S1SP ARA0127-1
MEPDG Development in Colorado
Rocky Mountain Asphalt Conference & Equipment ShowSession: Making Our Pavements Last
February 19, 2009Harold L. Von Quintus, P.E.
Expanding the Realm of Possibility2
Outline1. Past-Present-Future2. Colorado’s MEPDG—The Plan3. Examples—LTPP Sites4. Designing & Building
Pavements that Last Longer5. Summary
Expanding the Realm of Possibility3
The Past: 2001; Developed first road map for
implementing MEPDG in Colorado; CAPA-DOT effort.
2006, Updated Road Map.
The Present: 2008; Issued RFP to Execute the Road Map.
The Future 2009-2011; Execution of Road Map;
3-year implementation effort.
Expanding the Realm of Possibility6
Colorado’s MEPDG—The Plan 2009 to 2010; Data collection & input
determination, 80+ test sections Materials Testing and Characterization Traffic Analyses Performance Analyses
2010 to 2011; Data analysis & calibration/validation Create Input libraries Determine local calibration values
2011; Documentation & Design Manual Continuous Training
Expanding the Realm of Possibility7
Colorado’s MEPDG—The PlanExperimental Factors: Type of Structure1. Conventional Flexible Pavements2. Depth Strength Flexible Pavements3. Full-Depth HMA Pavements4. HMA Overlay of Flexible Pavements5. HMA Overlay of Intact PCC Pavements6. HMA Overlay of Fractured PCC Pavements
LTPP test sections & other roadway segments; pavement management sections.
Expanding the Realm of Possibility8
Colorado’s MEPDG—The PlanExperimental Factors: Rehabilitation Strategies
of Flexible Pavements1. Simple overlay with & without milling2. Chip coat prior to overlay3. Hot in place recycling4. Cold in place recycling
Experimental Factors: Climate Elevation/temperature
Secondary Factors:Neat, PMA, & SMA mixes; with & w/o RAP; stabilized
soils; etc.
Expanding the Realm of Possibility9
Colorado’s MEPDG—The Plan2. AASHTO; MEPDG
Calibration Guide
Document has been submitted to NCHRP with demonstrations & examples.
1. AASHTO; MEPDG Manual of Practice
Two primary documents used in validation-
calibration of MEPDG.
Expanding the Realm of Possibility12
Examples—LTPP Test SectionsInput
ParameterConvent.
HMAConvent.
HMA
ATB, Deep-
Strength
SPS-5; RAP & Virgin
RoadwayCraig, Rte. 40
Montrose, Rte. 50
La Junta, Rte. 50
Limon, IH-70
Climate North West
West Central
South East
East Central
Traffic, AADTT 176 1012 680 1860
HMA, in. 4.1 4.6 10.72.0
(Overlay)Soil A-4 A-6 A-7-6 A-7-6
Expanding the Realm of Possibility13
Examples—Rut Depth
00.10.20.30.40.50.60.70.8
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Age, years
Rut
Dep
th, i
nche
s
08-1029, Craig
08-1029, Craig,Predicted08-1053, Montrose,Predicted08-2008, La Junta,Predicted08-1053, Montrose
08-2008, La Junta
00.05
0.10.15
0.20.25
0.30.35
0 2 4 6 8 10
Age, years
Rut
Dep
th, i
nche
s
08-0506, Virgin,Predicted08-0502, RAP,Predicted08-0506, Virgin
08-0502, RAP
MEPDG Version 1.0 – Globally Calibrated
What is the accuracy of current design method?
0
0.1
0.2
0.3
0.4
0.5
0.6
0 0.2 0.4 0.6 0.8
Measured Rut Depth, inchesPr
edic
ted
Rut D
epth
, inc
hes
08-1029, Craig Line of Equality 08-1053, Montrose08-2008, La Junta 08-0502, RAP 08-0506, Virgin
Expanding the Realm of Possibility14
Examples—Fatigue Cracking
0
10
20
30
40
50
0 5 10 15 20 25 30 35
Age, years
Fatig
ue C
rack
ing,
per
cent
of
tota
l lan
e ar
ea
08-1029, Craig, Predicted
08-1029, Craig
08-1053, Montrose,Predicted08-2008, La Junta,Predicted08-1053, Montrose
08-2008, La Junta
MEPDG Version 1.0 – Globally Calibrated
0
10
20
30
40
50
60
0.00 10.00 20.00 30.00 40.00 50.00 60.00
Measured Fatigue Cracking, % Lane AreaPr
edic
ted
Fatig
ue C
rack
ing,
% L
ane
Area
08-1029, Craig Line of Equality 08-1053, Montrose08-2008, La Junta. 08-0502, RAP 08-0506, Virgin
What is the accuracy of current design method?
