diseño de pavimentos de hormigón para alcanzar larga vida ... · diseño de pavimentos de...
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Diseño de Pavimentos de Hormigón para alcanzar larga
Vida útil con Confiabilidad
Michael I. DarterMichael I. DarterEmeritus Prof. Civil Engineering, University of Illinois Emeritus Prof. Civil Engineering, University of Illinois
&&Applied Research Associates, Inc. USAApplied Research Associates, Inc. USA
October 2012October 2012Cordoba, ArgentinaCordoba, Argentina
Oldest Concrete Pavement USA Oldest Concrete Pavement USA Ohio 1891 [121 years]Ohio 1891 [121 years]
Design Life for HMA & PCC was 20 yearsDesign Life for HMA & PCC was 20 yearsUtah Survival Curves Utah Survival Curves –– II--15 (100+ miles)15 (100+ miles)
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0 5 10 15 20 25 30 35 40Age, years
Per
cen
t S
ecti
ons
Surv
ived
PCCHMA
Long Life Concrete PavementLong Life Concrete Pavement
Structural designMaterials durabilityConstruction qualityDesign Life = 40 to 100 years!
All are equally important to long life concrete pavement
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Long Life Concrete PavementLong Life Concrete Pavement
Structural designFatigue life of concrete slab must be minimizedAASHTO DARWin-ME Design Procedure Useful
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Long Life Concrete PavementLong Life Concrete Pavement
Materials durability
Concrete slabDowels & TiebarsBase course
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Ice crystals
Long Life Concrete PavementLong Life Concrete Pavement
Construction qualityConcrete qualityDowels and tiebar placement accurateBase course quality
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Construction ProblemsConstruction Problems
Dowel placementForming of jointsTie bar placementConsolidation of PCCOthers
Poor DowelAlignment
Good DowelAlignment
Tran
sver
se J
oint
Use of AASHTO DARWinUse of AASHTO DARWin--ME for Structural DesignME for Structural Designof Long Life Concrete Pavementof Long Life Concrete Pavement
Site ConditionsClimate: concrete & base durabilityExisting Pavement / Subgrade: supportTraffic: loadings
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Use of AASHTO DARWinUse of AASHTO DARWin--ME for Structural DesignME for Structural Designof Long Life Concrete Pavementof Long Life Concrete Pavement
At a given site:Slab dimensions: Length, width, thicknessConcrete: strength, modulus, thermal coefficientEdge support: extra width, tied PCC shoulderJoints: Dowel diameter, spacingBase course: type, properties, friction w/slab
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DG InputsAxle load (lb)
Materials & Construction
Structure,Joints,Reinforcement
Climate
Damage
Dis
tres
sDG Process
Distress Prediction & ReliabilityMechanistic Response Damage AccumulationTime
Dam
age
DG Outputs
Field Distress
Traffic
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DG InputsAxle load (lb)
Materials & Construction
Structure,Joints,Reinforcement
Climate
Damage
Dis
tres
sDG Process
Distress Prediction & ReliabilityMechanistic Response Damage AccumulationTime
Dam
age
DG Outputs
Field Distress
AASHTO DARWin-MEComprehensive System
Traffic
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Pavement CharacterizationPavement CharacterizationFor Each Layer:
Physical propertiesThermal propertiesHydraulic properties
ConcreteBase
Subbase
Subgrade
Base
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Structural Analysis is Finite Element Based Structural Analysis is Finite Element Based (ISLAB2000)(ISLAB2000)
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Joint Faulting= f(loads, dowels, slab, base, jt space, climate, shoulder, lane width, zero-stress temp, built-in gradient, …)
IRI= f(IRIi, faulting, cracking, spalling, soil( P-200), age, FI )
Transverse Crack= f(loads, slab, base friction, subgrade, jt space, climate,shoulder, lane width, built-in temp grad, PCC strength, Ec, shrink, …)
Design for Performance JPCP: ModelsDesign for Performance JPCP: Models
Inputs
Critical Stresses
Finite Element Model – ISLAB2000
Incremental Fatigue Damage ∑= Nn
Calibration Fatigue Damage & Field Cracking
∑ Nn
Field Cracking
Fatigue DamageFatigue Damage——Cracking Cracking
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Slab Thickness Vs. CrackingSlab Thickness Vs. Cracking
Data: AASHO Road Testplus I-80 16 years,12 million trucks
80
60
40
20
0
8 9 121110 13Slab thickness, cm
Slab
s cr
acke
d %
DARWin-ME
20 cm 25 cm 30 cm
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Transverse JointsTransverse Joints
Need for dowels.Benefit of larger dowels.Transverse joint spacing.
