13 - mechanistic-empirical design - mechanistic-empirical... · pavement response failure criteria...
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Mechanistic-Empirical Design
Asphalt Institute Method
Mechanistic-Empirical Methodology
StructuralModel
PavementResponse
FailureCriteria
Trial LayerThicknesses
MaterialProperties
ClimateInformation
Final LayerThicknesses
Satisfactory
TrafficInformation
Unsatisfactory
ClimateModel
2
Asphalt Institute Methodology
StructuralModels
PavementResponse
FailureCriteria
Trial LayerThicknesses
MaterialProperties
ClimateInformation
Final LayerThicknesses
Satisfactory
TrafficInformation
Unsatisfactory
ClimateModels
DAMA(LEA)
max asphalt t max subgrade c
Nf (fatigue)Nd (rutting)
hachbs
Eac, Ebs, Esgac, bs, sg
MAAT(°F)
Final LayerThicknesses
ESALS
Freeze/ThawAsphalt Temp
3
Pavement Response
4
Pavement Response
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h1 , E1 , 1
h2 , E2 , 2
, Esg , sg
h1 , E1 , 1
h2 , E2 , 2
h3 , Egb , gb
, Esg , sg
Pavement Response
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h1 , E1 ,
h2 , E2 ,
, Esg ,
h1 , E1 ,
h2 , E2 ,
h3 , Egb ,
, Esg ,
Fatigue Failure Criterion
3.291 * 0.854f tN 0.0796 E
AsphaltTensileStrain
AsphaltFatigue
Life
AsphaltResilientModulus
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Rutting Failure Criterion
4.4779d cN 1.365 10
SubgradeCompressive
Strain
SubgradeFatigue
Life
8
Traffic
fESAL ADT T T D L G 365
9
Climatic Regions
MAAT(ºF)
AsphaltGrades
Viscosity, (at 70ºF)
FrostEffects
45 AC-5, AC-10 600,000 Yes60 AC-10, AC-20 1,600,000 Possible75 AC-40 5,000,000 No
10
Mean Monthly Air Temperatures
Jan 45˚F May 56˚F Sept 78˚FFeb 38˚F Jun 70˚F Oct 73˚FMar 43˚F Jul 78˚F Nov 58˚FApr 45˚F Aug 81˚F Dec 54˚F
South Carolina (MAAT = 60°F)
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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
Tem
pera
ture
(C)
AsphaltAir
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Pavement Temperature
1 341 64 4p aM M
z z
Mean monthlyair temperature (˚F)
Mean monthlyasphalt temp. (˚F) Depth (in)
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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 cb
E c c P f c V c c f
c V T c c f
Vol. aircontent %
Asphaltviscosity
% passing#200 sieve
Vol. bindercontent (%)
Asphalttemp.
Loadingfreq.
14
Unbound Base Modulus
Source: WSDOT Pavement Guide Interactive CD-ROM
21 K
RM K
15
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
EffectiveModulus
BaseThickness
AsphaltModulus
SubgradeModulus
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Unbound Base Modulus
3 33
1
s s b b
s b
h E h EEh h
s = surface courseb = binder course
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Subgrade Modulus
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Subgrade Modulus2 Months 4 Months 5 Months1
January January
50,000 psi
4,000 psi12,000 psi22,500 psi
1,350 psi7,200 psi
18,000 psi
South Carolina(60°F MAAT)
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Asphalt Institute Method
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Asphalt Institute Method
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23
24
Asphalt Institute Method
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Stage 1
27
Stage 2
28
Unstaged