0
10
20
30
40
50
60
0 2 4 6 8 10
Age, years
Fatig
ue C
rack
ing,
% T
otal
Lan
eA
rea
08-0502, RAP, Predicted08-0506, Virgin, Predicted08-0502, RAP08-0506, Virgin
Expanding the Realm of Possibility15
Examples—Transverse Cracking
0
500
1000
1500
2000
2500
3000
3500
4000
0 1000 2000 3000 4000 5000
Measured Transverse Cracking, ft./mi.Pr
edic
ted
Tran
sver
se C
rack
ing,
ft./m
i.
Line of Equality 08-1029, Craig 08-1053, Montrose08-2008, La Junta. 08-0502, RAP 08-0506, Virgin
0200400600
800100012001400
0 2 4 6 8 10
Age, years
Tran
sver
se C
rack
ing,
ft./m
i.
08-0506, Virgin,Predicted08-0502, RAP,Predicted08-0506, Virgin
08-0502, RAP
MEPDG Version 1.0 – Globally Calibrated
0.0500.0
1000.01500.02000.02500.03000.03500.04000.04500.0
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Age, years
Tran
sver
se C
rack
ing,
ft./m
i. 08-1029, Craig
08-1029, Craig,Predicted08-1053, Montrose,Predicted08-2008, La Junta,Predicted08-1053, Montrose
08-2008, La Junta
What is the accuracy of current design method?
Expanding the Realm of Possibility16
Examples—Smoothness
0.0020.0040.0060.0080.00
100.00120.00140.00160.00180.00
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Age, years
IRI,
inch
es/m
ile
08-1029, Craig
08-1029, Craig,Predicted08-1053, Montrose,Predicted08-2008, La Junta,Predicted08-2008, La Junta
08-1053, Montrose
020406080
100120140160
0 2 4 6 8 10
Age, years
IRI,
in./m
i.
08-0506, Virgin,Predicted08-0502, RAP,Predicted080-0506, Virgin
08-0502, RAP
MEPDG Version 1.0 – Globally Calibrated
0
20
40
60
80
100
120
140
160
180
0 50 100 150 200
Measured IRI, in./mi.
Pred
icte
d IR
I, in
./mi.
Line of Equality 08-1029, Craig 08-1053, Montrose
08-2008, La Junta 08-0502, RAP 08-0506, Virgin
What is the accuracy of current design method?
Expanding the Realm of Possibility17
Examples—Summary of Results; NCHRP Projects, Rutting
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6Total Predicted Rut Depth,
inches
Mea
sure
d R
ut D
epth
, inc
hes
Kansas; SPS-1 Mid-West
Kansas; SPS-5 Mid-West
Montana, NewConstructionMontana, Overlays
SPS-1, General
SPS-5, General
MnRoads
Test Tracks
APT, Simulated Loads
Line of Equality
Kansas PM, NewConstructionKansas PM, Overlays
NCHRP Project 1-40B
Material & Mix
Specific Calibration
Factors
Expanding the Realm of Possibility18
Examples—Summary of Results; NCHRP Projects, Fatigue Cracking
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
100.00
0 20 40 60 80 100
Total Predicted Fatigue Cracking, %
Mea
sure
d Fa
tigue
Cra
ckin
g, %
Kansas; SPS-1, Mid-West
Kansas; SPS-5, Mid-West
Montana, New Construction
Montana, HMA Overlays
MT, New Construction
MT, HMA Overlays
Test Tracks
SPS-1, General
Line of Equality
Kansas PM, New Construction
Kansas PM, Overlays
NCHRP Project 1-40B
Material & Mix
Specific Calibration
Factors
Expanding the Realm of Possibility19
Examples—Summary of Results; NCHRP Projects, Transverse Cracking
0500
10001500
20002500
30003500
40004500
5000
0 1000 2000 3000 4000 5000Predicted Thermal Cracking,
ft./mi.
