Unique Pavement Designs with DARWin - ME

Unique Pavement Designs with DARWin - ME

Chris Wagner, PEPavement and Materials Engineer

FHWA – Resource Center

February 2011

Topics

• 3 DOT pavement design examples• Differences between DARWin – ME and

AASHTO• Validation Courtesy of NCAT• Preview of Darwin ME

CRCP Rehabilitation

I-20 Near Talladega Motor Speedway

Site Conditions:

• CRCP in fair condition with average 8 punchouts or patches per mile in the design lane

• Crack spacing 4 to 6 feet with tight non-working cracks

• Traffic Level = 3 million ESAL’s per year• Initial analysis period = 12 years

• Reliability = 95%

Case 1:

Rehabilitation / Overlay of 6 miles CRCP Pavement

SMA 3.5”Superpave Varies (2.5 – 8.5)

CRCP 9” Rubbilized and Non - Rubbilized

Black Base 6”

Stabilized Soil 5”In-situ Soil Semi-Infinite

Rubbilized CRCP

Analysis is a new HMA pavement over a strong base• Rubbilized CRCP resilient modulus

• 65,000 psi (Suggested value MEPDG MOP)• 100,000 psi (Suggested value AASHTO 93)

• Controlling design threshold is bottom up fatigue cracking

In-tact CRCP Design (Semi-Rigid Design)

Controlling criterion:

• Future punchouts per mile• Preservation of the structural integrity of the rigid base

• Minimum overlay thickness (4” – 6”)• Reduction of the temperature gradient • Reduce shear stress b/w Asphalt and CRCP• Bond between asphalt and CRCP

In-tact CRCP Design (Semi-Rigid Design)

Controlling criterion:

• Future punchouts per mile• Preservation of the structural integrity of the rigid base

• Minimum overlay thickness (4” – 6”)• Reduction of the temperature gradient • Reduce shear stress b/w Asphalt and CRCP• Bond between asphalt and CRCP

Structural Design

Empirical Design

AASHTO 93 DesignLayer Material Structural Coeff. Thickness (in) Calculated SN

1/2” SMA 0.54 1.4 0.76

¾” SMA 0.54 1.98 1.07

1” HMA 0.54 2.48 1.34

1” HMA 0.54 2.92 1.58

1” HMA 0.54 3.15 1.70

Rubbilized CRCP 0.22 9 1.98

In-Situ Black Base 0.22 6 1.32

In-Situ Stabilized Soil 0.05 5 0.25

Total 32 in 9.99

AASHTO 93 DesignLayer Material Structural Coeff. Thickness (in) Calculated SN

1/2” SMA 0.54 1.4 0.76

¾” SMA 0.54 1.98 1.07

1” HMA 0.54 2.48 1.34

1” HMA 0.54 2.92 1.58

1” HMA 0.54 3.15 1.70

Rubbilized CRCP 0.22 9 1.98

In-Situ Black Base 0.22 6 1.32

In-Situ Stabilized Soil 0.05 5 0.25

Total 32 in 9.99

12 in HMA

Performance Threshold

Performance Threshold

Structurally Adequate

Semi Rigid Pavement (In-tact CRCP)

Let’s Vote:

To Rubbilize…. …or not to Rubbilize

Pavement Design Suggestion

1. Non-Rubbilized CRCP with 6-8 inch HMA overlay

• Use SMA for top 2 layers• Use hydrated lime in all layers (granite aggregates)

• Patch all working punchouts

2. Rubbilize and HMA overlay of 10 inches• Use resonance breaker

Case 2: New Major Arterial By-pass

• DELDOT• Traffic Level = 3.25 million ESAL’s per year• Initial analysis period = 20 years = 65 Million ESAL’s

• Reliability = 95%

Figure 1: Project Loca1on

Case 2: New Alignment: Major Arterial

12.5mm Superpave HMA Wearing Course - 2”19 mm Superpave HMA Intermediate Course

2” – 6”HMA Black Base HMA Base Course

4” – 10”

Graded Aggregate Base8”

Borrow Material (A-4-4) 12”

In-situ Soil (A-6) Semi-Infinite

AASHTO 93 Design

Flexible Structural Design18-kip ESALs over Initial Performance Period = 64,924,334Initial Serviceability = 4.2Terminal Serviceability = 2.5Reliability Level = 95 %Overall Standard Deviation = 0.44Roadbed Soil Resilient Modulus = 5,000 psiStage Construction 1Calculated Design Structural Number = 7.52 in

Required HMA Thickness = 18 in

Layer Material Description

Struct Coef.(Ai)

Drain Coef.(Mi)

Thickness (Di)(in)

CalculatedSN (in)

1 Type C 0.4 1 2 0.80

2 Type B 0.4 1 6 2.40

3 BCBC 0.32 1 10 3.20

4 GABC 0.14 1 8 1.12

Total 26 7.52

MEPDG Analysis

Indiana DOT Experience

RoadAASHTO 93 Thickness Result

MEPDG Thickness ResultEs<mated Contract Saving ($)

Actual Contract Saving ($) Total Savings ($)

