Sensitivity Analysis forEarly-Age Cracking on

Jointed Concrete PavementEstimated with HiperPav

for Caltrans

October, 2001

EB. Lee, V. Lamour, JH. Pae, J. Harvey

Pavement Research CenterUniversity of California, Berkeley

� 3-Stage Research Plan� Sensitivity Analysis for Early ageCracking on Concrete PavementEstimated with HiperPav

� Validation and Critique of HiperPav

� Non-Destructive Concrete Testing withMaturity Meter

� Calibration and Validation

� Monitoring Performance of ConcretePavement with Testing Instruments

� Seasonal and Long-term Performance

� Research CollaborationHQ/D8/UCB/FHWA

� Instrument Testing Experiment� 4 Projects (6 sites) in D8 (2001– 2004)

� Thermocouples, Strain Meters,Weather Station, JDMD (LVDT), MDD

� Remote Data Download throughCell-phones

� D8 Projects List

4/02 - 7/02305 PCC15BakerSBd4'th9/02 - 6/04290 PCC9/02 - 6/04290 PCC15Victor.SBd3'rd2/02 - 9/02260 PCC

11/01 - 11/02204 Polarset91River.Riv2'nd11/01 - 7/02280 PCC40LudlowSBd1'st

ConcretingSchedule

Slab ThicknessCement typeRouteCityCountyTentative

Priority

� Volumetric change

� Stress creation (friction+curling)

� Fracture

Joint

Cracks

L

c

� A very complex problem (couplings !)� hydration, drying shrinkage, fracture

phenomena very difficult to predict� Chemo-thermo-mechanical modeling

� What kind of approach can help ?� Consider separately the major phenomena

through simplified prediction tools basedon experimental data

� Link the models together and assess theeffect of each factor

� Validate the global model

� Approaches� Mechanistic-empirical procedure� Sequence of prediction models

� Temperature (F.E.M.)� Material properties (through maturity)� Strains (drying, thermal, curling)� Stresses (elasticity)� Cracking (elastic fragile)

� Advantages� Provides a simplified integrated global approach to the

problem� Has been Validated with some field experiments� User-friendly and Fast� Helps finding guidelines for minimizing early-age

cracking in a particular situation

FHWA+

Transtec

Mix Design Parameters� Cement Type� Lab Maturity Data� Coarse Aggregate Type� Cement Content� Silica Fume Content� Type F Fly Ash Content� Ground Slag Content� Water Content Coarse/

Fine Aggregate Content� Water Reducer� Super Water Reducer� Retarder� Accelerator

Construction Parameters� Curing Method� Time of Day of Construction� Initial PCC Mix Temperature� Age of Opening to Traffic� Age at Sawcutting� Initial Sub-base Temperature

General DesignParameters

� Sub-base Type� Slab Base Friction� Transverse Joint Spacing� PCC Flexural Strength� PCC Modulus of Elasticity� Slab Thickness

EnvironmentalParameters

� Air Temperature� Distribution� Relative Humidity

Distribution� Overcast Conditions� Average Wind Speed

`

Concrete Temperature Demec Points Strain Gages Thermocouples

Weather Station LVDT’s Pulse Velocity Push-off Test

Push-Off Test (Friction Coefficient)

� Simplified models (Diffusion of water,microstructure of concrete, couplings,fracture mechanics ?)

� Range of validity not clearly established(HSC, FSHCC, chemical admixtures… ?)

� Short-term prediction of cracking� No cumulative damage, effect of loading ?� Deterministic simulation

provides qualitative information in acertain validity range

Sensitivity Analysis w/ HiperPav� Total Analysis Matrix to Represent CA.

