Perpetual Asphalt Pavements: Materials, Analysis/Design, Construction, and Other Considerations

Transcription

1 Perpetual Asphalt Pavements: Materials, Analysis/Design, Construction, and Other Considerations Carl L. Monismith Pavement Research Center University of California, Berkeley 2006 International Conference on Perpetual Pavement Columbus, Ohio September 13-15, 15, 2006

2 Background Presentation Overview contributions to current approach to long-life life (perpetual pavement) design Example design and construction (I-710 full depth section) Conference sessions Categories of papers Additional considerations/challenges

3 Lest We Forget Early examples of Perpetual Pavements Appian Way (Via Appia), Roman construction, Italy; circa 300 B.C. Warrenite Bitulithic Pavements, U.S; circa 1910 onward to 1920 s Emphasis on good good construction

4 Perpetual Pavement Appian Way (Via Appia) (Courtesy Prof. J.P. Mahoney)

5 Warrenite Pavement Plaque (Courtesy James Martin)

6 The Modern Era (Since the 1950 s) Some key events contributing to current developments AASHO Road Test, Ottawa, IL: NRC-HRB, International Conference on Asphalt Pavements, University of Michigan, 1962

7 National Research Council/ Highway Research Board AASHO Road Test Highway Research Board Fred Burggraf; ; Director W.N. Carey, Road Test Chief Engineer National Advisory Committee K.B. Woods, Purdue Univ.: Chairman W.A. Bugge,, Director, Wash. Hwy Dept.: Co-Chairman Chairman

8 Fred Burggraf

9 W. N. Carey, Jr.

10 K.B. Woods

11 HRB Special Report 73

12 International Conference on the Structural Design of Asphalt Pavements; August,1962 University of Michigan, Ann Arbor Key individuals The Asphalt Institute: J.E Buchanan, F. N. Finn The University of Michigan: W. S. Housel, W. K. Parr

13 J. E. Buchanan, President, TAI

14 F. N. Finn, Chaiman,, TAI Board of Study

15 W. S. Housel, Prof. of Civil Engin.

16 W. K. Parr Assoc. Prof. of Civil Engin.. & Secretay- Treasurer, AAPT

17 Mechanistic-Empirical Design: Key Impetus Multi-Layer Elastic Analysis Materials Characterization Stiffness Distress Characteristics Design Framework

18 Multilayer Elastic Analysis Programs BISTRO, BISAR (Shell) ELSYM (based on Chevron program; UC Berkeley, FHWA) PDMAP (PSAD) (NCHRP 1-10) 1 10) JULEA (USACE, WES; used in LEDFAA) ALIZE (LCPC, France) CIRCLY (MINCAD, Australia)

19 Materials Characterization Stiffness (stress/strain) Asphalt mixes; time of loading and temperature effects. Van der Poel, Heukelom, Klomp (Shell s) Fine-grained soils, untreated aggregates; (Resilient Modulus, Mr), H. B. Seed S. F. Brown, G. F. Dehlen,, R. G. Hicks, R. D. Barksdale

20 W. Heukelom

21 H. B. Seed

22 S. F. Brown

23 G. L. Dehlen

24 R. G. Hicks

25 R. D. Barksdale

26 Material Characterization Permanent deformation Vertical compressive subgrade strain G. M. Dormon (1962) Vertical compressive stress, untreated materials M. Thompson, H. Maree

27 Subgrade Strain Criteria log ε v N = A 1 ε v b log N 7

28 G. M. Dormon

29 M.R. Thompson

30 Materials Characterization Fatigue-asphalt asphalt concrete Shell/Nottingham Univ. P. S. Pell, R. N. J. Saal (1960, 1962) UC Berkeley C. L. Monismith, K. E. Secor (1958, 1961) Fracture-asphalt asphalt concrete Shell, Heukelom

31 P.S. Pell

32 Fatigue Relationships at Constant Temp N = A 1 σ 0 b N = C 1 ε 0 d

33 Fatigue Strain vs. Load Applications log ε t ε 0 N f log N

34 Fatigue Testing Shell Amsterdam W. Heukelom and A. Klomp (1960 s) W. van Dijk (1970 s) France Shell LCPC

35 Fatigue Testing TRRL UK CSIR South Africa The Asphalt Institute, U.S. Others

36 LCPC, France & Nottingham Equipment

37 SHRP-Developed Equipment

38 Australian Beam Fatigue Apparatus (based on SHRP equipment)

39 Asphalt Concrete Fatigue Considerations Mode of Loading Controlled-stress Controlled-strain Dissipated Energy Temperature Effects Cumulative Damage Shift Factor Endurance Limit

40 Cumulative Damage Linear sum of cycle ratios Suggested by K. Peattie (Shell, 1960) Load effects, J. Deacon (1965) Temperature effects, Pell, Taylor, MacElvaney (circa 1970)

41 Fatigue - Endurance Limit log e t ~10 8 log N

42 Shift Factor, SF Factor to relate laboratory test data to field performance (usually some specific amount of wheel path surface cracking; e.g. > 45%, 10%)

43 Fatigue Relationships M-E E Design NCHRP I-10B I (F. Finn) log 10 N ( ) = t mix 45 % log log ε t = tensile strain, in./in S mix = mix stiffness,psi 10 ε S 10 log N ( ) [ % = 1. 4 log 10 N( 10%) ]

44 Fatigue Relationships The Asphalt Institute M-E E Design log 10 ( 45 %) C N where C = 10 M M V asp = Vair V + asp

45 Fatigue Relationships Shell International N M-E E Design 1 1 ( ) = SF K S 1 σ α ε E * t 5 K 3 K 1σ = f (mix volumetrics, PI α = f (t AC ) K 3 = f (t AC ) PI asp )

46 Perpetual Pavement Design Concepts } 4 to 6 1½ 3 inches of SMA, OGFC or Superpave Zone of High Compression High Modulus Rut Resistant Material Max Tensile Strain Flexible Fatigue Resistant Material 3 4 Pavement Foundation

47 Design Example: Full-depth Section, I-710 Freeway Rehabilitation

48 Design Approach Materials selection, mix design Use of SHRP developed RSST-CH (vs. Stabilometer) Structural section design Perpetual pavement example SHRP developed fatigue test Contractor required to supply results of same mix tests for proposed mix

49 Mix Design - Rutting Input N supply supply Performance test N demand demand Traffic No N supply M x N demand Yes

50 Simple Shear Test

51 Simple Shear Test Results 0.1 Permanent Shear Strain % RSST Repetitions

52 N demand Design ESALs - first five years 30 x 10 6 ESALs N demand = 660,000 M x Design ESALs x TCF x SF M = 5 TCF = SF = 0.04 *Mix with PBa-6a* binder

53 Design Binder Content 10,000,000 1,000,000 Temperature = 50 C PBA 6A AR 8000 γ p = 5 % 100,000 10, ,000 repetitions 146,000 repetitions 1, Asphalt content (percent by weight of aggregate)

54 Applications of RSST-CH

55 Applications of RSST-CH Mix design 30 Rut Depth, mm mm ARHM GG 62 mm ARHM GG 75 mm DGAC AR mm PBA 6A , , , ,000 HVS Load Applications

56 Rut Depth Estimation Use of Shear Stress and Strain Compound Loading: Time hardening

57 Pavement Representation Asphalt Concrete E AC, v AC 50 mm (2 in) τ,γ e Base E base, v base ε v Subgrade E sub, v sub

58 Inelastic Strains in Asphalt Concrete Under simple loading (effect of shearing stress, elastic shearing strain and load repetitions) γ i = a exp(b τ) γ e n c Under compound loading a j = a exp(b τ j ) γ e j γ i 1 = a 1 [ n 1 ] c γ i j = a j [(γ j-1 i /a j )(1/c) + n j ] c

59 Compound Loading - Time Hardening Inelastic strain - n relationship for larger load 10th Inelastic Strain 2nd 4th 3rd 6th 5th 8th 7th 9th Inelastic strain - n relationship for smaller load 1st Number of Load Applications

60 Surface Rutting Due to Shear within Asphalt Concrete rd = K γ K i j, where K = shift factor K = f (HMA layer thickness)

61 0.5 inches) Surface rutting due to deformation of unbound materials The Asphalt Institute subgrade strain criterion for 0.5-inch surface rutting N N = ε With time hardening, rd = d n e d = f /[ ε ] e rd 1 = d [ n 1 ] e rd j = d j [(rd j-1 /d j ) (1/e) + n j ] e (for Asphalt Institute criterion, f =

62 Structural Pavement Design Considerations Asphalt Concrete ε t Base ε v Subgrade

63 Input Structural section (full-depth) Traffic (200 million ESALs) Environment (T = 20 C) Trial mixes & pavement sections Mix fatigue data

