Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented...

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Pavement Thickness Pavement Thickness Evaluation Using Ground Evaluation Using Ground Penetrating Radar Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam Presented for Final Exam

Transcript of Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented...

Page 1: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Pavement Thickness Evaluation Pavement Thickness Evaluation Using Ground Penetrating RadarUsing Ground Penetrating Radar

Dwayne HarrisDwayne Harris

Presented for Final ExamPresented for Final Exam

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OUTLINEOUTLINE

IntroductionIntroduction Fundamentals of GPR Fundamentals of GPR Interpretation of GPR dataInterpretation of GPR data Methodologies for Thickness EvaluationMethodologies for Thickness Evaluation GPR Data QualityGPR Data Quality Validation of MethodologiesValidation of Methodologies

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IntroductionIntroduction

Background on pavement thickness Background on pavement thickness evaluationevaluation

Literature reviewLiterature review

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Significance of Thickness Significance of Thickness InformationInformation

Pavement managementPavement management Pavement performance and remaining life estimates Pavement performance and remaining life estimates

require knowledge of pavement thicknessrequire knowledge of pavement thickness Setting maintenance and rehabilitation prioritiesSetting maintenance and rehabilitation priorities Main input in overlay design Main input in overlay design INDOT Major Moves $138,483,477 budgeted for 2006 INDOT Major Moves $138,483,477 budgeted for 2006

resurfacingresurfacing Thickness of uppermost surface course needed for Thickness of uppermost surface course needed for

mill and Fill resurfacing projects.mill and Fill resurfacing projects. Pavement thickness is needed for project level FWD Pavement thickness is needed for project level FWD

structural analysis structural analysis

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National Pavement RehabilitationNational Pavement Rehabilitation

YearYear Urban Urban InterstatesInterstates

Rural Rural InterstatInterstat

Rural Rural RoadRoad

ExpenditureExpenditure

19981998 8.69%8.69%

PoorPoor

3.25%3.25%

PoorPoor

1.42%1.42%

PoorPoor

$36.3$36.3

BillionBillion

20032003 7.62%7.62%

PoorPoor

1.64% 1.64%

PoorPoor

0.76%0.76%

PoorPoor

$49.3$49.3

BillionBillion

ChangeChange 1.07%1.07% 1.61%1.61% 0.66%0.66% 36%36%

[Hartegen, 2005]

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Technologies Used for Pavement Technologies Used for Pavement Thickness EvaluationThickness Evaluation

CoreCore– CostlyCostly– DestructiveDestructive– Provides a good ground truth record.Provides a good ground truth record.

Falling Weight Deflectometer (FWD)Falling Weight Deflectometer (FWD)– None Destructive None Destructive

Ground Penetrating RadarGround Penetrating Radar– Non DestructiveNon Destructive– Collected at Highway SpeedCollected at Highway Speed– Dense CoverageDense Coverage– Heavy Post ProcessingHeavy Post Processing

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Related Work on Thickness EvaluationRelated Work on Thickness Evaluation

[Berge et al, 1986] initial pavement thickness studies[Berge et al, 1986] initial pavement thickness studies [Livneh and Siddiqui, 1992] mathematical model [Livneh and Siddiqui, 1992] mathematical model [Fernando, 2000; Scullion and Saarenketo, 2002] [Fernando, 2000; Scullion and Saarenketo, 2002]

automated interface identification automated interface identification [Al-Quadi et al, 2005] model expanded to three or more [Al-Quadi et al, 2005] model expanded to three or more

layerslayers SummarySummary There are multiple models available for pavement There are multiple models available for pavement

thickness evaluationthickness evaluation– The model selected for this study is utilized for a large The model selected for this study is utilized for a large

majority of the studiesmajority of the studies Current literature suggests using semi-automatic data Current literature suggests using semi-automatic data

interpretation methodologiesinterpretation methodologies

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FundamentalsFundamentals

GPR trace and waveforms and data GPR trace and waveforms and data presentationspresentations

Mathematical modelMathematical model

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Trace Example SR - 9

0

500

1000

1500

2000

2500

3000

0 20 40 60 80 100 120 140 160

Am

pli

tud

e0 1 2 3 4 5 6 7

Travel Time (nanoseconds)