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Need for Dowels & DiameterNeed for Dowels & DiameterJoint faulting, in
Heavy trucks (millions)0 5 10 15 20 25
0
0.02
0.04
0.06
0.08
0.10
32 mm dowel diameter
25 mm dowel diameter
Without dowels
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Joint Spacing Effect: MN, MI, CA ProjectsJoint Spacing Effect: MN, MI, CA Projects
10 252015 30
5
10
15
20
25
0
Minnesota-10 years
Michigan-15 years
Slabs cracked, %
Slab length, ft
Midwest USA
Western USA: 21 JPCP 1970’s random joint spacing3-4 m joint spacing = 10 percent slabs cracked5-6 m joint spacing = 34 percent slabs cracked
4.6m 6m
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Joint Spacing Effect: CA ProjectJoint Spacing Effect: CA Project
Pavement Age, years
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20
40
60
80
100
0 5 10 15 20 25 30 35
Percent Slabs Cracked
5.9 m
3.8 m
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Base & Base & SubbaseSubbase Materials, ThicknessMaterials, Thickness
Base types: unbound aggregate, asphalt, cement/lean concrete.
Base modulus, thickness, friction with slab.Subbase(s): unbound aggregate, lime treated soils, cement treated soils, etc.
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Material CharacterizationMaterial Characterization
Dynamic Modulus E* of HMA base
Material modulus is a key property of each layer
Resilient Modulus Mr of Unbound Materials & Soils
Static Modulus of Concrete Slab & Cement-Treated Base
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5.Review computed outputs5.Review computed outputs
Winter
Unbound Aggregate Base Mr Vs Month
0
50
100
150
200
250
1 2 3 4 5 6 7 8 9 10 11 12
Month
Res
ilien
t Mod
ulus
, ksi
Winter
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Impact of Subgrade: JPCP FaultingImpact of Subgrade: JPCP FaultingEffect of Subgrade Modulus
0
0.010.02
0.030.04
0.050.06
0 20000 40000 60000 80000 100000 120000
Subgrade Input Mr, psi
Join
t Fau
lting
, in
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Impact of Subgrade: JPCP Cracking Impact of Subgrade: JPCP Cracking Effect of Subgrade Modulus
0
20
40
60
80
0 50000 100000 150000
Subgrade Input Mr, psi
Slab
Cra
ckin
g, %
slab
s
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Concrete Slab/Base Contact FrictionConcrete Slab/Base Contact FrictionConcrete Slab (JPCP, CRCP)
Base Course (agg., asphalt, cement)
Subbase (unbound, stabilized)
Compacted Subgrade
Natural Subgrade
Bedrock
Slab/BaseFriction
Slab & Base ThickJoint spacingTied shoulder, widenedFriction slab/base
Concrete Slab & Structure InputsConcrete Slab & Structure InputsFlex & Comp StrengthModulus ElasticityStr. & Mod. gain w/timePoisson’s Ratio
Coef. Thermal Expan.Thermal ConductivitySpecific HeatBuilt-In Thermal Grad.
Cementitious Mat’lsW/CShrinkage (drying)Unit weight
Thermal Structural
Mix Properties Design
Fatigue Capacity
Monthly Variations of Base ModulusMonthly Variations of Base Modulus
0
0.4
0.8
1.2
1.6
Aug Sep OctNov Dec Ja
nFeb Mar AprMay Ju
n Jul
Months
Elastic modulus, Mpsi
CTB ATB Unbound
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Incremental DamageIncremental Damage: Hourly, Monthly, Yearly : Hourly, Monthly, Yearly ““Everything ChangesEverything Changes”” Over LifeOver Life
Time, years
Traffic Vol
Granular Base Modulus
CTB Modulus
Each axle type & load application
2 8640
Subgrade Modulus
HMA Modulus
PCC Modulus
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ClimateClimate (temperature, moisture, solar rad., humidity, wind)(temperature, moisture, solar rad., humidity, wind)
Integrated Climatic Model (ICM)User identifies local weather stations:
Hourly temperature, PrecipitationCloud cover, Relative ambient humidityWind speed.