� Total 186,624 Cases� R2 x D18 ×××× M16 ×××× C36 ×××× E9 = 186,624� Manual Analysis Needs 3 Graduates x 6 Months

� Batch-mode (Customized) HiperPav� 48 hours Running time (1G Hz Pentium PC)

� Statistical Analysis� Ratio Mode and Failure Mode� Use S-Plus as a Statistical Analysis Tool� Analyze 93,312 Cases: Overall, 3 Regions (DG,LA, SF)

� Identify Relative Impact of Parameters

� Seek Improvement to Prevent Early ageC ki

� Design Parameters� Design Reliability: 50%� Sub-base: HMAC-smooth, HMAC-rough, CSB� Joint Spacing: 2.7m, 4.2m, 5.7m� Thickness of Pavement: 229mm, 305mm� 18 Cases = 3 x 3 x 2

� Mix Design Parameters� Cement Type: Slow (Type II), Rapid (TypeIII)

� Aggregate Type: Granite, Gravel� Strength Gained� F Fly Ash Content� 16 Cases = 2 x 2 x 2 x 2

3.8@10DM1

4.5@10DM2

15%FA

3.8@10DM3

4.5@10DM4

25%FA

Gravel

3.8@10DM5

4.5@10DM6

15%FA

3.8@10DM7

4.5@10DM8

25%FA

Granite

Type II

2.8@12HM9

3.1@12HM10

NoFA

2.8@12HM11

3.1@12HM12

25%FA

Gravel

2.8@12HM13

3.1@12HM14

NoFA

2.8@12HM15

3.1@12HM16

25%FA

Granite

TypeIII

Mix Design

Strength unit: MPa

15% FA 3.8 MPa@10d

15% FA 4.5 MPa@10d

25% FA 3.8 MPa@10d

25% FA 4.5 MPa@10d

15% FA 3.8 MPa@10d

15% FA 4.5 MPa@10d

25% FA 3.8 MPa@10d

25% FA 4.5 MPa@10d

M1 M2 M3 M4 M5 M6 M7 M8JCP Mix design parameters

Ce me nt type type II type II type II type II type II type II type II type IICoarse Aggre gate type Grave l Grave l Grave l Grave l Granite Granite Granite Granite

Ce me nt conte nt (kgs/m3) 261 287 230 254 261 287 230 254Class C Fly ash Conte nt (kgs/m3) 0 0 0 0 0 0 0 0Class F Fly ash Conte nt (kgs/m3) 46 51 77 85 46 51 77 85

Ground S lag Conte nt (kgs/m3) 0 0 0 0 0 0 0 0Wate r Conte nt (kgs/m3) 169 169 169 169 169 169 169 169

Coarse aggre gate Conte nt (kgs/m3 1153 1153 1153 1153 1153 1153 1153 1153Fine aggre gate Conte nt (kgs/m3) 732 705 726 699 732 705 726 699

Che mica l admixture s none none none none none none none none

Total (kgs/m3) 2361 2365 2356 2360 2361 2365 2356 2360

Lab.28D Te nsil S tre ngth (MPa) 2.9 3.5 2.9 3.5 2.9 3.5 2.9 3.5Lab. 28D PCC Elasticity (GPa) 26.1 29.9 26.1 29.9 26.1 29.9 26.1 29.9

w/c 0.65 0.59 0.73 0.67 0.65 0.59 0.73 0.67w /cm 0.55 0.50 0.55 0.50 0.55 0.50 0.55 0.50

Fc28 for ACI Mix de sign (MPa) 30 40 30 40 30 40 30 40Maximum S ize o f Aggre gate (mm 19 19 19 19 19 19 19 19

Cas e A: Type II Grave l Granite

No FA 2.8 MPa@12h

No FA 3.1 MPa@12h

25% FA 2.8 MPa@12h

25% FA 3.1 MPa@12h

No FA 2.8 MPa@12h

No FA 3.1 MPa@12h

25% FA 2.8 MPa@12h

25% FA 3.1 MPa@12h

M9 M10 M11 M12 M13 M14 M15 M16JCP Mix design parameters

Ce me nt type type III type III type III type III type III type III type III type IIICoarse Aggre gate type Grave l Grave l Grave l Grave l Granite Granite Granite Granite