Mea
sure
d Tr
ansv
erse
Cra
ckin
g, ft
./mi. Kansas; Mid-West Sites,
New Construction
Kansas; Mid-West Sites,HMA Overlays
Montana, New Construction
Montana, HMA Overlays
Kansas PM, NewConstruction
Kansas PM, HMA Overlays
Line of Equality
NCHRP Project 1-40B
Material & Mix
Specific Calibration
Factors
Expanding the Realm of Possibility20
Examples—Summary of Results; NCHRP Projects, Roughness (IRI)
40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
200.0
40 60 80 100 120 140 160 180 200
Predicted IRI, in./mi.
Mea
sure
d IR
I, in
./mi.
Kansas; Mid-West Sites,New Construction
Kansas; Mid-West Sites,HMA Overlays
Montana, NewConstruction
Montana, HMA Overlays
Kansas, PM; NewConstruction
Kansas, PM; HMAOverlays
Line of Equality
NCHRP Project 1-40B
Material & Mix
Specific Calibration
Factors
Expanding the Realm of Possibility21
Colorado’s MEPDG:Designing-Building Pavement’s
that Last Longer
Life Cycle Cost Considerations
Expanding the Realm of Possibility22
Design Features & LCCFactors 1993 AASHTO MEPDG
Simple/Less Costly
Diversity of Conditions
Colorado Calibration; Roadway Segments
Accuracy of Method
Climatic Effects
Material Properties - Site
Time Effects on Properties
Expanding the Realm of Possibility23
Design Features & LCC
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Measured Rut Depth - Companion Sections, Neat Mixtures, inches
Mea
sure
d R
ut D
epth
- PM
A Se
ctio
ns, i
nche
s
0
20
40
60
80
0 10 20 30 40 50 60 70 80
Measured Fatigue Cracking - Companion Sections, Neat Mixtures, %
Mea
sure
d Fa
tigue
Cr
acki
ng -
PMA
Sect
ions
, %
Pavements with PMA mixtures
have less distress than those with
neat HMA mixtures.
Asphalt Institute Report; Calibration
Factors for PMA Mixes.
2007 Colorado Study found similar
results.
Expanding the Realm of Possibility24
Design Features & LCC
010203040506070
6 7 8 9 10 11 12
Effective Asphalt Content by Volume, %
Pred
icte
d Fa
tigue
Cra
ckin
g,
%
12.5 mm Mix
010203040506070
6 7 8 9 10 11 12
Effective Asphalt Content by Volume, %
Pred
icte
d Fa
tigue
Cra
ckin
g,
%
37.5 mm Mix
0
0.2
0.4
0.6
0.8
1
6 7 8 9 10 11 12
Effective Asphalt Content by Volume, %
Pred
icte
d H
MA
Rut
Dep
ths,
in.
37.5 mm Mix
0
0.2
0.4
0.6
0.8
1
6 7 8 9 10 11 12
Effective Asphalt Content by Volume, %
Pred
icte
d H
MA
Rut
Dep
ths,
in.
12.5 mm Mix
Mixture Design & Distress Predictions
Integration of Structural & Mixture Design!
Expanding the Realm of Possibility25
Design Features & LCC
01020304050607080
0 5 10 15 20 25 30 35 40
Age, months
Pred
icte
d Fa
tigue
Cra
cks,
%To
tal L
ane
Are
aDesign Voids; B-Fine Graded Limestone High Voids Low Voids
0
0.2
0.4
0.6
0.8
1
0 5 10 15 20 25 30 35 40
Age, monthsPr
edic
ted
Rut
Dep
th, i
nche
s
Design Voids, B-Fine Graded Limestone High Voids Low Voids
Construction Properties
(Air Voids) & Distress
Predictions
Expanding the Realm of Possibility26
Design Features & LCC
Limitations (factors not considered by the MEPDG):
DurabilityWorkability Etc.
Expanding the Realm of Possibility28
Overall, global calibration factors are in the ball park for Colorado roadways (predicted vs. measured distress)!
Comprehensive tool for pavement design & analyses.
Excellent forensic tool! Optimize on design features – not just
increase pavement thickness! Accuracy can be quantified.