User inputs water table elevation.ICM Computes temperatures in all pavement layers and subgrade.ICM Computes moisture contents in unbound aggregates and soils.ICM Computes frost line.
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Climatic Factors Slab Curling/WarpingClimatic Factors Slab Curling/Warping
Positive temp. gradient
Bottom Up Cracking
Negative temp. gradient& shrinkage of surface
Top Down Cracking
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Slab Curling & Warping from Temp. & MoistureSlab Curling & Warping from Temp. & Moisture
Hourly temperature non-linear gradientsthrough slab.Monthly relative humidity changes in top of slab (changes in drying shrinkage at top of slab).Permanent Curl/Warp = Built-in Temperature gradient + permanent drying shrinkage + creep.
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Slab BuiltSlab Built--In In temperature temperature gradient during gradient during construction at construction at time of settime of set(solar radiation)(solar radiation)
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Curing of Concrete Curing of Concrete —— Effect CrackingEffect Cracking
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Age, years
-25 deg F
Severe
-10 deg F (Typical)
-3 deg F
Water or
Night
Cure
Punc
hout
s pe
r mile
Impact of PCC Construction:
Day/Night paving, Curing
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Traffic Data Collection CategoriesTraffic Data Collection CategoriesSite SpecificSite Specific1.1. AADTTAADTT2.2. Percent Percent
truckstrucks3.3. GrowthGrowth
RegionalRegional1.1. Axle load Axle load
distributionsdistributions2.2. Direction & lane Direction & lane
distribution factorsdistribution factors3.3. Monthly Monthly
distribution factorsdistribution factors4.4. Hourly distribution Hourly distribution
factorsfactors5.5. Truck type volume Truck type volume
distributionsdistributions
State WideState Wide1.1. No. axles per No. axles per
truck typetruck type2.2. Truck wanderTruck wander3.3. Tire pressure & Tire pressure &
spacingspacing4.4. Axle spacingAxle spacing5.5. Wheelbase Wheelbase
spacingspacing
Different Axle Load DistributionsDifferent Axle Load Distributions
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2
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1050
012
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1450
016
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1850
020
500
2250
024
500
2650
028
500
3050
032
500
3450
036
500
3850
040
500
4250
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United StatesChina
Axle load (lb)
Perc
ent o
f axl
es
Calibration of JPCP Performance Models
Calibration of Design ModelsCalibration of Design Models
JPCP sections from all over North AmericaTransverse fatigue cracking modelTransverse joint faulting modelIRI smoothness model were calibrated to US pavement sections.