Reflected Pulse Waveforms

0

500

1000

1500

2000

2500

3000

0 20 40 60 80 100 120 140 160

Sample #

Am

pli

tud

e

0 1 2 3 4 5 6 7

Radar pulse w aveform reflected off third interface

Positive phase wavefoms

Negative phase waveform

Starting State

SecondState

EndingState

Pulse Center

StartingState

Ending State

SecondState

Pulse Center

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GPR Data B-scanGPR Data B-scan

Amplitude

500

1000

1500

2000

2500

3000

3500

Distance (feet)

Tim

e (N

anos

econ

ds)

Data: i65n160.yat

0 1000 2000 3000 4000 5000

2

4

6

8

10

12

14

16

18

Interface 1 Interface 2

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Page 12: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

8967

29

3.9162.948

1.276

0

500

1000

1500

2000

2500

3000

3500

0 20 40 60 80 100 120

Am

plit

ud

e

0 1 2 3 4 5

Time (nanoseconds)

Two way travel time in first layer

Two way travel time in second layer

1

2 3

3293

582

1337

1724

0

500

1000

1500

2000

2500

3000

3500

0 20 40 60 80 100 120

Sample #

Am

plit

ud

e

0 1 2 3 4 5

Radar pulse w aveform reflected off pavement surface

Radar pulse w aveform reflected off f irst

pavement boundary

Radar pulse w aveform reflected off second pavement boundary

Amplitude of surface return, A0

Amplitude of return off first boundary A1

*A0

*

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EM Wave Propagation VelocityEM Wave Propagation Velocity

11.8/ sec m

R R

cV in nano

20

1 20

( )

( )p

Rp

A A

A A

0

R1

speed of light

Amplitude of Return off Metal Plate

Amplitude of Surface Return

Dielectric Constant Uppermost Surface Course

p

c

A

A

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Principles of GPR Interface Principles of GPR Interface InterpretationInterpretation

An interface is defined as the anomaly in GPR data An interface is defined as the anomaly in GPR data occurring when the reflected waveforms from a occurring when the reflected waveforms from a physical pavement boundary are contiguous for a physical pavement boundary are contiguous for a group of sequential tracesgroup of sequential traces

The radar (EM) wave must propagate, to the The radar (EM) wave must propagate, to the interface and back.interface and back.

The radar wave must reflect off the interface with The radar wave must reflect off the interface with enough energy to be recorded.enough energy to be recorded.

The interface must be identified in the GPR The interface must be identified in the GPR record.record.

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The source of the first interface isclassified as an HMA surface course

boundary

Do while currentinterface is HMA

Can the interface source beclassified as steel reienforcment

ClassifySource as

HMA surfacecourse

AnotherInterface ?

end

Classify sourceas steel

reineforcement

Anotherinterface ??

Do while currentinterface is steelreienforcement

end

Can the interface source beclassified as steel reienforcment

Classifysource as

steelreinforcement

Anotherinterface ??

Classifysource as

base of PCCboundary or

disregard

end

end

no

no

yes

yes

yes

no

no

no

Next interfaceclassify source as

HMA surfacecourse boundary

yes

Next interfaceclassify source as

steelreinforcement

yes

Classify source of secondinterface as an HMA surface

course boundary

The source of the first interfaceis steel reineforcement

Classify source of secondinterface as steel reinforcement

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Two Interface Case ATwo Interface Case A

Amplitude

500

1000

1500

2000

2500

3000

3500

RP(Miles)

Tw

o-W

ay T

rave

l Tim

e (N

anos

econ

ds)

I-74 Validation Section C

11.5 12 12.5 13 13.5 14 14.5 15 15.5

2

4

6

8

10

12

14

16

18

base of HMA steel reinforcement

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Two Interface Case BTwo Interface Case B

Amplitude

500

1000

1500

2000

2500

3000

3500

RP(Miles)

Tw

o-W

ay T

rave

l Tim

e (N

anos

econ

ds)

I-65 Validation Section North Bound

150 155 160

2

4

6

8

10

12

14

16

18

HMA interfaces

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Methodologies for Thickness Methodologies for Thickness Evaluation (regional M1)Evaluation (regional M1)