64 Input Reliability (M=5) f(traffic estimate & testing variability) Performance criterion wheel path cracking 10%

65 Fatigue Test Results 1.E+08 1.E+07 N f 1.E+06 1.E+05 1.E+04 AR 8000, 4.7% AC, 6% AV AR 8000, 5.2% AC, 3% AV PBA 6A, 4.7% AC, 6% AV PBA 6A, 5.2% AC, 3% AV 1.E E 04 Mean Strain 1.00E 03

66 Final Design 25 mm % air voids 6% 3% AR OGFC PBA 6A (4.7%) AR 8000 (4.7%) AR 8000 (5.2%) (rich bottom) subgrade

67 Materials Conference Sessions, Categories of Papers Analysis/Design Test sections, Instrumentation Construction Maintenance Life Cycle Costs

68 Materials Subgrade soil stiffness HMA characteristics Aging Fatigue response Anisotropic behavior HMA mix type selection

69 Analysis/Design Design Experience Europe Canada U.S.: Ohio, Kansas, Oregon, Pennsylvania Pakistan Afghanistan China

70 Analysis/Design Analysis VECDFE pavement analyses Multismart3D Multi-body dynamic modeling Evaluation of HMA endurance limit

71 Test Sections, Instrumentation Test Sections Canada U.S.: Ohio, Kansas, Oregon, China Instrumentation Seasonal monitoring Strain gages

72 Construction, Maintenance, Life Cycle Costs Construction Afghanistan Maintenance UK Other European (ELLPAG) Life cycle costs

73 Additional Emphasis Construction Maintenance-long term Performance-Based Specifications-QC/QA considerations Truck pavement interaction; dynamic loading effects vs. smoothness (e.g,dedicated( truck lanes) Linking pavement design/materials/construction data with pavement management systems

74 Construction Urban vs. rural freeway rehabilitation Construction alternatives (e.g. CA4PRS) Construction management Construction quality requirements Quality assurance

75 Maintenance Materials Environment Construction Traffic

76 Performance-Based Specifications Construction control More testing? QC/QA PWL vs. performance-based requirements (pay factors)

77 Asphalt content influence on rutting Simulated ESALs to 10% rutting (15mm or more rut depth) expressed as fraction of target ESALs As-constructed average asphalt content (%) As-constructed standard deviation of asphalt content (%)

78 Asphalt content influence on pavement fatigue performance Estimated fatigue life (multiple of target (ESALs at 90% reliability) As-constructed average asphalt content (%) As-constructed standard deviation of asphalt content (%)

79 Simulated ESALs to 10% rutting (15 mm or more rut depth) expressed as multiple of target ESALs Air-void content influence on mix rutting As-constructed average air-void content (%) Asconstructed standard deviation Of air void content (%)

80 Air-void content influence on pavement fatigue performance Estimated fatigue life (multiple of target ESALs at 90% reliability) As-constructed average air-void content (%) As-constructed standard deviation of air-void content (%)

81 Pay Factors: Relative Performance (RP) Performance Characteristics Asphalt content Air void content P 200 /t AC Rutting + 0.5% RP = % RP = % RP = 0.75 Fatigue + 0.5% RP = % RP = in. RP = 0.84

82 Linking pavement design/materials/construction data to pavement management systems

83 Concept for Linking Databases Electronic PMS Data Base Electronic Materials & Construction Data Base Electronic Performance Analysis Data Base Pavement Design Traffic Information Climate & Environment PERFORMANCE ANALYSIS FOR VARIOUS CONDITIONS

84 Linking Databases, Examples WSDOT WebWSPMS MDDOT HMA construction data to PMS (AAPT, 2003)

85 Truck pavement interaction Pavement smoothness/roughness effects of dynamic loading on: Pavement damage Truck damage Goods damage Fuel consumption, tire wear, etc. WesTrack experience

86 Summary Many useful developments since about 1960 to assist in design and construction of perpetual pavements Stringent construction practices required Skilled engineers, technicians, and construction personnel required Excellent records and tracking of performance essential

87 Acknowledgement The author thanks the California Department of Transportation, which sponsored some of the work reported herein; and he also expresses his appreciation to the UC Berkeley PRC Staff for their many contributions. The materials presented are those assembled by the author and do not necessarily represent the views of the sponsor.