perpetual pavement design - apa-mi.org pavement design an introduction to the perroad program. dave...
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Michigan Asphalt Conference2016
Perpetual Pavement DesignAn Introduction to the PerRoad
Program
Dave TimmAuburn University / NCAT
Dave NewcombTexas A&M Transportation Institute
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Overview
Pavement design background Layered elastic theory
Perpetual pavement design philosophy Sensitivity Study
Program basics Example problems Design simulations
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WHY ARE PERPETUAL PAVEMENTS IMPORTANT?
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Perpetual Pavement Award Started by the Asphalt Pavement Alliance in 2001. Road must be >35 years old. No thickness increase >4 inches. No overlay interval less than 13 years. Nominated by DOT.
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Washington State Performance
0
200
400
600
800
1000
0 - 10 11 - 20 21 - 30 31 - 40 41 - 50 51 - 60 61 or More
Age (Years)
Lane
Mile
s
HMA (Lane Miles)PCCP (Lane Miles)
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Washington State Performance
0
200
400
600
800
1000
1200
0.0 - 0.5 0.5 - 1.0 1.0 - 1.5 1.5 - 2.0 2.0 - 2.5 2.5 - 3.0 3.0 - 3.5 3.5 - 4.0 4.0 - 4.5 4.5 - 5.0 5.0 orMore
IRI (m/km)
Lane
Mile
s
HMA (Lane Miles)PCCP (Lane Miles)
Description PSR Rating IRI NHS Ride Quality
Very Good 4.0 170 in/mi)
Less than Acceptable (>2.7 m/km)
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Material Usage
Save 32% Save 28%
Save 31% Save 28%
Chart1
9346
6732
HMA, tons
Sheet1
Conv.Perp. Pvmt.
93466732
Chart1
2337
1683
RAP, tons
Sheet1
Conv.Perp. Pvmt.
23371683
Chart1
9827
6698
Aggregate, tons
Sheet1
Conv.Perp. Pvmt.
98276698
Chart1
350
252
Binder, tons
Sheet1
Conv.Perp. Pvmt.
350252
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Perpetual Pavement versusConventional Design
Chart1
7.259
10.511
15.2512.5
18.7513.5
20.514
22.514
AASHTO
PerRoad
Traffic, ESAL
HMA Thickness, in.
Sheet1
0.111050100200
AASHTO7.2510.515.2518.7520.522.5
PerRoad91112.513.51414
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A City in Texas Asphalt Performance Problems Ban Asphalt?
9
A City in Texas
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Goal of Perpetual Pavement Design Design the structure such that there are no deep
structural distresses Bottom up fatigue cracking Structural rutting
All distresses can be quickly remedied from surface
Result in a structure with Perpetual or Long Life
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Avoid These!
April 21, 2014 Panel Briefing 11
Bottom-Up Fatigue
Structural Rutting
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Surface Distresses Only
Non-Structural Rutting
Top Down Cracking
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Pavement Design: Where were we?
Using 1960s performance equations 1950s type of load Thin pavement structures (Max. 6 HMA) Meaning of structural coefficients Limited reliability analysis Some movement to M-E
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AASHO Road Test
Trucks
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M-E Design Framework
WESLEA ,
Transfer Function(s)
f
Structural Parameters
Load Configurations
=i
i
NfnDn
D>1?
D
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1 2 3
BeforeLoading During
Loading
AfterLoading -
Same Sizeas BeforeLoading
How an Elastic Material Behaves.
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Dynamic Modulus Test
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HMA Modulus VersusTemperature
10
100
1000
10000
0 20 40 60 80 100 120
Temperature, F
Mod
ulus
, 100
0 ps
i
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Soil Modulus Testing
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Effect of Moisture Content
1
10
100
0 5 10 15 20
Moisture Content, %
Mod
ulus
, ksi
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M-E Design Framework
WESLEA ,
Transfer Function(s)
f
Structural Parameters
Load Configurations
=i
i
NfnDn
D>1?
D
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M-E Design Framework
WESLEA ,
Transfer Function(s)
f
Structural Parameters
Load Configurations
=i
i
NfnDn
D>1?
D
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Layer 1HMA
E1Layer 2
Granular BaseE2
Layer 3Subgrade Soil
E3
h1
h2
No bottom boundary, assume soil goes on infinitely.
Nohorizontalboundary, assumelayersextendinfinitely.
Tire has a total load P, spread over a circulararea with a radius of a, resulting in a contactpressure of p.
PavementReactions
Deflection ()
Tensile Strain (t)
Compressive Strain (v)
Three Layer Systems
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M-E Design Framework
WESLEA ,
Transfer Function(s)
f
Structural Parameters
Load Configurations
=i
i
NfnDn
D>1?
