FULL-DEPTH HMA PAVEMENT DESIGN

Transcription

1 FULL-DEPTH HMA PAVEMENT DESIGN Marshall R. Thompson Department of Civil Engineering University of U-C

2 FULL-DEPTH HMA FULL QUALITY HMA

3 IDOT & FULL-DEPTH HMA PAVEMENT (FD-HMA)

4 BEFORE 1989 *AASHTO SN DESIGN * FEW FD-HMAS!!!

5 SN =a 1 *T 1 + a 2 *T 2 Class I SURFACE a Class I BINDER a

6 IN 1989: *M-E DESIGN ADOPTED BY IDOT FOR FD-HMA *IHR-510 MECHANISTIC EVALUATION OF ILLINOIS FLEXIBLE PAVEMENT DESIGN PROCEDURES

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8 SINCE 1989: FD-HMA

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10 FULL-DEPTH HMA PAVEMENT T AC ASPHALT CONCRETE (E HMA ) e AC SUBGRADE (E Ri )

11 HMA M-E DESIGN CONCEPTS HMA Repeated Bending Leads to Fatigue Cracking Base Subgrade Repeated Stress - Strain Leads to Rutting

12 ASPHALT CONCRETE T HMA SUBGRADE DESIGN HMA FATIGUE HMA RUTTING SUBGRADE RUTTING

13 HIGH ESAL PAVEMENTS SUBGRADE RUTTING NORMALLY NOT A PROBLEM WORKING PLATFORM ESSENTIAL FOR PAVING!!!!!

14 HMA RUTTING

15 NCAT TEST TRACK ORIGINAL CONSTRUCTION RECONSTRUCTION

16 ORIGINAL MILL/INLAY STRUCTURAL

17 NCAT TEST TRACK

18 HMA RUTTING *MATERIALS SELECTION (AGGREGATES ASPHALT) *MIXTURE DESIGN (SUPERPAVE) *CONSTRUCTION QC/QA RUT RESISTANT!!!

19 HMA FATIGUE

20 AASHTO TP 8-94 Standard Test Method for Determination of the Fatigue Life of Compacted HMA Subjected to Repeated Flexural Bending

21 FATIGUE DESIGN Tensile Strain at Bottom of Asphalt Tensile Strain in Flexural Beam Test Other Configurations

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23 FATIGUE TESTING Tensile Strain in Flexural Beam Test Other Configurations 10 Hz Haversine Load, 20 o C, Controlled Strain

24 Stiffness, mpa. STIFFNESS CURVE Failure E E E E E E E E E+07 Number of Load Cycles

25 Tensile Strain LABORATORY ALGORITHM 0.01 K1 = Intercept K2 = Slope E E E E E+10 Load Repetitions

26 HMA FATIGUE ALGORITHM N f = K1(1/e) K2

27 AC FATIGUE N = K1(1/e AC ) K2 K2 >K2 LOG e AC K1 K2 LOG N K2 K2

28 HMA FATIGUE N = K1 (1 / e AC ) K2 K2: 3.5-6

29 CURRENT IDOT HMA FATIGUE ALGORITHM N = 5E-6 * (1 / HMA STRAIN) 3.0

30 K2 OTHER STUDIES U of Illinois Maupin Results Myre FHWA Finn Linear (U of Illinois) Linear (Maupin Results) Linear (Myre) Linear (FHWA) Log(K1)

31 K1 K2 RELATIONS U of IL (IHR-39) IDOT HMAS LOG K1 = ( K2) / 0.329

32 UofI/IDOT HMA FATIGUE DATA SUMMARY Minimum K2: % K2: > 4.0 Average K2: 4.5

33 N = K1(1/HMA STRAIN) K2 HMA IDOT K2 k2 K2 STRAIN (1989) (цє) MESALS

34 THERE IS NO UNIQUE HMA FATIGUE ALGORITHM!!!!

35 TRADITIONAL M-E DESIGN

36 MINER S P i N N i Ti 100 n FAILURE : P i 100 i 1

37 MINER S N f 12 i Ni N f = TOTAL PAVT. LIFE N i = PAVT. LIFE-MONTH i

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39 Flexural Strain, micro strain LOW STRAIN TESTING Mixes Tested for Endurance Limit Micro Strain Limit 10 1.E+00 1.E+05 1.E+10 1.E+15 1.E+20 1.E+25 1.E+30 1.E+35 1.E+40 Load Repetitions, E 50

