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Goals of Presentation

Describe tools & techniques for pavement evaluation

Help highway designers select appropriate ones

Surface Evaluation Conventional approaches Innovative approaches

Subsurface Evaluation Destructive – conventional cores & borings Non-Destructive- deflection testing, ground penetrating radar, other

specialized tools

Tools and Techniques

for Pavement Evaluation

Paul Wilke, P.E.

ASHE Harrisburg Section Meeting

March, 2012

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Goals of Pavement Evaluation

Quantify pavement conditions and uniformity/variability

Identify causes of distresses

Estimate remaining pavement life

Provide parameters needed to identify (and design) feasible rehab alternatives

Should only collect data that will be used for decision making!

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Components of Pavement Investigation

Surface conditions Evaluation of visible distresses Evaluation of other features (roughness, skid resistance)

Subsurface conditions Pavement composition & thickness Condition of pavement layers Soil types and strength

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Surface Condition Survey (Windshield Survey)

Overall subjective assessment

Segments of variable condition may not be apparent

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Surface Condition Survey (Detailed Distress Mapping)

Most useful when detailing specific “spot repairs” Eg- Concrete pavement restoration Dowel bar retrofits, full depth patches, etc

Can be “information overload” How will you make rehab decisions from the distress map?

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Surface Condition Survey Pavement Condition Index (PCI) Approach

Intermediate between 2 extremes

Useful in identifying segments of variable condition Developing more than rehab treatment

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Condition Survey (PCI Approach)

Project divided into sections (segments) Consider pavement history Typically uniform segment lengths

Type, quantity & severity of distresses measured (or estimated) Can be used for repair quantities

Calculation of overall condition index can be useful Helps identify variability between segments

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Options for PCI- Type Surveys

Foot on ground (FOG)survey

Semi-automated -Digital Survey Vehicle (DSV) Automated collection of high resolution downward facing pavement images Manual distress rating in office

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Digital Survey Vehicle

Data Collected – Digital Video Pavement

Images – Multiple Digital Video

Right-of-Way Images – Longitudinal

Profile/Roughness – Rutting – Faulting – Cross-slope & Grade – Macro-Texture – Linear Distance – GPS Coordinates

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DSV Survey Systems

Right of Way Camera System

DMI

DGPS INS

Pavement Imaging Pavement Imaging System

DGPS INS

Pavement Illumination System

ROW Cameras

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I-95 DSV Condition Survey

High resolution downward pavement images viewed with customized software

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Comparison of Condition Survey Methods

DSV vs FOG Methods

Similar end result

DSV faster & safer for field data collection

DSV typically more accurate (unless physical measurements made with FOG)

DSV provides geo-referenced images for other uses

DSV provides roughness, rutting, faulting & cross-slope measurements

FOG costs less for small projects with low traffic volume

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Example of Condition Survey Data & Uses (I-95 New England Thruway)

84 lane-miles; 140,000 AADT; 12% trucks

Two different pavement design sections

Variable pavement conditions

Two phase project Preliminary design- pavement investigation; identify rehab treatment(s) and

cost Final Design- contract documents (including detailed repair plan & details)

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High Traffic Volume Precluded FOG Survey DSV Survey Performed

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Example Distress Rating

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Forward Images Provided

Right of Way Cameras not used for collection of roadside assets

Very useful to transportation design firm

Specialized software not required to view images

Southbound MP 4.372

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Sampling of Forward Images

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21

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I-95 Pavement Data

Phase I complete: Summarized data multiple ways to aid in evaluations by segment

More than one rehab treatment identified

Repairs types & quantity assigned by distress type & severity

Used for quantities in preliminary costs

Phase II underway:

Detailed repair maps for concrete pavement repairs

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Distress Quantity & Severity Summary

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IRI (0.1 mile averages)

