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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
3
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!
4
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
5
Surface Condition Survey (Windshield Survey)
Overall subjective assessment
Segments of variable condition may not be apparent
6
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?
7
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
9
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
11
DSV Survey Systems
Right of Way Camera System
DMI
DGPS INS
Pavement Imaging Pavement Imaging System
DGPS INS
Pavement Illumination System
ROW Cameras
12
I-95 DSV Condition Survey
High resolution downward pavement images viewed with customized software
13
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
14
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
18
Sampling of Forward Images
19
20
21
22
23
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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
25
Distress Quantity & Severity Summary
26
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
27
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
29
2nd Example: PennDOT I-81 (Lebanon County)
Simpler investigation
Thin HMA overlay covering concrete
Survey focus- joints & patches
Used DSV to collect data safely
30
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
31
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)
32
That’s it for the DSV & Condition Surveys
33
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
34
Subsurface Pavement Investigation Destructive Testing
Conventional cores & borings
Cone Penetrometer Testing (CPT)
35
Subsurface Investigation Non-Destructive Testing
Falling Weight Deflectometer (FWD) Structural evaluation
Ground Penetrating Radar (GPR) Layer thickness Other applications
36
Falling Weight Deflectometer (FWD)
37
FWD Schematic
Weight dropped on load plate
Deflection measured at series of sensors
38
• 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
39
SC
Section 1 Section
2
Distance
Average Structural Capacity
40
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
41
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
42
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
43
• Evaluate efficiency of load transfer across joint or crack
• Useful data for evaluating feasible rehab treatments
Joint Load Transfer Evaluation
44
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)
45
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
46
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
47
Ground Penetrating Radar
Aerial Antennas Ground Coupled Antennas
(portable unit)
48
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
49
GPR – Granular Thickness
50
Concealed Repair Patches
51
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)
52
MIT Scan-T (Pavement Thickness)
53
MIT Scan- Dowel Bar Alignment
Construction Acceptance Testing Often required if automated dowel bar inserter
Forensic Evaluations:
54
Other Unique Tools
Cover if time permits
55
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
56
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
57
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
58
Equipment on Display
Digital Survey Van
Falling Weight Deflectometer
Check out equipment on your way out…..
59
QUESTIONS???