Results used in Design Reliability to establish error of prediction
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LTPP 0214 SPS2, W of Phoenix, LTPP 0214 SPS2, W of Phoenix, MP 109, 32 Million TrucksMP 109, 32 Million Trucks
Bottom Up CrackingBottom Up Cracking(fatigue damage at slab bottom)(fatigue damage at slab bottom)
Outside Lane
Shoulder
Direction of traffic
Critical location(bottom of slab)
Top Down CrackingTop Down Cracking(fatigue damage at slab top)(fatigue damage at slab top)
Outside Lane
Shoulder
Direction of traffic
Critical location(top of slab)
Critical topCritical top--down stressesdown stresses
PCC Fatigue ModelPCC Fatigue Model
whereNi,j,k,… = allowable number of load
applications Mri = PCC modulus of rupture σi,j,k, . = applied stressC1 = calibration constant, 2.0 FieldC2 = calibration constant, 1.22 Field
( )2
,,,,,1,,,,,log
C
nmlkji
inmlkji
MRCN ⎟⎟⎠
⎞⎜⎜⎝
⎛⋅=σ
*
* ******
****** *
*
*****
** * *** ***
*****
********
**** ** *
*1E+07
1E+06
1E+05
1E+04
1E+03
1E+02
1E+01
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2.0
AASHOExtended AASHO
CORPS
N, Number of Stress Repetitions to First Fatigue Crack
Stress Ratio, (σ/MR)
N
MinerMiner’’s Fatigue Damage Models Fatigue Damage Model
WhereDIF = fatigue damage, accumulativen i,j,k,= number of applied load applications
Ni,j,k,. = number of load applications to crack
∑=onmlkji
onmlkjiF N
nDI
,,,,,,
,,,,,,
Transverse Cracking Fatigue Damage ModelTransverse Cracking Fatigue Damage Model
WhereDIF = Fatigue damage (TD or BU)n i,j,k,= Applied load applications at
condition i, j, k, l, m, nNi,j,k,. = Allowable number of load
applications at condition i, j, k, l, m, n
∑=onmlkji
onmlkjiF N
nDI
,,,,,,
,,,,,,
i = Age (months/years life) j = Month/day or night/hourk = Axle type l = Axle load levelm = Equivalent Temp gradient n = Lateral truck path
Miner’s Damage
48Concrete Sections Calibration (JPCP, OLs, CPR)
Correlation of Damage to Field CrackingCorrelation of Damage to Field Cracking
0
20
40
60
80
100
1.E-08 1.E-06 1.E-04 1.E-02 1.E+00 1.E+02
Fatigue Damage
Perc
ent s
labs
cra
cked
N = 520 observationsR2 = 84 percent
SEE = 5.72 percent
JPCP Cracking Model CoefficientsJPCP Cracking Model Coefficients
( ) 541
1CDIC
CRKF+
=
C4 & C5 were determined through statistical regression using hundreds of field JPCP projects across North America
Fatigue Cracking in Field Correlation to DamageFatigue Cracking in Field Correlation to Damage
0
20
40
60
80
100
1.E-08 1.E-06 1.E-04 1.E-02 1.E+00 1.E+02
Fatigue Damage
Perc
ent s
labs
cra
cked
( ) 541
1CDIC
CRKF+
=
Example of Measured & Predicted Slab Cracking Example of Measured & Predicted Slab Cracking
LTPP 0217, LCB
Example of Measured & Predicted Slab CrackingExample of Measured & Predicted Slab Cracking
LTPP 0214, Agg Base
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Design Reliability DARWinDesign Reliability DARWin--MEME
Design life: 1 to 100 years.Select design reliability: 50 to 99 percent
Transverse crackingJoint faultingSmoothness, IRI
Standard error based on prediction error of distress & IRI from hundreds of field pavement sections.
DARWinDARWin--ME Design ReliabilityME Design ReliabilityJPCP
RF = P [Fault < Critical Fault]RC = P [Crack < Critical Crack]RIRI = P [IRI < Critical IRI]
Design Reliability Example JPCPDesign Reliability Example JPCPExample: Project 1993-2013 = 20 years (32 million trucks in outer lane)
Design Reliability: 50, to 99.9 %Standard deviation: Error of predictionTransverse fatigue slab cracking: 10% slabsTransverse joint faulting: 0.12 inchIRI: Initial = 60 in/mile, Terminal = 150 in/mile
AZ JPCP Design Reliability EffectAZ JPCP Design Reliability Effect
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8
9
10
11
12
13
50% 61% 97.4 99.8
Slab
Thickne
ss, in.
Design Reliability, %
No fatigue cracking
Lots of fatigue cracking
Recommended Design Reliability Criteria: ArizonaRecommended Design Reliability Criteria: Arizona
Performance Criteria
Divided Highways, Freeways, Interstates
Non Divided, Non Interstate, 10,000+ ADT
2001 –10,000 ADT
501‐2,000 ADT
< 500 ADT
Design Reliability
97% 95% 90% 80 75
Design Performance CriteriaDesign Performance Criteria
What level of Distress & IRI should we design and at what level of Reliability? In general:
Strive for the “Goldilocks” level: not too high, not too low for an optimum solution!Traffic level, potential congestion from lane closure, and access to detours are clearly major factors.