0

50

100

150

200

250

300

350

0

0.3

0.6

0.9

1.2

1.5

1.8

2

2.3

2.6

2.9

3.2

3.5

3.8

4.1

4.4

4.7

5

5.3

5.6

5.9

6.2

6.5

6.8

7.1

7.4

7.7

8

8.3

8.6

8.9

9.2

9.5

9.8

10

.1

10

.4

10

.7

11

11

.2

11

.5

11

.8

12

.1

12

.4

12

.7

13

13

.3

13

.6

13

.9

14

.1

14

.4

14

.7

NB Left Lane- Average IRI

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Average PCI by Segment

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CONDITION INDEX (PCI) SUMMARY Condition Condition

Category Left Center Right Category Left Center Right

A 0.17-1.00 26 40' 69 60 55 A 0.17-1.00 26 40' 59 48 47

A 1.00-2.00 26 40' 68 59 59 B 1.00-2.00 27 40' 76 61 63

A 2.00-2.33 26 40' 75 62 58 B 2.00-3.00 * 40' 75 63 69

B 2.33-2.55 19 AC 88 88 89

A 2.55-3.00 27 40' 63 49 55

A 3.00-4.00 21 40' 65 49 56 C 3.00-4.00 21 40' 68 46 55

A 4.00-5.00 21 40' 64 56 56 C 4.00-5.00 21 40' 61 58 57

A 5.00-6.00 21 40' 72 55 70 D 5.00-6.00 21 40' 67 69 74

A 6.00-6.72 24 40' 61 60 62 C 6.00-7.00 24 40' 71 63 56

Toll Plaza E 7.00-7.20 22 40' 70 32 46

C 7.10-8.00 16 18' 92 95 98 F 7.20-8.00 16 18' 93 89 92

C 8.00-8.8 16 18' 91 93 97 F 8.00-8.72 16 18' 98 84 90

A 8.80-9.41 21 40' 72 64 54 G 8.72-10.02 ? AC 93 86 70

B 9.41-10.00 ? AC 91 84 84

A 10.00-10.80 21 40' 72 65 65 / 83 C 10.02-10.86 21 40' 68 59 58

C 10.80-12.00 17 18' 95 95 94 F 10.86-12.00 17 18' 89 88 95

C 12.00-13.00 17 18' 96 91 94 F 12.00-13.15 17 18' 92 83 86

D 13.00-14.03 19 40' 77 75 69 D 13.15-14.03 19 40' 74 64 70

E 14.03-14.07 19 AC 60 20 46 H 14.03-14.07 19 AC 44 56 53

Avg PCI Avg PCI

Overall 76.2 67.8 70.6 Overall 74.9 65.6 67.6

PCC (40' Jts) 68.9 59.5 60.7 PCC (40' Jts) 68.9 56.3 59.5

PCC (18' Jts) 93.5 93.3 95.8 PCC (18' Jts) 93 86 90.8

AC Overlay PCI ≥ 71 Good/Satisfactory * age 27 except 2.50-2.85= 19 yrs

Fair

18' Joints PCI ≤ 55 Poor

56 ≤ PCI ≤ 70

SouthboundNorthbound

Table 1 – Pavement Condition Index (PCI) Summary

Pvmt

Age

Joint

SpacingMP Range

Pvmt

Age Joint Spacing

PCIMP Range

PCI

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2nd Example: PennDOT I-81 (Lebanon County)