Ce me nt conte nt (kgs/m3) 422 529 507 576 422 529 507 576Class C Fly ash Conte nt (kgs/m3) 0 0 0 0 0 0 0 0Class F Fly ash Conte nt (kgs/m3) 0 0 169 192 0 0 169 192

Ground S lag Conte nt (kgs/m3) 0 0 0 0 0 0 0 0Wate r Conte nt (kgs/m3) 169 169 169 169 169 169 169 169

Coarse aggre gate Conte nt (kgs/m3) 964 949 1153 1153 964 949 1153 1153Fine aggre gate Conte nt (kgs/m3) 773 759 407 328 773 759 407 328

Che mica l admixture s noneWate r

re duce r

S upe r Wate r

Re duce r

S upe r Wate r

Re duce rnone

Wate r re duce r

S upe r Wate r

Re duce r

S upe r Wate r

Re duce r

Tota l (kgs/m3) 2329 2406 2405 2419 2329 2406 2405 2419

Lab.28D Te nsil S tre ngth (MPa) 4.0 4.5 5.0 5.7 4.0 4.5 5.0 5.7Lab. 28D PCC Elasticity (GPa) 32.9 35.8 39.3 43.0 32.9 35.8 39.3 43.0

w/c 0.40 0.32 0.33 0.29 0.40 0.32 0.33 0.29w/cm 0.40 0.32 0.25 0.22 0.40 0.32 0.25 0.22

Fc28 for ACI Mix de sign (MPa) 48 57 69 83 48 57 69 83Maximum S ize o f Aggre gate (mm) 19 19 19 19 19 19 19 19

Cas e B: Type III Grave l Granite

� Environmental Parameters� Region: Bay (SF), Costal (LA), Desert(Daggett)

� Season: Feb., May, Sep.� 9 Cases = 3 x 3

� Construction Parameters� Curing Method: None, Double Liquid, Burlap� Construction Start Time: 6am, 2pm, 10pm� Curing and Saw-cutting Application Time: 0hr-0hr, 0hr-24hr, 6hr-0hr, 6hr-24hr

� 36 Cases = 3 x 3 x 4

� Total Number of CASES Analyzed� Design Parameters: 18� Mix Design Parameters: 16� Construction Parameters: 36� Environmental Parameters: 9

Total: 18 ×××× 16 ×××× 36 ×××× 9 = 93,312 Cases

� Regional Statistical Analysis� Overall California� Daggett: Desert and Mountain Areas� Los Angeles: South Coastal Area� San Francisco: Bay Area� Sacramento: not considered in analysis (DG LA SF)

6.14Sunny29.387.956.288.8SepSacramento7.96Sunny38.391.051.379.2MaySacramento6.65Cloudy60.287.942.960.4FebSacramento

10.95Sunny54.292.655.673.2SepSF

13.63Partly Cloudy54.389.751.967.3MaySF8.63Cloudy63.094.747.059.6FebSF7.57Sunny59.390.763.676.5SepLA8.24Partly Cloudy61.090.457.569.7MayLA8.92Partly Cloudy53.289.750.965.6FebLA9.82Sunny14.946.865.796.4SepDaggett

14.21Sunny15.654.359.288.8MayDaggett

9.41Sunny28.872.941.566.3FebDaggett

Avg. WindSpeed(Mph)OvercastMin.

Humid.Max.

Humid.Min.

Temp.Max.

