Rolling Wheel Deflectometer: Integrating Data in Pavement ...
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Rolling Wheel Deflectometer: Integrating Data in Pavement Management Rolling Wheel Deflectometer: Integrating Data in Pavement Management Presented by: Thomas Van, PE Presented by: Thomas Van, PE U.S. Department of Transportation Federal Highway Administration U.S. Department of Transportation Federal Highway Administration
Transcript of Rolling Wheel Deflectometer: Integrating Data in Pavement ...
Rolling Wheel Deflectometer: Integrating Data in Pavement Management
Rolling Wheel Deflectometer: Integrating Data in Pavement Management
Presented by:Thomas Van, PEPresented by:Thomas Van, PE
U.S. Department of TransportationFederal Highway AdministrationU.S. Department of TransportationFederal Highway Administration
Coming Up…Managing Pavements, Why DeflectionDeflection MeasurementsState of the PracticeCase StudySummary
Managing Pavements:Why Deflection?CrackingRuttingRide QualityMaterial Failures
Pavement Failures
Traffic
Managing Pavements:Why Deflection?
As an Indicator for Structure..When will it needs attention?Does Preservation make sense?Did we figure traffic correctly?Were there construction issues?
Measuring Deflection
LaboratoryField
Manual Methods:
Measuring Deflection
Benkelman Beam
Static Device Methods:
Photo of Benkelman Beam, FWD, LaCroix Device
Measuring Deflection
LaCroix Deflectograph
Static Device Methods:
Measuring Deflection
Falling Weight Deflectometer
Static Device Methods:
Measuring Deflection
DynaflectRoad Rater
Steady-State VibratoryMethods:
Measuring DeflectionDynamic Vibratory Device Methods:Texas Rolling Dynamic Deflection (RDD)
Measuring Deflection
Danish Traffic Speed DeflectometerSwedish Road Deflection TesterAmerican Rolling Wheel Deflectometer
High-Speed Device Methods:
The RWD• Measures the continuous
pavement deflection profile due to an 18-kip single axle truck load
• Provides a measure of the overall structural capacity of highway sections
• Information can be used for network-level evaluation and management
• Pre-screener for where to focus project-level efforts (i.e., FWD, coring, etc.)
RWD Benefits• Increased safety. Does
not require lane closures.• Mixes with traffic stream.
No interruption to traveling public.
• Operates over a broad range of speed (5 to 65 mph).
• High data collection productivity.
• Rapid data processing.
RWD Role in DOT OperationsNetwork-Level Project-Level
0
1
2
3
4
5
6
7
8
3+000 4+000 5+000 6+000 7+000 8+000 9+000 10+000Chainage
IRI,
m/k
m
Left WP Right WP
PSI
IRI
RWD
Potential^
FWD
Coring
Lab
10,0
00 la
ne-m
iles
Preservation
Rehabilitation or Reconstruction
100
lane
-mile
s
Indiana SR 1 – 3 Structures
0
20
40
60
80
Mile Marker
Deflection, mils
Good
65 70 75 80 85 90 95
Poor
Good
0
10
20
30
40
50 60 70 80 90 100 110 120 130 140 150
Deflection, mils
Mile Marker
Kansas – US 59
RWD
FWD
* Year of FWD Testing
CHAMPAIGN COUNTYRWD-BASED PMS IMPLEMENTATION
Background• Champaign County’s
network:– 400 lane-miles– Low-volume (farm-to-market)
roads– Asphalt-surfaced. Multiple
resurfacings– Variable surface, ride, and
structural conditions• Current highway budget is
approximately $2M per year
Key InputsRWDVideo imagesSmoothness dataConstruction historyTrafficCost data
County Road 32
0
10
20
30
40
50
60
0 2 4 6 8 10
Thin AC over a surface treatment -
High deflections
US
136
Giff
ord
AC over a cold millings base -
Strongest section
AC over a granular base - Good uniformity
RWDFWD
Mile Marker
Deflection, mils
Structural Conditions
0.6%
41.6%
15.1%15.1%
27.7%
0%
10%
20%
30%
40%
50%
< 10 10 to 20 20 to 35 35 to 50 > 50
Representative RWD deflection, mils
Perc
ent o
f mile
age
Pavement structural conditions vary widely
Excellent
Very Good
Good
Fair
Poor
Complete Treatment Matrix
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PCI PCI < 35 35 - 50 > 50 High TrafficValue Rating < 45 45 - 75 > 75 Low Traffic
Good Fair Poor Structural Rating
0
4-in AC Mill and Overlay Reconstruction
2-in AC Mill and Overlay
Defer Improvements
4-in AC Mill and Overlay
Chip seal, Microsurfacing
(maximum 2 times)
Representative RWD Deflection, mils
Defer Maintenance
Crack sealing (maximum 1 time)
Excellent
Poor
100
Very Good
Good
Fair
40
65
80
90
30
40
50
60
70
80
90
100
2006 2007 2008 2009 2010 2011
PCI
Unlimited $3M per year $2.5M per year
$2M per year $3M per year (No PM) $2.5M per year (No PM)
$2M per year (No PM) Do Nothing
Network Condition vs. Funding
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PMS Results• Produced a 5-year maintenance and
rehabilitation plan– Prioritized projects– Recommended treatments
• RWD helped identify the most appropriate treatment for each road– Pavement preservation– Functional improvement– Structural improvement
• 5-year budget analysis showed the consequences of various funding scenarios
SUMMARY
Conclusions
• It’s not just about Ride Quality!!• Cracking and Rutting are
important parameters.• Pavement Structure is too
important to ignore.• Don’t abandon the proven
methods.
Conclusions• RWD is an effective means of measuring
continuous pavement deflections and structurally characterizing pavement sections
• Accuracy and repeatability are suitable for network- and project-level evaluation
• Compares well to other references (i.e., FWD data)
• Can be used in PMS to optimize treatment selection, candidate projects, and funding allocation
Updates • RWD is now available for commercial
testing. ARA is the service provider.• Two pilot programs have been funded in
2008, anticipating more in 2009.• Focusing testing on states that are
interested in incorporating RWD data into their PMS activities
