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Darwin-ME Status and Implementation Efforts_IAC09

Design Guide Implementation Team

MEPDG Darwin-ME

Status and

Implementation Efforts

Idaho Asphalt Conference

October 22, 2009


What’s Being Used (2007 survey)

Asphalt Design:


Hawaii

Alaska

Does SHA Use or Plan to Use MEPDG DARWIN-ME?

N0 -12

YES - 40

2007 Survey


Hawaii

Alaska

Timeframe for Implementation

Using 3

2007 Survey

Delaware:

Project Analysis

2



Why change ??


AASHO Road Test (late 1950s)

(AASHO, 1961)

Ottawa, Illinois


1950s

Construction

Methods...

(AASHO, 1961) Design Guide Implementation Team

1950s Vehicle Loads...

(AASHO, 1961)

3



Data

Limits

(AASHO

Road

Test)

Current

Designs

>100

million<2 million

AXLE LOAD REPETITIONS

PA

VE

ME

NT

TH

ICK

NE

SS

Current design traffic

is far beyond road

test limits

Limitations AASHTO Loadings


Maximum Asphalt layer thickness at the AASHO Road Test?

0

1

2

3

4

5

6

7

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

AASHO Rod Test Sections

Asp

hal

t L

ayer

Th

ickn

ess

(in

)


Thickness Distribution of MEPDG Calibration Sections

0

2

4

6

8

10

12

14

16

18

1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 101 106

Section

As

ph

alt

Th

ick

ne

ss

(in

)


Practical Design Aspect (Conceptual)

0

2

4

6

8

10

12

14

50 60 70 80 90 100

Relaibility

Th

ickn

ess

4



y = 0.8166Ln(x) - 4.5483

R2 = 0.9721

0

2

4

6

8

10

12

14

16

18

20

100,000 1,000,000 10,000,000 100,000,000 1,000,000,000

Traffic (ESALs) to Failure

PC

C T

hic

kn

ess

PCC AASHTo '72

PCC MEPDG

Log. (PCC MEPDG )

50% Reliability Analysis


Cumulative Differences

0

2

4

6

8

10

12

14

50 60 70 80 90 100

Relaibility

Thic

knes

s

y = 0.8166Ln(x) - 4.5483

R2 = 0.9721

0

2

4

6

8

10

12

14

16

18

20

100,000 1,000,000 10,000,000 100,000,000 1,000,000,000

Traffic (ESALs) to Failure

PC

C T

hic

knes

s

PCC AASHTo '72

PCC MEPDG

Log. (PCC MEPDG )

+ =

Big difference in thickness at high ESAL design and exaggerated

at high reliability levels


MEPDG DARWIN-ME from Research to Reality

“The MEPDG is an analysis tool, not a

pavement design program.”

– Various Unnamed Sources

DARWIN -ME


Engineering Judgment

And Policy decisionsTraffic Data

Files

Training

PMS and

Local Calibration

5


Design Guide Implementation Team17

Prep-ME

Arkansas Software Capabilities:

Import Raw Data

Traffic Data Check

Interpolate Climate and Traffic Data

Retrieve Material Data

• Dynamic Modulus

• CTE

• Mr


Software Capabilities-Import Raw Data

Climate: icm files

Traffic: AHTD Traffic Monitoring Data


Software Capabilities-Traffic Data Check


Software Capabilities-Materials E*

6



Software Capabilities- Retrieving Data


Software Capabilities-Geo-Mapping Utility


Software Capabilities-Generated Files


Use the experts in your Backyard…………

Arkansas DOT contracted with University of Arkansas

Dr. Kevin Hall

Indiana DOT contracted with INDOT Research / Purdue University

Dr. Tommy Nantung

7



Indiana DOT HMA Materials Characterization

Dynamic Modulus

• District - 6

• Nom Max Aggregate Size - 3

• Binder Type – 3

• Binder Characterization

• 3 Binders DSR data

• Traffic Data

• WIM Station Data Analyzed

• Load Spectra defined by Volume


Sensitivity of Inputs for Concrete

Parameter Roughness FaultingPercent Slabs

Cracked

Permanent Curl/Warp Effective

Temperature DifferenceVS VS VS

Joint Spacing VS VS VS

Dowel Bar Diameter MS MS NS

Pavement Thickness S MS VS

Modulus of Rupture S NS VS

Modulus of Elasticity S NS VS

20-year/28-day Ratio S NS VS

Indiana DOT: MEPDG Guide for Designers

What to Change for Design?


Local Calibration Potential

All models can be adjusted (Tools,

Calibration, Coefs.)

Key effect: Eliminate “bias” of

prediction (significant over

prediction or under prediction of

distress).

Possible effect: Reduce residual of

prediction (depends on quality of

data).

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.00 0.05 0.10 0.15 0.20 0.25 0.30

Measured mean transverse joint faulting, in

Pre

dic

ted

me

an

tra

nsve

rse

join

t fa

ultin

g, in

R2 = 0.74

SEE = 0.025 in

N = 43


Statistical Optimization

S Err = (xip – xim) = 0

1

1

Bias

Bias

Make Model

Unbiased

Measured Distress

Pre

dic

ted

Dis

tre

ss

8



A few thoughts on calibration:

• Step 1: Become comfortable with MEPDG as it stands

• Step 2: Does it reflect current pavement performance?