Temp.SeasonRegion

Ratio Mode Ratio (Safety)= Strength/Stress

� Failed (Ratio <=1.0), Counts First Failure Only

� Non-Failed (Ratio >1.0), Rules of Closest Ratio

Time

Strength

Stress

Time

Picks Closest Ratio

� Failed =1.0

� Non-Failed = 0

Time

Time

Failure =Failed Cases

Total Cases

Ratio FiguresRatio =

Strength

Stress

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

MixDesign parameters

II

III

Granite

Gravel

Cement Aggregate

Result of S-Plus

Mean of ParameterMean of Category

safer

with same scale

1.5

2.0

2.5

3.0

3.5

4.0

4.5

mea

n of

Rat

io

Category

M1

M10

M11 M12

M13

M14

M15 M16

M2

M3

M4

M5

M6

M7

M8

M9

D1

D10

D11D12

D13D14

D15D16

D17 D18

D2

D3D4

D5D6

D7

D8

D9

E1

E2

E3C1C10,12,14,22

C9,11,19,21

C13

C2,4,14,16

C15C17

C18

C19

C20

C25

C26

C27

C28

C29

C3

C30

C31

C32

C33

C34

C35

C36

C5

C6

C7

C8

MixDesign Design Environment Construction

California Case Overview

Relative Ratio Sensitivity

(C>M>D>E)

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

MixDesign parameters

II

III

Granite

Gravel

Cement Aggregate

Overall California

Main control parameter

Slow cement is safer

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement II

Granite

Gravel

15%25%

3.8Mpa10D

4.5Mpa10D

Aggregate FAsh Strength

Overall California

No significant effect of fly ashfor slow cement

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement Type III

Granite

Gravel

0%

25%

2.8Mpa12H3.1Mpa12H

Aggregate FAsh Strength

Overall California

Significant improvement due tofly ash for rapid cement

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement II

Granite

Gravel

15%25%

3.8Mpa10D

4.5Mpa10D

Aggregate FAsh Strength

Overall California

Larger impact of strength forslow cement

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement Type III

Granite

Gravel

0%

25%

2.8Mpa12H3.1Mpa12H

Aggregate FAsh Strength

Overall California

Small negative effect of strengthfor rapid cement

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Construction Parameters

Burlap

Double Liquid None

614

22

06

0

24

CuringMethod StartTime CureTime SawcutTime

Overall California

Curing Methods areExtremely Important

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Design Parameters

CSB

HMAC-Rough

HMAC-Smooth 2.7m

4.2m

5.7m

229mm305mm

SubbaseType JointSpacing Thickness

Overall California

Asphalt-Base is Betterthan Cement-Base

Larger Impact of Joint Spacing

Minor Impact of Thick.

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Environmental Parameters

Feb

May

Sep

Season

Overall California

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Mix Design Parameters

II

III

Granite

Gravel

Cement Aggregate

San Francisco Area

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Mix Design Parameters

II

III

Granite

Gravel

Cement Aggregate

Los Angeles Area

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

MixDesign Parameters

II

III

Granite

Gravel

Cement Aggregate

Daggett Area

Rapid cement safer (Radiation>>Hydration)

Less Impact of Cement

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement Type II

Granite

Gravel

15%

25%

3.8Mpa10D

4.5Mpa10D

Aggregate FAsh Strength

San Francisco Area

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement Type III

Granite

Gravel

0%

25%

2.8Mpa12H3.1Mpa12H

Aggregate FAsh Strength

San Francisco Area

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement Type II

Granite

Gravel

15%25%

3.8Mpa10D

4.5Mpa10D

Aggregate FlyAsh Strength

Los Angeles Area

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement Type III

Granite

Gravel

0%

25%

2.8Mpa12H3.1Mpa12H

Aggregate FlyAsh Strength

Los Angeles Area

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement Type II

Granite

Gravel

15%25%

3.8Mpa10D

4.5Mpa10D

Aggregate FAsh Strength

Daggett Area

Smaller Impact of Fly ashMore fly ash is slighter Better

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

Cement Type III

Granite

Gravel

0%

25%2.8Mpa12H3.1Mpa12H

Aggregate FAsh Strength

Daggett Area

Failure FiguresFailure =

Failed Cases

Total Cases

0.00

0.05

0.10

0.15

0.20

0.25

mea

n of

Fai

lure

Category

M1

M10

M2,11,12

M13

M14

M15M16

M3M4

M5

M6

M7

M8M9 D1,3,7,9

D2,4,6,8,10D11

D12D13D14D15 D16

D17D18

D5

E1E2

E3C10,12,22,24

C9,11,21,23

C14,16

C13,15C17,19

C6,8,18,20

C2,4

C25-34C1,3

C35,36

C5,7

MixDesign Design Environment Construction

California Case Overview

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Mixdesign Parameters

II

III

Granite

Gravel

Cement Aggregate

Overall California(Failure Graph)

