Design mm NMAS 21 Mix Designs Combinations Mix-Structure-Traffic

19 Consider these 3 variables as key indicators

20 Consider these 3 variables as key indicators Production

21 Consider these 3 variables as key indicators Installation *G. Huber Production

22 Methodical Volumetric Variation

23 Methodical Volumetric Variation

24 Methodical Volumetric Variation

25 Methodical Volumetric Variation

26 Methodical Volumetric Variation The aggregate Gsb was 2.99 Binder content would be about +0.5% greater if Gsb were near 2.70

27 Methodical Volumetric Variation

28 Structural Analysis Details Structure (ALF) 4-inch asphalt concrete 22-inch crushed aggregate base M R 12,000 psi Subgrade M R 9,000 psi Traffic 13,000,000 ESALs in 20 years Climate National Airport (DCA) MEPDG *.ics weather file

29 Minimum Years Difference in Life (smallest of rutting or cracking) from 20 year Target Design VMA Life Difference b/w As-Design and As- Design A.V Construction In-Place A.V

30 Production Data Example

31 Production Data Example 1 std. deviation VMA / Design A.V / In Place A.V /

32 Production Data Example -0.25% VMA & +0.25% Design A.V

33 ALF Cracking Update Water & Delay Outline Non Destructive Evaluation (NDE) to Capture Pavement Fatigue Damage Accumulation Cyclic Fatigue AASHTO TP107 Performance Based Mix Design Proposed Improvement / Change to TP107 Next ALF Experiment

34 FHWA Instructional Video TP107 pk-v8li-kjqq-z6lmad4v2o_lcr3b

35 FHWA Instructional Video TP107 Part 1.Reheating and Compacting Part 2.Coring and Cutting Part 3.Cleaning and Gluing LVDT Tabs Part 4.Platen Cleaning and Gluing Part 5. Running E* - See also NHI Training Course Part 6.Choosing the Strain Level Part 7.Attaching Specimen and Running Test Part 8.Post Processing alpha-fatigue Part 9.Post Processing LVECD Structural Analysis

36 Guidance on Choosing Strain Levels We went through the trial-and-error so you don t have to (do as much) Based on 64 different mixes tested Identified a failure pattern

37 If the E* is greater than 11,000 MPa, select 300 microstrain as the first specimen's strain If 11,000 > E* > 5,500 Mpa, select 500 microstrain as the first specimen's strain If the E* is less than 5,500 Mpa, select 800 microstrain as the first specimen's strain , , , , ,220 10,969 27,219 64, , , ,464 4,324 12,022 31,468 77, , ,905 8,605 23,704 60, , ,798 8,491 23,721 61, , ,039 3,433 10,350 28,465 71, , ,527 4,929 14,392 38,032 90, ,519 7,766 21,507 53, , ,365 4,422 12,781 32,962 75, , ,634 7,919 21,111 49, , ,630 5,084 13,975 33,872 72, , ,043 3,365 9,518 23,613 51,374 98, ,287 6,646 16,849 37,278 71, ,592 4,742 12,271 27,581 53, ,131 3,450 9,101 20,761 40, ,553 6,859 15,869 31,613 1, ,919 5,246 12,298 24,730 1, ,463 4,064 9,650 19,579 1, ,129 3,187 7,658 15,670 1, ,526 6,140 12,667 1, ,022 4,970 10,332 1, ,633 4,057 8,498 1, ,330 3,339 7,043 1, ,092 2,768 5,879 1, ,310 4,940 1, ,940 4,176 1, ,640 3,550 1, ,393 3,035 1, ,190 2,607 1, ,021 2,250 1, ,950 1, ,697 1, ,483 1, ,301 1, ,145 1, ,011 2,

38 Cycles to Failure Improving Performance Decreasing Performance Fatigue Strain

39 TP Section 11.2 requires three tests need to be completed at three strain levels. 64,000 16,000 Ideally failure cycles should be different by orders of magnitude between 1,000-64,000 *ETG 2012 Meeting Minutes 4,000 1,000

40 To get the right failure result here, how do I figure out what to put in here???

41

42 This is a representation of an infinite number of curves. A mix will land on one curve If you have at least one data point from one trial you can estimate your next strain level with some confidence

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58 If the E* is greater than 11,000 MPa, select 300 microstrain as the first specimen's strain If 11,000 > E* > 5,500 Mpa, select 500 microstrain as the first specimen's strain If the E* is less than 5,500 Mpa, select 800 microstrain as the first specimen's strain , , , , ,220 10,969 27,219 64, , , ,464 4,324 12,022 31,468 77, , ,905 8,605 23,704 60, , ,798 8,491 23,721 61, , ,039 3,433 10,350 28,465 71, , ,527 4,929 14,392 38,032 90, ,519 7,766 21,507 53, , ,365 4,422 12,781 32,962 75, , ,634 7,919 21,111 49, , ,630 5,084 13,975 33,872 72, , ,043 3,365 9,518 23,613 51,374 98, ,287 6,646 16,849 37,278 71, ,592 4,742 12,271 27,581 53, ,131 3,450 9,101 20,761 40, ,553 6,859 15,869 31,613 1, ,919 5,246 12,298 24,730 1, ,463 4,064 9,650 19,579 1, ,129 3,187 7,658 15,670 1, ,526 6,140 12,667 1, ,022 4,970 10,332 1, ,633 4,057 8,498 1, ,330 3,339 7,043 1, ,092 2,768 5,879 1, ,310 4,940 1, ,940 4,176 1, ,640 3,550 1, ,393 3,035 1, ,190 2,607 1, ,021 2,250 1, ,950 1, ,697 1, ,483 1, ,301 1, ,145 1, ,011 2,

59

60

61

62

63

64 ALF Cracking Update Water & Delay Outline Non Destructive Evaluation (NDE) to Capture Pavement Fatigue Damage Accumulation Cyclic Fatigue AASHTO TP107 Performance Based Mix Design Proposed Improvement / Change to TP107 Next ALF Experiment

65 Next ALF Experiment Provide APT performance data (Fatigue & Rutting) for the FHWA Increased Durability from Increased Compaction Initiative 4-inch thick & 1 single lift 19mm NMAS & PG64-22 Rebuild 3 Lanes 91-92% TMD 92-94% TMD 94-96% TMD Contractor can utilize WMA, alternative rollers and pattern, adjust discharge temperate Mix Volumetrics will be the same

66 Historical ALF Project Compaction Requirement Compaction Achieved Whole core Top Lift Bottom lift inch ALF construction 12.5mm NMAS 93.2% +/- 1.1% 92.5% +/ % +/ inch ALF construction 12.5mm NMAS 92% - 94% Set % +/- 1.4% Set % +/- 1.1 Set % +/ inch ALF construction 12.5mm NMAS 92.7% +/ % +/ % +/- 1.4

67 Data from State X

68 Design Air Voids For every 1% increase Design VMA For every 1% increase Compaction Density For every 1% lower in-place Air Voids Fatigue Cracked Area (%) 40% increase in distress 73% decrease in distress 19% decrease in distress Rut Depth (mm) 22% decrease in distress 32% increase in distress 10% decrease in distress * Simplified average of project s comprehensive results - distilled into a single rule-of-thumb

69 Fatigue life Rut life Design Air Voids For every 1% increase Design VMA For every 1% increase Compaction Density For every 1% lower in-place Air Voids 18 year decrease 34 year increase 3 year increase 38 year decrease 6 year increase 17 year decrease * Simplified average of project s comprehensive results - distilled into a single rule-of-thumb These Numbers Could Use Some More Scrutiny.