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presented to:Midwest Transportation Consortium – Transportation Seminar
11 April 2003 – Ames, IA
Advanced Pavement Materials, Analysis,and Design
presented by
Dr. Robert Otto Rasmussen, P.E.Vice President and Chief Engineer
The Transtec Group, Inc., Austin, Texas, USA
Concrete Pavement Technology
2
Concrete Pavement Research in the United States is currently focused in several areas:
Expedited Construction Practices (Fast-Track)Smoothness and Safety ImprovementsLong-Life PavementsOptimization of Materials and Construction
The Federal Highway Administration (FHWA), Concrete Industry, and the State Departments of Transportation (through TRB) are working more closely.
Introduction
3
Topics3 topics of recent research with the objective of meeting these goals:
1. Predicting Early-Age Concrete Pavement Behavior using FHWA HIPERPAV
2. Concrete Mix Optimization – The Road to a Performance-Based Mix Design System
3. Whitetopping – A Proven Overlay with a New Name
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HIPERPAVMix OptimizationWhitetopping
Outline
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HIPERPAVMix OptimizationWhitetopping
Outline
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FHWA-sponsored Research Project
State and Industry Involvement
Guidelines for Fast-track Jointed Concrete Pavements
orHIgh PERformance Concrete PAVing:an integrated computer system that analyzes material, environmental, design, and construction variables that will ....
HIPERPAVWhat is it?
2
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to understand 72-hour behavior
and
to predict 72-hour behavior of concrete pavements.
HIPERPAVWhat is it?
Assist Engineers and Contractors
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Mid-80’s
Concrete Paving Industry• Pave it fast• Time counts
or• Be ready to lose significant rehabilitation opportunities
After that message, over 100 trial projects were completed in US under SP 201.
HIPERPAVHow did it start?
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SP 201 (Fast-track)Findings
Very positive results with two major concerns:
1. What value to open to traffic?
2. What about temperature management? FHWA-SA-94-080
HIPERPAVHow did it start?
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Hot mixes; cold days? Blankets? Yes? No? Thermal shock?Curling & warping? Strength gain and opening time? Saw cutting and cracking? Internal stresses?
Fast-track Findings
HIPERPAVHow did it start?
11
65°F
58°F
8:00 AM
75°F
HIPERPAV Paving Operations
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Time
PCC Temp
HIPERPAV
8:10 AM
Paving Operations
3
13
Time
PCC Temp
HIPERPAV
8:30 AM
Curing
14
Time
PCC Temp
Heat Conductionto/from the subbase
Convection
Overcast ConditionsSolar Radiation
HIPERPAV
9:00 AM
Environmental Influences
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Time
PCC Temp
Generated Heat from Hydration
HIPERPAV
11:00 AM
Heat of Hydration
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Time
PCC TempPCC SetTime
Transition from Plastic To
Hardened State
HIPERPAV
12:00 PM
Set Time
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Time
PCC TempSlab Tends to Expand from Set
Time up to the Maximum PCC Temperature
HIPERPAV
4:00 PM
Peak Concrete Temperature
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Time
PCC TempPCC Slab Tries to Contract
HIPERPAV
6:00 PM
Cooling Begins
4
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Time
PCC Temp
Saw Cut Joints Saw Cut Joints
HIPERPAV
7:00 PM
Joint Sawing
20
Time
PCC Temp
Warm
Cold
Thermal Difference Through the Slab
HIPERPAV
11:00 AM
Curling
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Time
PCC Temp
Warm
Cold
Bottom Expands Top Contracts: Slab
Tends to Curl
HIPERPAV
9:00 PM
Curling
22
Time
PCC Temp
∆T
Slab Weight Restrains Vertical
Movement
Slab Weight
HIPERPAV
9:00 PM
Curling
23
Time
PCC Temp
∆T
Axial and Curling Restraint Lead to Crack Formation
at Joints
Formation of Cracks at Joints
Formation of Cracks at Joints
HIPERPAV
12:00 AM
Subbase Restraint
24
Time
PCC Temp
∆TAs Temperature
Decreases,
PCC Contraction Continues…
HIPERPAV
2:00 AM
Excessive Restraint
5
25
Time
PCC Temp
∆T
Mid Panel Thermal
Crack Occurs
HIPERPAV
5:00 AM
Early-Age Failure
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HIPERPAVControl Panel
27
HIPERPAVIdeal Case
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HIPERPAVIdeal Case
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Well, that’s nice…
But, what if the weather is not “ideal”?
HIPERPAV Question
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HIPERPAVCold Front
6
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HIPERPAVIdeal Case
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HIPERPAVCold Front
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What Now?
Maybe some Blankets?
HIPERPAVQuestion
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HIPERPAVCold Front
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HIPERPAVCold Front + Blankets
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What happens if I haveto open to traffic in
24 Hours?
HIPERPAVQuestion
7
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Cold Front + Blankets HIPERPAV
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HIPERPAVCold Front + Blankets (remove @ 24 hrs.)