safer

1.5

1.8

2.1

2.4

2.7

3.0

3.3

3.6

mea

n of

Rat

io

MixDesign parameters

II

III

Granite

Gravel

Cement Aggregate

Overall California(Ratio Graph)

safer

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Cement Type II

Granite

Gravel

15%25%

3.8Mpa10D

4.5Mpa10D

Aggregate FAsh Strength

Overall California

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Cement Type III

Granite

Gravel

0%

25%

2.8Mpa12H

3.1Mpa12H

Aggregate FAsh Strength

Overall California

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Factors

CSB

HMAC-RoughHMAC-Smooth

2.7m4.2m

5.7m

229mm305mm

SubbaseType

Design ParametersThickness

Overall California

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Construction Parameters

Burlap

Double Liquid None

6

14

22

0 6

0

24

CuringMethod StartTime CureTime SawcutTime

Overall California

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Environment Parameter

FebMay

Sep

Season

Overall California

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Mix Design Parameters

II

III

Granite

Gravel

Cement Aggregate

Daggett Area

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Cement Type II

Granite

Gravel

15%25%

3.8Mpa10D

4.5Mpa10D

Aggregate FAsh Strength

Daggett Area

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Cement Type III

Granite

Gravel

0%

25%

2.8Mpa12H

3.1Mpa12H

Aggregate FAsh Strength

Daggett Area

Mix Design parameters

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

II

III Granite

GravelCement Aggregate

Los Angeles Area

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Cement Type II

GraniteGravel 15%25% 3.8Mpa10D

4.5Mpa10DAggregate FlyAsh Strength

Los Angeles Area

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Cement Type III

Granite

Gravel

0%

25%

2.8Mpa12H

3.1Mpa12H

Aggregate FlyAsh Strength

Los Angeles Area

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Mix Design Parameters

II

IIIGranite

GravelCement Aggregate

San Francisco Area

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Cement Type II

Granite

Gravel 15%

25% 550psi10D

650psi10DAggregate FAsh Strength

San Francisco Area

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

mea

n of

Fai

lure

Cement Type III

Granite

Gravel

0%

25%

400psi12H

450psi12H

Aggregate FAsh Strength

San Francisco Area

BoxplotsMaybe no need to show this

(only first one or two forcomparison)

02

46

II IIICement

Overall California

02

46

Granite Gravel

Aggregate

Overall California

02

46

550psi10D 650psi10D

Strength

Overall California (Cement Type II)

02

46

15% 25%

FAsh

Overall California (Cement Type II)

02

46

400psi12H 450psi12H

Strength

Overall California (Cement Type III)

02

46

0% 25%

FAsh

Overall California (Cement Type III)

1.5

2.0

2.5

3.0

3.5

4.0

4.5

mea

n of

Rat

io

Category

M1

M10

M11 M12

M13

M14

M15 M16

M2

M3

M4

M5

M6

M7

M8

M9

D1

D10

D11D12

D13D14

D15D16

D17 D18

D2

D3D4

D5D6

D7

D8

D9

E1

E2

E3C1C10,12,14,22

C9,11,19,21

C13

C2,4,14,16

C15C17

C18

C19

C20

C25

C26

C27

C28

C29

C3

C30

C31

C32

C33

C34

C35

C36

C5

C6

C7

C8

MixDesign Design Environment Construction

California Case Overview

Relative Sensitivity Ratio

Regional Relative Sensitivity Ratio

� Construction Parameters� Mix design Parameters� Design Parameters� Environment Parameters

Relative Sensibility (%) Const. Design Envir. Mix

SF 39.8 21.6 14.8 23.9 LA 40.9 22.7 6.1 30.3

Daggett 54.7 20.0 4.2 21.1

Overall Relative Sensitivity Ratio� Higher Average Risk of early age cracking in the

desert area� Heat generation (Hydration ) is not critica l i n D.G:

Exacerbated by the external cond itions

Less Param eters Govern Cracks in D.G.

