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Asphalt Institute Method

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Mechanistic-Empirical Methodology

StructuralModels

PavementResponse

FailureCriteria

Trial Layer

Thicknesses

Material

Properties

ClimateInformation

Final LayerThicknesses

Satisfactory

TrafficInformation

Unsatisfactory

ClimateModels

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Mechanistic-Empirical Methodology

StructuralModels

PavementResponse

FailureCriteria

Trial Layer

Thicknesses

Material

Properties

ClimateInformation

Final LayerThicknesses

Satisfactory

TrafficInformation

Unsatisfactory

ClimateModels

DAMA(LEA)

maxasphalttmax subgrade c

Nf(fatigue)N

d

(rutting)

hac

hbs

Eac, Ebs, Esg

ac, bs, sg

MAAT(F)

Final LayerThicknesses

ESALS

Freeze/ThawAsphalt Temp

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Pavement Response

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Fatigue Failure Criterion

3.291 * 0.854

f t

N 0.0796 E

AsphaltTensileStrain

AsphaltFatigue

Life

AsphaltResilientModulus

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Rutting Failure Criterion

4.4779

d cN 1.365 10

SubgradeCompressive

Strain

SubgradeFatigue

Life

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Traffic

fESAL ADT T T D L G 365

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Climatic Regions

MAAT

(F)

Asphalt

Grades

Viscosity, (106poise)

Frost

Effects

45 AC-5, AC-10 0.6 Yes60 AC-10, AC-20 1.6 Possible

75 AC-40 5.0 No

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Mean Monthly Air Temperatures

Jan 45 F May 56 F Sept 78 F

Feb 38 F Jun 70 F Oct 73 F

Mar 43 F Jul 78 F Nov 58 F

Apr 45 F Aug 81 F Dec 54 F

South Carolina (MAAT = 60F)

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Pavement Temperatures

-5

0

5

10

15

20

25

30

35

40

08/01/97 08/01/98 08/01/99 08/01/00 08/01/01

Temperature(C)

Asphalt

Air

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Pavement Temperature

1 341 6

4 4p aM M

z z

Mean monthlyair temperature ( F)

Mean monthlyasphalt temp. ( F) Depth (in)

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Pavement Temperature

0

5

10

15

20

25

0 10 20 30 40 50 60 70 80 90

Temperature (F)

Depth(in)

Air AirPavement Pavement

Ground

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Asphalt Modulus

3 7

9 10 13

*1 2 200 4 5 6

log0.58 11 12

log c ca

c c f c

b

E c c P f c V c c f

c V T c c f

Vol. air

content %

Asphalt

viscosity

% passing

#200 sieve

Vol. bindercontent (%)

Asphalttemp.

Loadingfreq.

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Unbound Base Modulus

Source: WSDOT Pavement Guide Interactive CD-ROM

2

1 K

RM K

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Unbound Base Modulus

0.471 0.041 0.139 0.287 0.8682 1 2 1 3 110.447E h h E E K

AsphaltThickness

BaseModulus

BaseThickness

AsphaltModulus

SubgradeModulus

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Unbound Base Modulus

3 33

1

s s b b

s b

h E h E E

h h

s = surface courseb = binder course

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Subgrade Modulus2 Months 4 Months 5 Months1

January January

50,000 psi

4,000 psi

12,000 psi

22,500 psi

1,350 psi

7,200 psi

18,000 psi

South Carol ina

(60F MAAT)

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Asphalt Institute Method

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Asphalt Institute Method

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