Top layer methodologyTop layer methodology– Discontinuities are located in dataDiscontinuities are located in data– Interfaces are identified in the dataInterfaces are identified in the data– Regional dielectric constants are determined Regional dielectric constants are determined – Thickness values are calculated for each mileThickness values are calculated for each mile– Enhanced to calculate thickness using dielectric Enhanced to calculate thickness using dielectric

constants from individual tracesconstants from individual traces

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Interface SelectionInterface Selection

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Regional Dielectric ConstantsRegional Dielectric Constants

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Thickness CalculationThickness Calculation

Every thickness pick is Every thickness pick is assigned the assigned the respective regional respective regional dielectric value.dielectric value.

Thickness Values Thickness Values Calculated.Calculated.

Average value Average value calculated for each calculated for each mile.mile.

Dielectric Regional

DielectricPick

ThicknessPick

Thickness Calculated

r

p

p

n

r

ppn

ε

tk

tk

tktk

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Multiple Layer Methodology (M2)Multiple Layer Methodology (M2)

Determine the layers to be modeledDetermine the layers to be modeled Form data set of possible interfacesForm data set of possible interfaces Select interfaces to be modeledSelect interfaces to be modeled Calculate thickness valuesCalculate thickness values Present the thicknesses in a visually acute Present the thicknesses in a visually acute

format allowing for proper interpretationformat allowing for proper interpretation

Page 23: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.
Page 24: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Quality of GPR DataQuality of GPR Data

BlundersBlunders– Improper waveform selectionImproper waveform selection– Omitted pavement layersOmitted pavement layers

Systematic errorsSystematic errors– Travel time systematic errorTravel time systematic error– Velocity systematic errorVelocity systematic error

Random errorsRandom errors– Error propagationError propagation

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Improper Waveform Improper Waveform Selection Selection

I-65 Study AreaI-65 Study Area13 Inches HMA Over PCC13 Inches HMA Over PCC

Amplitude

500

1000

1500

2000

2500

3000

3500

RP(Miles)

Tw

o-W

ay T

rave

l Tim

e (N

anos

econ

ds)

Data: I65 North Bound Transition 2

223.2 223.25 223.3 223.35 223.4 223.45

2

4

6

8

10

12

14

16

18

PCC overlay HMA overlay

HMA interfaces

before transition after transition

Amplitude

1350

1400

1450

1500

1550

1600

223.4 223.42 223.44 223.46 223.48

4

5

6

7

8

9

10

11

RP (miles)

Tw

o-W

ay T

rave

l Tim

e (N

anos

econ

ds)

Data: e86b005.yat

Base of HMA

Base of HMA lifts

after transition

330 mm (13 inches) of HMA overlay over rubblized JRCP

305 mm (12 inches) of concrete overlay over JRCP

190 mm (7.5 inches) of fiber modified HMA overlay over Cracked and Seated JRCP

MM 229.1

MM 223.4

MM 217.2

SB NB North to Chicago

MM 237.8

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Interface SelectionInterface Selection

0 200 400

4

4.5

5

5.5

6

6.5

7

7.5

8

8.5

9

Time: b006b.PKS

Distance (feet)

Tra

vel T

ime

(nan

osec

onds

)

HMA prior to transition 1

0 500 1000

4

4.5

5

5.5

6

6.5

7

7.5

8

8.5

9

Time: b005b.PKS

Distance (feet)

HMA following transition 2

0 500 1000

4

4.5

5

5.5

6

6.5

7

7.5

8

8.5

9

Time: b002b.PKS

Distance (feet)

HMA prior to transistion 3

(a) (b) (c)

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Positive Phase

0

500

1000

1500

2000

2500

3000

3500

4000

0 100 200 300 400 500

Am

pli

tud

e0 2 4 6 8 10 12 14 16 18

Time (nanoseconds)

N O P

Negative Phase (Twisted Trace)-1000

-500

0

500

1000

1500

2000

2500

3000

0 100 200 300 400 500

Am

pli

tud

e

0 2 4 6 8 10 12 14 16 18

Time (nanoseconds)

S

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Difference in Dielectric Constant and Difference in Dielectric Constant and ThicknessThickness

0 200 400 6004

4.5

5

5.5

6

6.5

7

7.5

8

8.5

9 Dielectric Constant of PCC for Positive and Negative Waveforms

Distance (feet)

Die

letr

ic C

onst

ant

PCC dielectric constantpositive phase waveform

0 200 400 6004

4.5

5

5.5

6

6.5

7

7.5

8

8.5

9

Distance (feet)

Die

lect

ric C

onst

ant

PCC dielectric constantnegative phase waveform

(a) (b) 0 200 400 600

9.5

10

10.5

11

11.5

12

12.5

13

13.5

14

14.5

HMA Overlay Thickness Positive and Negative Phase Waveforms

Distance (feet)T

hick

ness

(in

ches

)

HMA overlay thickness positive phase waveform

0 200 400 600

9.5

10

10.5

11

11.5

12

12.5

13

13.5

14

14.5

Distance (feet)

Thi

ckne

ss (

inch

es)

HMA overlay thickness negative phase waveform

(a) (b)

Positive PhaseDielectric constant

Negative PhaseDielectric Constant

Positive PhaseThickness

Negative PhaseThickness

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Error Omitted Pavement LayersError Omitted Pavement Layers

Amplitude

1350

1400

1450

1500

1550

1600

223.4 223.42 223.44 223.46 223.48

4

5

6

7

8

9

10

11

RP (miles)

Tw

o-W

ay T

rave

l Tim

e (N

anos

econ

ds)

Data: e86b005.yat

Base of HMA

Base of HMA lifts

after transition

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Omitted Pavement LayersOmitted Pavement Layers

0 200 400 600

11

11.5

12

12.5

13

13.5

14

14.5

15

HMA Section 2 Thickness Utilizing All Interfaces and Omitting Intermidiate Interfaces

Distance (feet)

Thi

ckne

ss (

inch

es)

HMA overlay thicknessomitting interfaces

0 200 400 600

11

11.5

12

12.5

13

13.5

14

14.5

15

Distance (feet)

Thi

ckne

ss (

inch

es)

HMA overlay thicknessall interfaces

(a) (b)

Thickness (Layers Omitted) Thickness (All Layers)

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Travel Time Systematic ErrorTravel Time Systematic Error

0 200 400 600 800 1000 1200-1500

-1000

-500

0

500

1000

1500

2000

2500Height 11 Inches

Sample #

Am

plitu

de

t1

t2 (a) 0 200 400 600 800 1000 1200

-1500

-1000

-500

0

500

1000

1500

2000

Sample #A

mpl

ititu

de

Example Hieght 22 inches

t1

t2 (b)

Page 32: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Time Scale Plot

y = 16.752x + 49.71

R2 = 0.9999

y = 17.4105x + 64.004

R2 = 0.9979

0

100

200

300

400

500

600

700

800

0 5 10 15 20 25 30 35 40

Antenna Height (inches)

Dif

fere

nce

in

Sam

ple

s

Channel 2

Channel 1

Linear (Channel 2)

Linear (Channel 1)

Channel 1RMS=4.77

Channel 2RMS=0.99

Width of Waveform

60

70

80

90

100

110

120

130

0 5 10 15 20 25 30 35 40

Antenna Height (inches)

Wav

efo

rm W

idth

(sa

mp

les)

Channel 2 w idth

Channel 1 w idth

Channel 1Mean: 106.5STD: 12.45COV: 11.7%

Channel 2Mean: 86.5STD: 0.60COV 0.7 %

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Velocity Systematic ErrorVelocity Systematic Error

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Random Error Random Error

0

0 0

0

2 2 2

02 2 202 2 2

0 0 0

2 2 2 2 2 2 2 20 02 2 2

0 0

2 2 2 202 2

0

22

2 2

( )

2relative error

p

p p

p

ppD A A t

p p p

D A p A D A p Ap p

DA p A

p

A AtAtAc

A A A A A A

ct DA A A A

A A A A

A AD A A

0

D

0

2 2

Standard deviation thickness, Relative error, Speed of light

Metal plate amplitude, Surface return amplitude, Thickness

Variance surface return amplitude, Variance metal platp

D

p

A A

cD

A A D

2

e amplitude,

Travel time, Variance trave timett

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Error SummaryError Summary

Improperly selecting waveforms is a significant Improperly selecting waveforms is a significant blunder sourceblunder source

Utilizing automated interface selection algorithm Utilizing automated interface selection algorithm increased the likelihood of this blunderincreased the likelihood of this blunder

Omitting pavement layers introduces errorsOmitting pavement layers introduces errors Channel 1 data not used due to large systematic error Channel 1 data not used due to large systematic error

is travel timeis travel time Velocity systematic errors propagate into thickness Velocity systematic errors propagate into thickness

errorerror Amplitude random error propagates to about 1% Amplitude random error propagates to about 1%

relative thickness error relative thickness error

Page 36: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Validation of MethodologiesValidation of Methodologies

Comparison with 3Comparison with 3rdrd party Software party Software Comparison of methodologies developedComparison of methodologies developed Thickness variationThickness variation Network thickness studyNetwork thickness study GPR thickness evaluation accuracyGPR thickness evaluation accuracy

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Thickness ComparisonsThickness Comparisons

Seven pavement sections of three Seven pavement sections of three interstates. interstates.

Pavement sections of three state roadsPavement sections of three state roads Five pavement sections of two interstates Five pavement sections of two interstates

used for 3used for 3rdrd party comparison party comparison

Page 38: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Statistical Analysis (M2 vs TERRA)Statistical Analysis (M2 vs TERRA)

Population IntersectionPopulation Intersection Split into 50 or 25 foot subsectionsSplit into 50 or 25 foot subsections Normality, F test, and T-test analysisNormality, F test, and T-test analysis Explanation of T-test resultsExplanation of T-test results

Page 39: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Normality Analysis of Sub Section Populations

H0=Population Normally Distributed

Alpha=95%

Thickness Normality Analysis

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

I65 (50 ft) I74A (50ft) I74A (25ft) I74B (50ft) I74B (25ft) I74C (50ft) I74C (25ft) I74F (50ft) I74F (25ft)

Per

cen

tag

e F

aile

d N

orm

alit

y G

oo

dn

ess

of

Fit

Tes

t M2 Omni

M2 JB

M2 Lillifors

TERRA Omni

TERRA JB

TERRA Lillifors

Page 40: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Equality of Means and VarianceAnalysis of Sub Section PopulationsH0=Populations Have Same VarianceAlpha=95%H0=Populations Have Same MeansAlpha=99%

Thickness Equality of Means and Variance Test Results

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I65 (50 ft) I74A (50ft) I74A (25ft) I74B (50ft) I74B (25ft) I74C (50ft) I74C (25ft) I74F (50ft) I74F (25ft)

Per

cen

tag

e W

her

e N

ull

Hyp

oth

esis

Rej

ecte

d

F-test

T-pooled variance

T-unequal variance

Page 41: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

14.2

4.4

4.6

4.8

Val

ues

Column Number

-2 -1.5 -1 -0.5 0 0.5 1 1.5 24

4.2

4.4

4.6

4.8

5

Standard Normal Quantiles

Qua

ntile

s of

Inp

ut S

ampl

e

QQ Plot of Sample Data versus Standard Normal

14.2

4.4

4.6

4.8

Val

ues

Column Number

-2 -1.5 -1 -0.5 0 0.5 1 1.5 24

4.2

4.4

4.6

4.8

5

Standard Normal Quantiles

Qua

ntile

s of

Inp

ut S

ampl

e

QQ Plot of Sample Data versus Standard Normal

(a)

(d)

(c)

(b)1

4.8

5

5.2

5.4

Val

ues

Column Number

-1.5 -1 -0.5 0 0.5 1 1.54.5

5

5.5

Standard Normal Quantiles

Qua

ntile

s of

Inp

ut S

ampl

e

QQ Plot of Sample Data versus Standard Normal

14.8

5

5.2

5.4

Val

ues

Column Number

-1.5 -1 -0.5 0 0.5 1 1.54.5

5

5.5

Standard Normal Quantiles

Qua

ntile

s of

Inp

ut S

ampl

e

QQ Plot of Sample Data versus Standard Normal

(a)

(d)

(c)

(b)

Best Case Worst CaseI-65 T-test 8% Rejected

Page 42: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

1

5.8

6

6.2

6.4

6.6

Val

ues

Column Number

-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.55

5.5

6

6.5

7

Standard Normal Quantiles

Qua

ntile

s of

Inp

ut S

ampl

e

QQ Plot of Sample Data versus Standard Normal

1

5.8

6

6.2

6.4

6.6

Val

ues

Column Number

-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.55.5

6

6.5

Standard Normal Quantiles

Qua

ntile

s of

Inp

ut S

ampl

e

QQ Plot of Sample Data versus Standard Normal

(d)

(c)

(b)(a)

1

7.7

7.8

7.9

8

8.1

8.2

Val

ues

Column Number

-1.5 -1 -0.5 0 0.5 1 1.57.5

8

8.5

Standard Normal Quantiles

Qua

ntile

s of

Inp

ut S

ampl

e

QQ Plot of Sample Data versus Standard Normal

1

7.7

7.8

7.9

8

8.1

8.2

Val

ues

Column Number

-1.5 -1 -0.5 0 0.5 1 1.57.5

8

8.5

Standard Normal Quantiles

Qua

ntile

s of

Inp

ut S

ampl

e

QQ Plot of Sample Data versus Standard Normal

(d)

(c)

(b)(a)

Best Case Worst Case

I-74F T-test 72% Rejected

Page 43: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.
Page 44: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

T-test ExplanationT-test Explanation

15 20 25 30 35 40 45 500

500

1000

1500

2000

2500

3000

3500

4000

I-74 Validation Section A Trace Group A

Sample #

Am

plitu

de

Amplitude M2 Amplitude TERRA

Difference

Page 45: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Summary M2 TERRA ComparisonSummary M2 TERRA Comparison

90% of the M2 and TERRA populations 90% of the M2 and TERRA populations have the same variance (alpha=95%)have the same variance (alpha=95%)

98% of the M2 and TERRA populations for 98% of the M2 and TERRA populations for I-65 have the same mean (alpha=99%)I-65 have the same mean (alpha=99%)

28% of the M2 and TERRA populations for 28% of the M2 and TERRA populations for I-74F have the same mean I-74F have the same mean

Page 46: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Methodology ComparisonsMethodology Comparisons

Effect of sample sizeEffect of sample size Effect of using regional dielectric constantEffect of using regional dielectric constant

Page 47: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Difference in Thicknesses (M2 - traces M1)

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 10 20 30 40 50 60 70 80

Thi

ckne

ss D

iffe

renc

e (i

nche

s)

I-65

I-74

SR-28

SR-47

SR-213

standard deviation

M2

I-69

Page 48: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Difference in Thickness Values (traces M1 - regional M1)

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

0 10 20 30 40 50 60 70 80

Sample #

Th

ickn

ess

Dif

fere

nce

(in

ches

)

I-65

I-69

I-74

SR-28

SR-47

SR-213

standard deviation

traces M1

Page 49: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Network Thickness EvaluationOver 1,600 Miles EvaluatedUppermost Surface Course Thickness Evaluated with GPR Using Regional M1 MethodPavement Structure Thickness Evaluated with FWD

I - 65 South Bound Driving Lane

0

5

10

15

20

25

30

35

40

0 20 40 60 80 100 120 140 160 180 200 220 240 260

Reference Post, Miles

Pav

emen

t T

hic

knes

s, I

nch

es

GPR, Surface Course 1 Thickness GPR, Thickness to 2nd Interface

FWD, Surface Thickness FWD, Total Thickness

Page 50: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Network Thickness EvaluationNetwork Thickness Evaluation

A majority of the INDOT interstate system is A majority of the INDOT interstate system is 25 inches thick with an uppermost surface 25 inches thick with an uppermost surface course thickness of 5 to 7 inches of HMA.course thickness of 5 to 7 inches of HMA.

GPR provided reasonable estimates of the GPR provided reasonable estimates of the uppermost surface course thicknessuppermost surface course thickness

FWD provided reasonable estimates of the FWD provided reasonable estimates of the pavement structure thicknesspavement structure thickness

Page 51: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Thickness VariationThickness Variation

SectionSection NumberNumber MeanMean STDSTD CVCV

I-65I-65 25,67225,672 4.624.62 0.440.44 9.45%9.45%

I-69I-69 41,10841,108 6.486.48 0.570.57 8.72%8.72%

I-74AI-74A 16,58716,587 6.676.67 0.540.54 8.10%8.10%

I-74BI-74B 8,8108,810 3.743.74 0.400.40 10.67%10.67%

I-74CI-74C 15,70415,704 4.974.97 0.340.34 6.93%6.93%

I-74DI-74D 14,25014,250 7.277.27 0.580.58 7.94%7.94%

I-74FI-74F 21,42721,427 6.906.90 0.540.54 7.81%7.81%

SR-47SR-47 32,26032,260 5.705.70 0.390.39 6.78%6.78%

SR-213SR-213 6,2336,233 6.186.18 0.470.47 7.65%7.65%

SR-28SR-28 20,67020,670 6.666.66 1.361.36 20.49%20.49%

AverageAverage 9.45%9.45%

Average*Average* 8.23%8.23%

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Published CV valuesPublished CV values

StudyStudy CVCV

LTPP HMALTPP HMA 6.83% to 12.66%6.83% to 12.66%

LTPP PCCLTPP PCC 2.36% to 5.19%2.36% to 5.19%

NCDOT HMANCDOT HMA 25% to 38%25% to 38%

Page 53: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Reported Accuracies of GPR Reported Accuracies of GPR Thickness EstimatesThickness Estimates

REPORTREPORT AccuracyAccuracy

Kansas DOT Kansas DOT 7.5% - 10%7.5% - 10%

SHRPSHRP 8%8%

Minnesota DOTMinnesota DOT 3% - 6.5%3% - 6.5%

Missouri DOTMissouri DOT 4% - 11.3% 4% - 11.3%

Kentucky DOTKentucky DOT 5.82% - 165.04%5.82% - 165.04%

Page 54: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Case Study ResultsCase Study Results

StudyStudy AccuracyAccuracy

I-65I-65

12 Inch Concrete12 Inch Concrete 4.5%4.5%

13 Inch HMA13 Inch HMA 2.0%2.0%

7.5 Inch HMA7.5 Inch HMA 13.2%13.2%

US41 NorthUS41 North

HMAHMA 8.8%, 5.2%8.8%, 5.2%

Concrete Concrete 8.8%8.8%

SR32ESR32E

HMAHMA 16.6%16.6%

Page 55: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Accuracy/CV ResultsAccuracy/CV Results

Study CV (8.23%) within published range of Study CV (8.23%) within published range of 2.36% to 38%2.36% to 38%

Study absolute accuracy range (2% to Study absolute accuracy range (2% to 16.6%) in within published range of 3% to 16.6%) in within published range of 3% to 23.4%23.4%

Page 56: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

ConclusionsConclusions

M1 provides efficient acceptable M1 provides efficient acceptable thicknesses for the uppermost pavement thicknesses for the uppermost pavement surface coursesurface course

M2 provides accurate pavement M2 provides accurate pavement thicknesses for multilayer pavementsthicknesses for multilayer pavements

The expanded visualization tools of M2 help The expanded visualization tools of M2 help prevent interface interpretation blundersprevent interface interpretation blunders

Page 57: Pavement Thickness Evaluation Using Ground Penetrating Radar Dwayne Harris Dwayne Harris Presented for Final Exam.

Conclusions ContinuedConclusions Continued

Likelihood of interface interpretation blunders Likelihood of interface interpretation blunders increases when automated interface selection increases when automated interface selection and tracking algorithmand tracking algorithm

The process of evaluating pavement thickness The process of evaluating pavement thickness with GPR has not progressed to the point of with GPR has not progressed to the point of eliminating a trained GPR interpretereliminating a trained GPR interpreter

Study absolute accuracy range (2% to 16.6%) Study absolute accuracy range (2% to 16.6%) within published range of 3% to 23.4%within published range of 3% to 23.4%