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Is there another way?
What about aFast-Track Mix?
HIPERPAVQuestion
40
HIPERPAVCold Front
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HIPERPAVCold Front + Fast-Track Mix
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HIPERPAVDesign Inputs
8
43
HIPERPAVMix Design Inputs
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HIPERPAVEnvironmental Inputs
45
HIPERPAVConstruction Inputs
46
HIPERPAVMix OptimizationWhitetopping
Outline
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HIPERPAVMix OptimizationWhitetopping
Outline
48
Mix Optimization
Cost
Permeability
Strength
Stiffness
Workability
Coarse Aggregate
Fine Aggregate
Cement
Water
Mineral Admixtures
Chemical Admixtures
Models
“Optimum” PCC Mix
Criteria Constituents
Fibers
Plastic Shrink.
Performance
What is Optimization?
9
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☺“Yesterday”28-DayStrength
SpecRock Sand Cement
“Today” Multiple Cements
Multiple Sands
Multiple RockSources
Fly-Ashes, GGBFS,S. Fume, Nat. Pozz. Chem. Admixtures
Early Traffic Opening
Time
Warranty
PRS
Competition
Mix OptimizationMixes – Yesterday and Today
50
Multiple Cements
Multiple Sands
Multiple RockSources
Fly-Ashes, GGBFS,S. Fume, Nat. Pozz. Chem. Admixtures
All Available Materials
KnowledgeBase
ComputerizedGuidelines
2 Cements
1 Sand
2 Rock Sources
1 Class F Fly-Ash1 GGBFS 2 Chem. Admix.
Subset of Materials
CementSandRock Class FFly-Ash
Chem.Admix.
Optimum Materials
OptimumProportions
Mix OptimizationRefining our Choices
51
VariabilityCompatibility
Strength• Early-Age (< 72 hour)• “Spec” 3 to 56 Days• Long-Term (> 1 year)
Cost• Material Cost• Placement Cost• Life-Cycle Cost
MixProperties
• Coef. of Thermal Expansion• Shrinkage Potential• Stiffness / Creep Relaxation• Heat of Hydration and
Activation Energy
• Slump• Workability• Viscosity/Cohesion
Workability
Durability
• Permeability• Air Void Structure • Freeze-Thaw Susceptibility• DEF Susceptibility• ASR Susceptibility• Chemical Attack
• Fatigue Cracking Susceptibility• Spalling Susceptibility• Faulting Susceptibility• Smoothness Deterioration Potential
• Thermal Shock Potential• Plastic Shrinkage Cracking Susceptibility• Construction Smoothness PotentialDistress
Potential
Early-Age
Long-Term
Mix OptimizationProperty / Performance Targets
52
Water
Cement • Chemistry• Fineness• Blending
Unit Cost of All Constituents
Aggregates• Gradation• Chemistry and Mineralogy• Thermal Properties (CTE, Conductivity, etc.)• Hardness• Texture and Shape• Permeability, Porosity, and Density
MineralAdmixtures
• Type (Fly Ash, GGBFS, etc.)• Chemistry• Fineness
ChemicalAdmixtures
• Type (AEA, HRWR, etc.)• Chemistry• Impact on Set Time
• Crushed Concrete• Industrial Byproducts / Waste
• Type (Chemical and Physical)• Strength, Stiffness, and Bond• GeometryOther
Additives
Fibers
Recycled
Polymers
Mix OptimizationMaterials Properties and Cost
53
Fiber Dosage (% or lb./cu.yd.)
Workability(from Inverted Slump)
Fiber Type A
Fiber Type B
Fiber Type C
Mix OptimizationMaterial-Target Functions
54
Fiber Dosage(% or lb./cy)
Workability(from Inv. Slump)
Fiber Dosage(% or lb./cy)
Cost ($)
Fiber Dosage(% or lb./cy)
Long-Term Perf.(Fatigue Life)
Fiber Dosage(% or lb./cy)
Early-Age Beh.(Plastic Shrink.)
Mix OptimizationMaterial-Target Functions
10
55
Workability
DesirabilityCo
ntrac
tor100%
0%
Owne
r
Mix OptimizationDesirability Functions
☺
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Mix OptimizationDesirability Functions
Workability(from Inv. Slump)
Desirability☺
Cost ($)
Desirability☺
Long-Term Perf.(Fatigue Life)
Desirability☺
Early-Age Beh.(Plastic Shrink.)
Desirability☺
57
$
LTPerf.
Workability40%30%
10%
20%
PlasticShrinkage
Mix OptimizationWeighting Factors
58
Fiber Dosage (% or lb./cu.yd.)
Desirability100%
0%
OptimumFiber
Dosage
Mix OptimizationOverall Desirability
☺
59
HIPERPAVMix OptimizationWhitetopping
Outline
60
HIPERPAVMix OptimizationWhitetopping
Outline
11
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What is it?