D
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Fatigue Transfer Function
Horiz
onta
l Ten
sile
Stra
in ( i
n./in
.10
)
Load Applications (N )f
3
10 10 10 10 10 103 4 5 6 7 8
10
100
1,000
10,000
log N = 15.947 - 3.291 log ( ) - 0.854 log ( )f t
10-6
E
10
-6
E = 200,000 psi(1,380 MPa)
E = 500,000 psi(3,450 MPa)
-6
Horizontal Tensile Strain ( in./in.10 )
f
f
3
E
10
Load Applications (N )
log N = 15.947 - 3.291 log ( ) - 0.854 log ( )
E = 200,000 psi
(1,380 MPa)
(3,450 MPa)
E = 500,000 psi
-6
10
t
10,000
1,000
100
10
8
7
6
5
4
3
10
10
10
10
10
10
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Rutting Transfer Function
Ver
tical
Com
pres
sive
Stra
in (
in./i
n. 1
0 )
N = 1.077 x 10 ()
10 10 10 10 10 103 4 5 6 7 8100
1,000
10,00
100,00
f
-6
4.484310 v
Load Applications (N )
18
f
-6
-6
Vertical Compressive Strain ( in./in. 10 )
v
-6
N = 1.077 x 10 ()
18
10
4.4843
f
Load Applications (N )
f
100,000
10,000
1,000
100
8
7
6
5
4
3
10
10
10
10
10
10
-
0
200
400
600
800
1000
1200
1000 100000 10000000 1.1E+08
Number of Loads to Failure
Stra
in, (
10E-
06)
Endurance Limit
Normal Range forFatigue Testing
0
200
400
600
800
1000
1200
1000 100000 10000000 1.1E+08
Number of Loads to Failure
Stra
in, (
10E-
06)
Endurance Limit
0
200
400
600
800
1000
1200
1000 100000 10000000 1.1E+08
Number of Loads to Failure
Stra
in, (
10E-
06)
Endurance Limit
Normal Range forFatigue Testing
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M-E Design Framework
WESLEA ,
Transfer Function(s)
f
Structural Parameters
Load Configurations
=i
i
NfnDn
D>1?
D
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Structural/Performance Analysis Initial trial design
Initial estimate of layer thickness Required repairs to the existing pavement Pavement materials characterization
Analyzed by cumulative damage incrementally over time using Structural response Performance models
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Perpetual Pavement Design
No Damage Accumulation
Log N
Log
ThresholdStrain
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Tandem Axles
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60 70 80Axle Group Weight, kip
Axl
es /
1000
Hea
vy A
xles
0 50 100 150 200 250 300 350
Axle Group Weight, kN
Rural InterstateRural Principal ArterialRural Minor ArterialRural Major CollectorRural Minor CollectorRural Local CollectorUrban InterstateUrban Other Freeways and ExpresswaysUrban Principal ArterialUrban Minor ArterialUrban Collector
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PerRoad 3.3 Sponsored by APA Developed at Auburn University / NCAT M-E Perpetual Pavement Design and Analysis Tool
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Coming Refinement Currently a single fatigue endurance limit is used. Results in one-size fits all overly conservative Use FEL Ratio. Use distribution of strains.
Ratio = FELn/FELlab
April 21, 2014 Panel Briefing 39
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PerRoadXPress
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Vehicle Type Distributions
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PerRoadXPress
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DownloadPerRoad 3.3
AndPerRoadXpress
Free!
Go To:www.asphaltroads.org
ORGoogle David Timm at Auburn University
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www.asphalttechnology.org/membership
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At the 2016 AAPT Meeting:
Leading Edge Workshop: Cracking Tests 5 Presentations on Cracking Tests Symposium: Balanced Mix Design 5 Presentations on High RAP/RAS Implementation of Specifications Aging Behavior Forum Topic: World Asphalt Market
Perpetual Pavement DesignAn Introduction to the PerRoad ProgramOverviewWhy are Perpetual Pavements Important?Perpetual Pavement AwardWashington State PerformanceWashington State PerformanceMaterial UsagePerpetual Pavement versusConventional DesignA City in TexasGoal of Perpetual Pavement DesignAvoid These!Surface Distresses OnlyPavement Design: Where were we?Slide Number 14Slide Number 15Slide Number 16Dynamic Modulus TestHMA Modulus VersusTemperatureSlide Number 19Soil Modulus TestingEffect of Moisture ContentSlide Number 22Slide Number 23Slide Number 24Slide Number 25Slide Number 26Fatigue Transfer FunctionRutting Transfer FunctionSlide Number 29Slide Number 30Structural/Performance AnalysisPerpetual Pavement DesignSlide Number 33PerRoad 3.3Slide Number 35Slide Number 36Slide Number 37Slide Number 38Coming RefinementPerRoadXPressVehicle Type DistributionsPerRoadXPressSlide Number 43Slide Number 44At the 2016 AAPT Meeting: