Post on 01-Feb-2018
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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