Summary: Colorado’s MEPDG
Expanding the Realm of Possibility29
Summary: Colorado’s MEPDGCritical Step—Determining appropriate input
values, especially for rehab.
Input libraries will be important for implementation.
Expanding the Realm of Possibility32
Colorado’s MEPDG—The PlanExperimental Factors: Pavement Layers &
Materials HMA thickness; <4, 4 to 8, >8 Binder; conventional & modified HMA; dense bituminous plant mix, Superpave, SMA Aggregate base materials; class 6 & 7 Coarse-grained; non-expansive fine-grained, &
expansive fine-grained soils Stabilized subgrade soils
Expanding the Realm of Possibility33
Colorado’s MEPDG—The PlanExperimental Factors: Secondary Factors HMA aggregate type HMA with and without RAP
Expanding the Realm of Possibility34
Colorado’s MEPDG—The PlanMaterials Testing & Characterization HMA—Input Level 2 Unbound Materials—Input Level 2, R-value; confirm R-
value versus MR relationship Existing Pavements for Rehabilitation—Backcalculate
modulus values from FWD deflection basins
Truck Traffic Characterization Normalized Truck Volume & Axle Weight Distributions—
Input Level 2, Regional values & virtual distributions.
Expanding the Realm of Possibility35
2. Inputs:•Procedures•Testing•Equipment•Policy Items
1. Experimental Plan & Database:
• Section Layout• LTPP sections• Other sections (newer, research)
3. Validation:•Distress• IRI•Sensitivity of design features
4. Calibration:•Establish new coefficients of models, if needed
•Sensitivity
5. Application:•Training & user’s manual•Concurrent designs•Default input libraries (materials, performance, traffic, etc.)
•Continuing validation of models•Catalogs of designs
MEPDG Implementation Activities
Colorado’s MEPDG—The Plan
Expanding the Realm of Possibility36
SummaryUse of PMA mixes extended the overlay service life over neat HMA mixes by:3 years – 75 percentile value6 years – 50 percentile value
Expanding the Realm of Possibility37
MEPDG & Data Integration: Effective use of available, but limited local resources.
MEPDGDatabase
M-E Based Mix Design
Expanding the Realm of Possibility38
Climate Sites AvailableStation Elevation Station ElevationAkron 4664 Grand Junction 4826Alamosa 7536 La Junta 4193Aspen 7725 Lamar 3675Burlington 4198 Leadville 9938Colorado Springs 6183 Limon 5350Cortez 5899 Meeker 6333Craig 6192 Montrose 5753Denver, DIA 5382 Pueblo 4655Denver, Cent. 5827 Rifle 5506Durango 6677 Trinidad 5749
20 Weather Stations in MEPDG!
Expanding the Realm of Possibility39
N u m b e r o n M a p
E x p e r i m e n t N u m b e r
L T P P I D . N u m b e r
C o m m e n t
1 S P S - 3 0 8 A 3 0 0 2 G P S - 1 0 8 1 0 5 3 S e a s o n a l S i t e 3 S P S - 3 0 8 B 3 0 0 O u t o f S t u d y 4 G P S - 2 0 8 2 0 0 8 O u t o f S t u d y 5 S P S - 5 0 8 0 5 0 0 6 S P S - 8 0 8 0 8 0 0 7 G P S - 1 0 8 1 0 2 9 8 G P S - 1 0 8 1 0 5 7 O u t o f S t u d y 9 G P S - 1 & 6 B 0 8 1 0 4 7 O u t o f S t u d y
1 0 G P S - 6 A & 6 C 0 8 6 0 0 2 1 1 G P S - 6 A 0 8 6 0 1 3 1 2 G P S - 7 A & 7 S 0 8 7 0 3 5 1 3 G P S - 7 A 0 8 7 0 3 6 O u t o f S t u d y 1 4 G P S - 6 A 0 8 7 7 8 0 1 5 G P S - 2 & 6 B 0 8 7 7 8 1 1 6 G P S - 6 A 0 8 7 7 8 3
1 ,2
8
1 6
7
9
1 4
1 2
61 1
1 3
5
1 01 5
3 ,4
Expanding the Realm of Possibility40
Data Collection – Forensic Investigations
1. Establish test segments.
2. Recover materials for testing.
3. Cores & trenches for crack propagation & layer rutting.