• Use actual performance data & engineering experience

• Results from MEPDG will be different than AASHTO 93

• Step 3: Is there a bias in MEPDG prediction ?

• Step 4: Does the MEPDG capture special material

properties ?

• OGFC, SMA, Polymer, WMA, Rubber Asphalt, etc…

• Unique Structural Design


Good Calibration and Implementation Document

Montana DOT

http://www.mdt.mt.gov/research/projects/pave/pave_model.shtml

Major Findings:

• Preservation Practice Extend Performance

• Most models adequate for design

• Re-calibrate unbound materials rutting


Continual Improvement

• Continued MEPDG Validation


S11– As Built – Rut Depths

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

11

/9/2

00

6

12

/9/2

00

6

1/8

/20

07

2/7

/20

07

3/9

/20

07

4/8

/20

07

5/8

/20

07

6/7

/20

07

7/7

/20

07

8/6

/20

07

9/5

/20

07

10

/5/2

00

7

11

/4/2

00

7

12

/4/2

00

7

1/3

/20

08

2/2

/20

08

3/3

/20

08

4/2

/20

08

5/2

/20

08

6/1

/20

08

7/1

/20

08

7/3

1/2

00

8

Date

Ru

t D

ep

th,

mm

0.E

+0

0

1.E

+0

6

2.E

+0

6

3.E

+0

6

4.E

+0

6

5.E

+0

6

6.E

+0

6

7.E

+0

6

8.E

+0

6

ESALs

S11

MEPDG

at Auburn University

9



S11– As Built – Fatigue Cracking

0

5

10

15

20

25

30

35

40

10

/10

/20

06

1/1

8/2

00

7

4/2

8/2

00

7

8/6

/20

07

11

/14

/20

07

2/2

2/2

00

8

6/1

/20

08

9/9

/20

08

12

/18

/20

08

3/2

8/2

00

9

Date

Bo

tto

m-U

p F

atig

ue

Cra

ckin

g,

% o

f L

an

e

MEPDG

Measured



Continued Validationat Auburn University


What about Polymers?


Strain Response

Looking at Strains Directlyat Auburn University

10



0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0 100.0 200.0 300.0 400.0 500.0

Microstrain

Pe

rce

nti

le

Average

+15

-15

N3 2003

N4 2003

N3 2006

N4 2006


Darwin-ME

output


Training Opportunities

NHI #131064 – Introduction to Mechanistic Design

NHI #131109 - Using Mechanistic-Empirical Pavement Design Guide Software

NHI #132040 – Geotechnical Aspects of Pavements

NHI #151018 – Application of Traffic Monitoring Guide


Training / Collaboration Opportunities

FHWA Regional WIM/Traffic Workshop

– Boise, Idaho Sept 2009

FHWA Resource Center on request training

MEPDG Regional Meetings

Look out for DARWIN- ME roll out

Summer 2010


Previous & On-Going Studies

NCHRP 1-41 – Models for Predicting Reflection Cracking

of HMA Overlays (2008)

NCHRP 1-42A – Models for Predicting Top-Down

Cracking of HMA Layers (2008)

NCHRP 9-29 – Simple Performance Tester for

Superpave Mix Design (2008)

NCHRP 9-38 – Endurance Limit of HMA Mixtures to

Prevent Fatigue Cracking (2008)

NCHRP 9-44 – Develop Plan for Validating an Endurance

Limit for HMA (2008)

NCHRP 9-44A – Validating an Endurance Limit for HMA

11




SHRP 2 Project R-21 – Composite Pavement Systems

NCHRP 1-46 – Development of AASHTO Pavement

Handbook (2008)

NCHRP 1-47 – Sensitivity Analysis of MEPDG (2011)

NCHRP 4-36 – Characterization of Cementitiously

Stabilized Layers for Use in Pavement Design

and Analysis (not awarded)



Calibration Documents:

• NCHRP Digest 284, December 2003; Refining the

Calibration & Validation of HMA Performance Models: An

Experimental Plan and Database.

• NCHRP Digest 283, December 2003; Jackknife Testing –

An Experimental Approach to Refine Model Calibration and

Validation.

FHWA: Use of PMS data for local calibration.

FHWA: Use of deflection basin data in the MEPDG.


What is DARWin ME going to look like?

• Runtime Improvement

• 35-45 minutes to less than 15 minutes

• Thickness Optimization

• Database Structure

• New GUI Interface

• Backwards Compatible with earlier MEPDG versions

• Stand Alone EICM

• Sensitivity Analysis

• Enhanced Batch Mode features and reports

• Structural response output

• SI Units

No Fundamental

Theory Changes


Perspective

•1960 – Completion of Road Test Experiment

•1961-62 AASHO Interim Guide of Rigid and Flexible Pavements

•1972 AASHTO Interim Guide for the Design of Pavements

•1981 Revised Chapter III on PCC Pavement Design

•1986 Guide for the Design of Pavement Structures

•1993 Revised Overlay Design Procedures

•1998 Supplement to Concrete Design Procedures

Darwin-ME

Coming to a computer

near you:

January 2011

12



$4,317