40 Tensile Strain FATIGUE ENDURANCE LIMIT 0.01 K1 = Intercept K2 = Slope E E E E E+10 Load Repetitions

41 FATIGUE ENDURANCE LIMIT Damage and Healing Concepts and Test Data Support a Strain Limit Below Which Fatigue Damage Does Not Accumulate Strain Limit Is Not The Same for All HMAs.

42 Significance of Fatigue Endurance Limit.such a limit would provide a thickness limit for the pavement..increasing the thickness beyond the limiting thickness would provide no increased structural resistance to fatigue damage and represent an unneeded expense. Prof. Carpenter

43 e AC (LOG) HMA FATIGUE N = K1 1 / e AC ) K2 FATIGUE DAMAGE NO FATIGUE DAMAGE ENDURANCE LIMIT N (LOG)

44 FATIGUE ENDURANCE LIMIT IDOT DATA NEVER < 70 micro-strain!!! GENERALLY: micro-strain MAY BE > 100 micro-strain

45 e AC (LOG) HMA FATIGUE N = K1 1 / e AC ) K2 70 me *Monismith and McLean ( 72 AAPT) ENDURANCE LIMIT PERPETUAL PAVEMENT N (LOG)

46 EFFECT OF REST PERIODS SMALL REST PERIODS BETWEEN STRAIN REPETITIONS SIGNIFICANTLY INCREASES HMA FATIGUE LIFE IDOT HMA 5 SECONDS: 10 X

47 OVERLOADING HMA CAN SUSTAIN SPORADIC OVERLOADS AND RETURN TO ENDURANCE LIMIT PERFORMANCE SUBSEQUENT HMA STRAIN REPETITIONS < ENDURANCE LIMIT: DO NOT COUNT

48 M-E DESIGN OF LONG LASTING HMA PAVEMENTS

49 STRUCTURAL MODEL Stress-Dependent Finite Element ILLI-PAVE

50 ILLI-PAVE INPUTS * SUBGRADE MODULUS (E Ri ) * HMA MODULUS

51 FINE - GRAINED E R = s D / e R ~ 6 psi E Ri s d DEVIATOR STRESS

52 MODULUS CLASSES FINE-GRAINED SOILS SOIL E Ri (ksi) Qu (psi) CBR STIFF MEDIUM SOFT VERY SOFT E Ri (ksi) = 0.42 Qu (psi) - 2

53 HOT MIX ASPHALT LINEAR ELASTIC (E) E = f (Temp & Freq)

54 FULL-DEPTH HMA LOG e HMA = LOG T HMA LOG E HMA LOG E Ri e HMA : me T HMA : in. E HMA :ksi E Ri : ksi

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57 FULL-DEPTH HMA LOG s D = LOG T HMA LOG E HMA LOG E Ri s D : psi T HMA : in. E HMA :ksi E Ri : ksi

58 DEVIATOR STRESS FULL-DEPTH HMA LOG s D = LOG T HMA LOG E HMA LOG E Ri s D : psi T HMA : in. E HMA : ksi E Ri : ksi E Ri = 5 ksi E AC = 500 ksi T AC

59 SEASONAL EFFECTS HMA MODULUS VARIES!! HMA e VARIES!! HMA FATIGUE LIFE VARIES!! MUST CONSIDER IN M-E DESIGN

60 ASPHALT INSTITUTE EQUATION TAI RR-82-2 (1982) E HMA = f (X 1, X 2, X n ) P 200 = % - # 200 V V = % AIR VOIDS h 70 F = ABSOLUTE VISCOSITY (poise x 10 6 ) P AC = % ASPHALT (wt. of mix) t p f = TEMPERATURE ( F) = FREQUENCY (Hz)