I-‐465 16”-‐18’ PCCP 14”-‐18’ PCCP $1,475,000

I-‐465 Ramps ( ) 12.5”-‐18’ PCCP 11”-‐18’ PCCP $112,000 $1,000,000I-‐465 Ramps ( 40/Wash. St)

12.5”-‐18’-‐PCCP 12.5”-‐18’PCCP $0

I-‐80(mainline) 16”-‐18’-‐PCCP 14”-‐18’-‐PCCP $361,000 $775,170

I-‐80(Ramp) 12”-‐18’-‐PCCP 10.5”-‐18’-‐PCCP $520,000

SR 14 15”-‐HMA 13.5”-‐HMA $333,000 $155,440

US 231 11”-‐18-‐PCCP 10”-‐18’-‐PCCP $333,000 $0

US 231-‐Ramp 10”-‐18’-‐PCCP 9.5”-‐18’-‐PCCP $28,000

US 231 15.5”-‐HMA 13”-‐HMA $557,000 $0

SR 62 16”-‐HMA 13”-‐HMA $403,000 $420,548

US 231 11”-‐18’-‐PCCP 10”-‐18’-‐PCCP $178,000 $0 4,300,000

Indiana DOT Experience

RoadAASHTO 93 Thickness Result

MEPDG Thickness ResultEs<mated Contract Saving ($)

Actual Contract Saving ($) Total Savings ($)

I-‐465 16”-‐18’ PCCP 14”-‐18’ PCCP $1,475,000

I-‐465 Ramps ( ) 12.5”-‐18’ PCCP 11”-‐18’ PCCP $112,000 $1,000,000I-‐465 Ramps ( 40/Wash. St)

12.5”-‐18’-‐PCCP 12.5”-‐18’PCCP $0

I-‐80(mainline) 16”-‐18’-‐PCCP 14”-‐18’-‐PCCP $361,000 $775,170

I-‐80(Ramp) 12”-‐18’-‐PCCP 10.5”-‐18’-‐PCCP $520,000

SR 14 15”-‐HMA 13.5”-‐HMA $333,000 $155,440

US 231 11”-‐18-‐PCCP 10”-‐18’-‐PCCP $333,000 $0

US 231-‐Ramp 10”-‐18’-‐PCCP 9.5”-‐18’-‐PCCP $28,000

US 231 15.5”-‐HMA 13”-‐HMA $557,000 $0

SR 62 16”-‐HMA 13”-‐HMA $403,000 $420,548

US 231 11”-‐18’-‐PCCP 10”-‐18’-‐PCCP $178,000 $0 4,300,000

Total Estimated Savings =

$10 Million

Practical Design Aspect (Conceptual)

0

3.25

6.50

9.75

13.00

50 63 75 88 100

Thic

knes

s

Relaibility

AASHTO ‘93MEPDG

0

5

10

15

20

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

Thi

ckne

ss

Traffic (ESALs) to Failure

PCC AASHTo '72PCC MEPDG Log.(PCC MEPDG )

50% Reliability Analysis

Cumulative Differences

0

3.25

6.50

9.75

13.00

50 63 75 88 100

Thic

knes

s

Relaibility

0

5

10

15

20

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

y = 0.8166ln(x) - 4.5483R² = 0.9721

PCC

Thi

ckne

ss

Traffic (ESALs) to Failure

PCC AASHTo '72 PCC MEPDG Log.(PCC MEPDG )

+ =

Big difference in thickness at high ESAL design and exaggerated at high reliability levels

Continued MEPDG Validation

Thanks NCAT• Dr. Dave Timm• Kendra Davis

N8 2006 Rutting

N6 2003-2006 Rutting

Rutting Measured vs. Predicted

N3 2003-2006 IRI

N9 2006 IRI

N1 2003 IRI

N1 2003 Bottom-Up Fatigue Cracking

Final Cracking Comparison

Final Cracking Comparison

MEPDG Correctly Designed 12 of 14

at 50% Design Reliability

What about Polymers?

DARWin-ME Improvements

Efficiency

Increase software speedAutomated thickness optimization

Batch modeSensitivity

Functionality

SI versionTraffic capsStability

Correct reported bugs (Task Force directed)Improve error handling

Enterprise Software

Opening Screen

Optimization

Runtime Improvements

Proj Name

Description MEPDG-v1.1 Runtime

MEPDG-v1.1 Runtime

DarwinME Runtime

DarwinME Runtime

Proj Name

Description

Overall * APADS Overall APADS

Following run+me is measured on a laptop of 32bit XP, 3 GHz, 3.5 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 3.5 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 3.5 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 3.5 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 3.5 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 3.5 GB RAM

121

New HMA:8” AC , Binder 10%, Air voids 8.5%, Granular base. 13’45” 12’21” 5’11” 4’30”

Following run+me is measured on a laptop of 32bit XP, 3 GHz, 1.0 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 1.0 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 1.0 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 1.0 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 1.0 GB RAM Following run+me is measured on a laptop of 32bit XP, 3 GHz, 1.0 GB RAM

121 New HMA:8” AC , Binder 10%, Air voids 8.5%, Granular base.

32’28” 30’00” 11’37” 9’40”

DARWin –ME is a powerful tool to make a pavement design decision

Unique Pavement Designs with DARWin - ME

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