Environmental cycle

Time

Heat of hydration

Temperature

Effect of Construction Parameters� High impact of Curing

� Thermal insulation is the onlypositive effect considered byHiperpav (e.g. burlap)

� Curing time is not important asdiffusion of water is notconsidered

� High impact of sawing time� Medium impact of starting time

� 6AM≈≈≈≈2PM� 10PM safer� Additive effect of initialtemperature of subbase andexternal temperature during

� High impact of aggregate type� Mainly due to stiffness and CTE(gravel safer than granite)

� Generation of stress from strainmore important than generation ofthermal strain

� Medium impact of fly ash� Large effect on fast cement,insignificant effect on slowcement

� Probably underestimated effect(diffusion of

water+microstructure)

Effect of Mix Design Parameters

� Medium impact of tensilestrength� Slow cement concrete, higher tensilestrength is much better

� Fast cement concrete, higher tensilestrength shows slight improvement

� Competition between heat generation,development of stiffness and strengthevolution

� Low impact of cement type� Overall slow cements are safer thanrapid ones

� Low impact : Heat generation is not soimportant in the desert regions andfast cement concretes have much higherstrength (HSC).

Effect of Mix Design Parameters

� Medium impact of subbase type� Mainly due to large difference infriction coefficient

� Uncertainty of the results (basedon Push-off tests)

� Medium impact of joint spacing� Linear effect

� Low impact of thickness� Negative effect of thickness on thegradient of deformation balancedby its positive effect on thestructural behavior

Effect of Design Parameters

� Low impact of season� Low impact due to the smalldifferences in environmentalconditions

� February safer than May andSeptember

� Wind, solar insulation,temperature and humidity rangesequally important

Effect of Environmental Parameters

Interpretation of Analysis Mode� Failure Mode analysis

� Failed / Non-Failed reduction� Alters the sensitivity of eachparameterIncorrect mode of analysis

� Statistical Box analysis� Gives a better idea of thevariation for each parameter

� Similar relative variations foreach parameterConfirms the validity of the ratiomode analysis

Conclusions (I)� Use of Hiperpav

� Don′′′′t use failure analysis butratio analysis

� Trends more important thannumbers

� Accurate and useful forqualitative guidelines in a rangeof situations

� However considerations on earlyage cracking are necessary butnot sufficient for JCP durabilityprediction (mechanical, chemicaland thermal degradations after

Conclusions (II)� Qualitative guidelines

� Improvement of construction practicehas the most effective impact(sawing, curing)

� Mix design not so important in D.G.The type of aggregate is the only lever

� Mix design quite important in LA -SFUse of soft aggregate, fly ash (25%) andslower cement (coarser cement, more C2S)Higher ultimate strength (low w/c ratio)

� JCP geometry not so critical forearly age cracking without loading

� Construction time and season don′′′′t

Recommendations (I)� Changes to Hiperpav

� Modeling of Autogeneous shrinkage(HSC)

� Extension to FSHCC� Probabilistic approach� Cumulative damage approach fordurability prediction

� Determination of Input data specificto Caltrans situations

� Further validations

Recommendations (II)� Improve Caltrans Practices toPrevent Early age Cracking� Performance in Desert Area dependson Construction Practices

� Importance of aggregate type(especially in desert region)

� Mix design optimization for fly ashand lower w/c

� Safe Joint Spacing� Investigating the validity ofMaturity meter� Hiperpav Model shows Minor Impact ofchemical admixtures

Closures� Is it Worthwhile to Use HiperPavas a Design Tool?� Yes. Because it Provides a GoodIndication of the Correct Answers toComplex Problems which can not beSolved Intuitively.

� Does HiperPav Always PredictEarly age Cracking Correctly?� No. But it Provides Directions forMaking Decisions to Reduce the Riskof Early age Cracking.

Q / A&

Discussions

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