61 PG GRADE EFFECTS HMA MODULUS (ksi) TEMP ( o F) Asphalt: 3.5 % AV: 4 % - # 200: 3 % f = 10 hz

62 PG HMA MODULUS (ksi) TEMP ( o F) HMA-4.0 %* HMA-3.5 %** * AV: 2.5 % ** AV: 4.0 % - # 200: 3 % f = 10 hz

63 ASPHALT INSTITUTE PROCEDURE MMPT ( o F) = MMAT [1 + (1 / {Z + 4})] [34 / {Z + 4}] + 6 Z: INCHES FROM SURFACE

64 CHAMPAIGN, IL MONTH MMAT ( o F) MMPT ( o F) JAN /30.4 FEB /37.9 MAR /46.6 APR /59.5 MAY /73.9 JUN /82.9 JUL /84.9 AUG /82.3 SEP /74.1 OCT /62.5 NOV /46.8 DEC / inches ICM/AI

65 Pavement Design Concepts Fatigue Resistant Asphalt Base Minimize Tensile Strain with Pavement Thickness Thin Asphalt Pavement = Higher Strain Higher Strain = Shorter Fatigue Life Compressive Strain Strain Indefinite Fatigue Life Tensile Strain Fatigue Life

66 AXLE LOADING 20-Kip Single 34-kip Dual/Tandem

67 TYPICAL INTERSTATE (AASHTO 2002 Guide) * 80% -90% / 18-Wheelers * 2.5% Singles > 18 kips * 1% > 20 kips

68 PERPETUAL PAVEMENT (70 MICRO-STRAIN / 9 kips) (SUBGRADE E Ri - 5 ksi) HMA MODULUS (ksi) HMA THICKNESS (inches)

69 PERPETUAL PAVEMENT RUBBLIZED PCCP HMA OVERLAY DESIGN CONCEPTS FOR RUBBLIZED PCCP M. R. Thompson TRB RECORD # (Basis for IDOT Design)

70 PERPETUAL PAVEMENT RUBBLIZED PCCP (70 MICRO-STRAIN) HMA MODULUS (ksi) HMA THICKNESS (inches)

71 DESIGN PRINCIPLES FOR LONG LASTING HMA PAVEMENTS (M. Thompson & S. Carpenter) International Society for Asphalt Pavements Symposium on Design & Construction of Long Lasting Pavements Auburn, AL (6-04)

72 IL TEMPERATURE REGIONS REGION JULY MMAT ( F) NORTHERN 73 CENTRAL 75.8 SOUTHERN 78.2

73 JULY MMPT HMA MODULI REGION HMA MODULUS * (ksi) North Central South * / / 70-22

74 HMA THICKNESS FOR 70 Micro-Strain REGION 9-Kip T HMA (inches) * 10-Kip T HMA (inches)* North Central South * / / 70-22

75 SUMMARY & CONCLUSIONS HMA FATIGUE + NO UNIQUE FATIGUE ALGORITHM (90% IDOT K1s > 0.4) + HMA DISPLAYS A FATIGUE ENDURANCE LIMIT (FEL) + FEL > 70 MICRO-STRAIN + REST PERIODS ARE HELPFUL + LIMITED OVERLOADS NOT CRITICAL

76 SUMMARY & CONCLUSIONS (Continued) PAVEMENT DESIGN + HMA MODULUS & THICKNESS ARE DOMINANT FACTORS + AI PROCEDURE O.K. FOR MMPT + DESIGN ELP FOR HOTTEST MONTH + AVAILABLE DATA/INFO CONFIRM VERACTIY OF PROCEDURE + MAX HMA THICKNESS FEL

77 IDOT/UI TEAM CURRENTLY: * REVIEWING * UPDATING * REVISING IDOT S BUREAU D/E HMA PROCEDURE

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