Effect Slab Cracking CriteriaEffect Slab Cracking Criteria
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8
9
10
11
12
13
0 5 10 15 20 25 30
Design Slab
Thickne
ss, in
Percent Slabs Cracked Performance Criteria
Recommended Performance Criteria Recommended Performance Criteria JPCP & Composite Pavement for ArizonaJPCP & Composite Pavement for Arizona
Performance Criteria
Divided Highways, Freeways, Interstates
Non Divided, Non
Interstate, 10,000+ ADT
2001 –10,000 ADT
501‐2,000 ADT
< 500 ADT
Cracking, % Slabs
10 10 15 15 20
Faulting, mm
3 3 3 4 5
IRI, m/km 2.38 2.38 2.54 2.54 2.86
GENERAL INFO
RUNPROGRESS
PAVEMENT STRUCTURE
LAYER PROPERTIES
PERFORMANCE
EXPLORER WINDOW
ERROR LIST
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Example: Wisconsin JPCP, US 18Example: Wisconsin JPCP, US 18
25-cm JPCP, CTE=11/C, Width=4-mRandom Jt Space: 4 to 6-m
No Dowels10-cm Unbound
Aggregate Base (2.3% fines)
Natural Subgrade
Bedrock
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WS JPCP Measured Vs Predicted WS JPCP Measured Vs Predicted
Distress Existing JPCP
Slab cracking4-m = 0%6-m = 38%
Joint faulting 1.75-mm
IRI 2.3 m/km
14 years, 5.5 million trucks
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WS JPCP Measured Vs Predicted WS JPCP Measured Vs Predicted
Distress Existing JPCP MEPDG Prediction
Slab cracking4-m = 0%6-m = 38%
4-m = 0%6-m = 60%
Joint faulting 1.75-mm 2.0-mm
IRI 2.3 m/km 2.3-m/km
14 years, 5.5 million trucks
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What If . . . Modify the JPCP Design?What If . . . Modify the JPCP Design?
If we could go back and “modify” the original design, what would we do?
Add 27-mm diameter dowel bars at transverse joints.Use of 5-m uniform joint spacing.
WS JPCP Design ComparisonWS JPCP Design Comparison14 years, 5.5 million trucks14 years, 5.5 million trucks
DistressMeasured
Existing DesignPredicted
New Design
Slab cracking
4-m = 0%6-m = 38%
4.6 m = 0 %
Joint faulting1.75-mm
0.25-mmn(37-mm dowels)
IRI2.3 m/km
1.1 m/km
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DARWinDARWin--ME Analysis CapabilitiesME Analysis Capabilities
Design & Rehabilitation: many alternatives“What if” questionsEvaluation: forensic analysis Construction deficiencies: impacts on life, $Truck size and weight: cost allocationAcceptance quality characteristics: impact on performance, $
Example: CA Life Cycle AnalysisExample: CA Life Cycle Analysis
Analyses conducted during investigation of long life concrete pavements.Conducted by Prof. John Harvey of UC Davis & team.Comparison of 20, 40 and 100 years for JPCP
Traffic ClosuresTraffic ClosuresMinimal maintenance and rehabilitation would greatly reduce lane closures for work zones and maintenance causing reduced congestion & user costs, and reduced fatalities over the 100 years.
Design Parameters: Route 210 CADesign Parameters: Route 210 CA
LCCA Results for Route 210 CALCCA Results for Route 210 CA(no User Costs calculated)(no User Costs calculated)
Optimum Design LifeOptimum Design LifeWhen traffic will be heavy over much of the design life, design for as long a time period as possible for a given location.Limitations include:
Materials durabilityHarsh climate (chain wear, materials)Subgrade movement (heave, swell, settle)Desired design reliability
Design Life for HMA & PCC was 20 yearsDesign Life for HMA & PCC was 20 yearsUtah Survival Curves Utah Survival Curves –– II--15 (100+ miles)15 (100+ miles)
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0 5 10 15 20 25 30 35 40Age, years
Per
cen
t S
ecti
ons
Surv
ived
PCCHMA
Improved Pavement LongevityImproved Pavement Longevity
Life of Pavement
Acc
umul
ated
Per
cent
100
50
0
CurrentPerformance
Increased life
Performancewith improvedtechnology Design
ConstructionMaterials
Maintenance