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)

0

10

20

30

40

50

60

70

80

90

100

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

4

Long Life Concrete PavementLong Life Concrete Pavement

Structural designFatigue life of concrete slab must be minimizedAASHTO DARWin-ME Design Procedure Useful

5

Long Life Concrete PavementLong Life Concrete Pavement

Materials durability

Concrete slabDowels & TiebarsBase course

6

Ice crystals

Long Life Concrete PavementLong Life Concrete Pavement

Construction qualityConcrete qualityDowels and tiebar placement accurateBase course quality

7

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

9

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

10

11

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

12

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

13

Pavement CharacterizationPavement CharacterizationFor Each Layer:

Physical propertiesThermal propertiesHydraulic properties

ConcreteBase

Subbase

Subgrade

Base

14

Structural Analysis is Finite Element Based Structural Analysis is Finite Element Based (ISLAB2000)(ISLAB2000)

15

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

17

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

18

Transverse JointsTransverse Joints

Need for dowels.Benefit of larger dowels.Transverse joint spacing.

19

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

20

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

21

Joint Spacing Effect: CA ProjectJoint Spacing Effect: CA Project

Pavement Age, years

0

20

40

60

80

100

0 5 10 15 20 25 30 35

Percent Slabs Cracked

5.9 m

3.8 m

22

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.

23

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

24

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

25

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

26

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

27

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

30

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

31

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.

32

Climatic Factors Slab Curling/WarpingClimatic Factors Slab Curling/Warping

Positive temp. gradient

Bottom Up Cracking

Negative temp. gradient& shrinkage of surface

Top Down Cracking

33

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.

34

Slab BuiltSlab Built--In In temperature temperature gradient during gradient during construction at construction at time of settime of set(solar radiation)(solar radiation)

35

Curing of Concrete Curing of Concrete —— Effect CrackingEffect Cracking

0

5

10

15

20

25

30

35

0 5 10 15 20 25

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

36

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

0

2

4

6

8

10

12

1050

012

500

1450

016

500

1850

020

500

2250

024

500

2650

028

500

3050

032

500

3450

036

500

3850

040

500

4250

0

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

39

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

54

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

7

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

7

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

63

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

64

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

65

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

66

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

68

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)

0

10

20

30

40

50

60

70

80

90

100

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