Simpler investigation

Thin HMA overlay covering concrete

Survey focus- joints & patches

Used DSV to collect data safely

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Distress Quantity Summary

Low Moderate High Low Moderate High Low Moderate High

96.7 To 97.0 Longitudinal Cracking LC - - - - 398.6 - - 21.0 -

Transverse Cracking TC - - - - 96.0 - - 8.0 -

Patching (LJ) Patch - LJ - - - - - - - - -

Patching (TJ) Patch - TJ - - - - - - - - -

Patching (Other) Patch -O - - - - - - - - -

97.0 To 97.5 Longitudinal Cracking LC - - - - 2,513.1 57.5 - 160.0 14.0

Transverse Cracking TC - - - - 504.0 72.0 - 42.0 6.0

Patching (LJ) Patch - LJ 3.1 59.3 - - - - 2.0 15.0 -

Patching (TJ) Patch - TJ 2.1 12.7 - - - - 1.0 3.0 -

Patching (Other) Patch -O - - - - - - - - -

97.5 To 98.0 Longitudinal Cracking LC - - - - 2,286.9 14.1 - 146.0 2.0

Transverse Cracking TC - - - - 504.0 48.0 - 42.0 4.0

Patching (LJ) Patch - LJ 3.4 16.4 7.8 - - - 1.0 9.0 3.0

Patching (TJ) Patch - TJ - 9.2 3.1 - - - - 3.0 1.0

Patching (Other) Patch -O - - - - - - - - -

I- 81 Southbound Passing Lane

Mile Post DistressDistress

Code

Area Length Count

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Comparison of Condition Surveys (I-95 & I-81)

Not all projects require same level of detail

PCI very useful for I-95 in identifying segments of similar condition

PCI would not have been useful for I-81

Not necessary to quantify all distresses for I-81

Windshield survey would have had signficant limitations for I-95 or I-81 (more quantitative data helped decision making)

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That’s it for the DSV & Condition Surveys

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Skid Resistance (Friction)

Locked Wheel Skid Resistance Testing (ASTM E-274)

Smooth (ASTM E-524) and/or Ribbed (ASTM E-501) Test Tire

Measures friction under flooded conditions

Tests performed at 40 MPH

Data reported as SN or FN

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Subsurface Pavement Investigation Destructive Testing

Conventional cores & borings

Cone Penetrometer Testing (CPT)

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Subsurface Investigation Non-Destructive Testing

Falling Weight Deflectometer (FWD) Structural evaluation

Ground Penetrating Radar (GPR) Layer thickness Other applications

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Falling Weight Deflectometer (FWD)

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FWD Schematic

Weight dropped on load plate

Deflection measured at series of sensors

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• Evaluate variability of overall pavement strength

• Determine “strategic” core & boring locations

• Determine subgrade soil strength

• Structural adequacy & remaining life

• Provides parameters for overlay design

• Void location (concrete pavements)

• Joint load transfer (concrete pavements)

Uses of FWD

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SC

Section 1 Section

2

Distance

Average Structural Capacity

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Example FWD Test Results

Maximum Deflection Normalized to 9000 and 70 ºF

Lane 1 Lane 2 Lane 3 Lane 1 Lane 2

0

2

4

6

8

10

12

14

18

15.000 16.000 17.000 18.000 19.000 20.000 21.000 22.000 23.000 24.000 Station

Ma

xim

um

def

lect

ion

, in

x1

0-3

d

0

50

100

150

200

250

300

350

400

Ma

xim

um

deflectio

n, µ

m

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1-41

Example FWD Test Results

Subgrade Resilient Modulus

15.000 16.000 17.000 18.000 19.000 20.000 21.000 22.000 23.000 24.000

Station

0

7500

15000

22500

30000

Res

ilie

nt

mo

du

lus,

psi

Lane 1 Lane 2 Lane 3 Lane 1 Lane 2

0

50

100

150

200

Resilien

t mo

du

lus, M

Pa

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Example FWD Test Results

Effective Structural Number

Lane 1 Lane 2 Lane 3 Lane 1 Lane 2

0

4

8

12

16

20

15.000 16.000 17.000 18.000 19.000 20.000 21.000 22.000 23.000 24.000

Station

Str

uct

ura

l n

um

ber

, in

0

10

20

30

40

50

Stru

ctura

l nu

mb

er, cm

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• Evaluate efficiency of load transfer across joint or crack

• Useful data for evaluating feasible rehab treatments

Joint Load Transfer Evaluation

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Deflection Testing Rigid Pavements

(loaded) (unloaded)

= 0 mm = 0.66 mm

0% Load transfer

100% Load transfer

= 0.33 mm = 0.33 mm

(loaded) (unloaded)

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FWD Load Transfer Efficiency (Sample Data)