Why was research needed?
What does this research provide?
Whitetopping
62
What is it?
A new concrete pavement surface atop an existing hot-mix asphalt (HMA) pavement.
Whitetopping
63
What is it?
Asphalt and Concrete...Working Together!
Whitetopping
64
Why was Research Needed?
We understand HMA pavements...
Whitetopping
65
Why was Research Needed?
For example... we know they rut...
Whitetopping
66
Why was Research Needed?
and rut...
Whitetopping
12
67
Why was Research Needed?
and rut...
Whitetopping
68
Why was Research Needed?
and rut...
Whitetopping
69
Why was Research Needed?
and rut...
Whitetopping
70
Why was Research Needed?
and rut...
Whitetopping
71
Why was Research Needed?
We also know they crack...
Whitetopping
72
Why was Research Needed?
and crack...
Whitetopping
13
73
Why was Research Needed?
and crack...
Whitetopping
74
Why was Research Needed?
We also understand PCC pavements
Whitetopping
75
Why was Research Needed?
We know they fault...
Whitetopping
76
Why was Research Needed?
We know they fault...
Whitetopping
77
Why was Research Needed?
We also know they spall...
Whitetopping
78
Why was Research Needed?
We also know they spall...
Whitetopping
14
79
Why was Research Needed?
And finally... we know they crack...
Whitetopping
80
Why was Research Needed?
And finally... we know they crack...
Whitetopping
81
Why was Research Needed?
But do we understand Whitetopping pavements???
? ?Concreteand Asphalt
Working Together
Whitetopping
82
Common Questions...
Whitetopping
83
Thin 4 in. to 8 in.Ultra-thin (UTW) < 4 in.
How thick do I build it?
Conventional 8 in. +
Whitetopping
84
How much do I saw?Whitetopping
15
85
How much do I saw?Whitetopping
86
How do I prepare the surface?
Do I mill the asphalt?
Do I use a level-up course?
If so, how much?
Whitetopping
87
Do I need Dowels, Fibers, Tie Bars?Whitetopping
88
Common Questions...
... requiring practical and reliableanswers.
Whitetopping
89
Materials Characterization Models
Hot-Mix Asphalt (HMA)Dynamic Modulus
η)f(///
abeff
beffa
HMA
ep)(ppp
)V(VV
Vp
)(ppE
log0.393532log0.3133510.60331343
283834
4
2200200
10.005470.0000170.0039580.00213.871977
0.8022080.0580970.002841
0.0017670.0292321.249937log
−−−++−++
+
+−−−
−+−=
Whitetopping
90
Whitetopping
16
91
Whitetopping
92
Whitetopping
93
Lane 5 Lane 6 Lane 7 Lane 8 Lane 9 Lane 10 Lane 11 Lane 12
Whitetopping
94
Whitetopping
95
Lane 12Lane 11Lane 10Lane 9Lane 8Lane 7Lane 6Lane 5 Lane 5 Lane 6 Lane 7 Lane 8Lane 9 Lane 10 Lane 11 Lane 12
Whitetopping
96
Lane 5 Lane 6 Lane 7 Lane 8Lane 9 Lane 10 Lane 11 Lane 12
Lane 9Lane 5Lane 6Lane 10Lane 11Lane 12Lane 7Lane 8
Whitetopping
17
97
Whitetopping
98
Lane 9Lane 5Lane 6Lane 10Lane 11Lane 12Lane 7Lane 8
05101520253035
0 5000 10000 15000 20000ALF Wheel Passes
Rut D
epth
(mm) Lane 9 Lane 5 Lane 6
Lane 10Lane 11Lane 12Lane 7
Lane 8
Whitetopping
99
Lane 9Lane 5Lane 6Lane 10Lane 11Lane 12Lane 7Lane 8
Lane 9 Lane 5 Lane 6Lane 10
Lane 11Lane 12Lane 7
Lane 8
Whitetopping
100
Lane 9Lane 5Lane 6Lane 10Lane 11Lane 12Lane 7Lane 8
Lane 9 Lane 5 Lane 6Lane 10
Lane 11Lane 12Lane 7
Lane 8
Lane 9Lane 5Lane 6
Lane 10Lane 11Lane 12
Lane 7Lane 8
Whitetopping
101
Lane 9Lane 5Lane 6Lane 10Lane 11Lane 12Lane 7Lane 8
Lane 9Lane 5Lane 6
Lane 10Lane 11Lane 12
Lane 7Lane 8
Whitetopping
102
Lane 9Lane 5Lane 6Lane 10Lane 11Lane 12Lane 7Lane 8
Lane 9Lane 5Lane 6
Lane 10Lane 11Lane 12
Lane 7Lane 8=
=======
Most-to-LeastSlab Cracking
Most-to-LeastHMA Rutting
¡ Holy Frijoles!
Whitetopping
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