Stations

(Miles)D1 D3 D9

Joint Efficiency

Approach Side %

Joint Efficiency

Leave Side

%

Pass/Fail

5.61 2.03 3.74 36.19

5.22 2.02 3.69 38.70

9.10 3.62 6.30 39.789.02 3.63 6.28 40.24

3.48 2.77 2.83 79.603.30 2.74 2.81 83.03

5.52 4.82 5.01 87.32

5.44 4.83 4.96 88.79

2.89 2.76 2.82 97.58

3.06 2.74 2.80 91.505.21 4.84 4.98 95.59

5.30 4.86 4.95 93.40

6.88 4.70 5.50 68.31

6.62 4.63 5.45 69.94

11.41 8.03 9.33 70.38

11.42 8.09 9.34 70.84

7.22 5.35 4.97 68.84

7.26 5.32 4.93 67.91

12.24 9.13 8.57 70.0212.33 9.13 8.60 69.75

96.845 FAIL

96.864 PASS

96.927 FAIL

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Combined Distress & FWD Data (To Estimate Patching)

SR-81 MP 96.7 to 104.0 FWD Pavement Total Lane % of Lane

Direction Lane TC (M) TC (H) Fail % Patching (SF) Area (SF) Patching

NB Travel 451 69 75 28,080 462,528 6.1%

SB Travel 619 54 79 38,280 462,528 8.3%

NB Passing 434 13 41 13,195 462,528 2.9%

SB Passing 479 68 71 27,963 462,528 6.0%

TOTAL 107,518 1,850,112 5.8%

TC(M) = Number of Moderate Severity Transverse Cracks rated from images.

TC(H) = Number of High Severity Transverse Cracks rated from images.

Pavt Patching (SF) = (TC(M) + TC(H)) x (FWD Fail%) x (6 x 12)

Total Lane Area (SF) = (104-96.7) x 5280 x 12

Summarized Estimated Pavement Patching Quantities

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Ground Penetrating Radar

Aerial Antennas Ground Coupled Antennas

(portable unit)

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Asphalt Thicknesses

0

50

100

150

200

250

300

350

18810 18910 19010 19110 19210 19310 19410 19510 19610 19710 19810

Dep

th (m

m)

Position (m)

Hwy 7 WB Lane 1 - Asphalt Thickness Station 18+810 to 19+810

GPR Asphalt Measurements Pavement Core Measurements

Determining areas of varying asphalt thickness

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GPR – Granular Thickness

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Concealed Repair Patches

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Magnetic Imaging Tools

Magnetic imaging tools emit and detect magnetic fields

Any metallic objects within proximity of the scan unit are identified and can be measured

Applications include: Measuring lift thickness (MIT Scan-T) Spatial location of dowel bars (MIT Scan 2)

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MIT Scan-T (Pavement Thickness)

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MIT Scan- Dowel Bar Alignment

Construction Acceptance Testing Often required if automated dowel bar inserter

Forensic Evaluations:

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Other Unique Tools

Cover if time permits

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Rolling Wheel Deflectometer

FWD concept applied to tractor trailer

Continuous deflection measured by laser

Less accurate (useful at network level)

Laser between dual tires

Reference beam and forward lasers

Applied Research Associates, Inc. Proprietary Information

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Rolling Weight Deflectometer

D1 C1 B1 A1

A2 B2 C2 D2

Deflection is difference between deflected and undeflected

surfaces (i.e., D2 – C1)

Distance = 8 ft

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Pavement Noise Measurement

OBJECTIVES:

Compare the noise characteristics of 5 HMA test sections Collect and analyze

sound intensity data as the in-service pavements age

SPONSOR: Illinois State Toll Highway Association (ISTHA)

DELIVERABLE: Engineering report summarizing relative and time dependant noise

characteristics of the five HMA test sections.

close-up of dual sound intensity probes.

Applied Research Associates, Inc. Proprietary Information

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Equipment on Display

Digital Survey Van

Falling Weight Deflectometer

Check out equipment on your way out…..

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QUESTIONS???