Pavement Condition Survey Evaluation, Lecture 6
Pavement Condition Survey Evaluation, Lecture 6
Pavement Condition Survey Evaluation, Lecture 6
Lecture 6
Pavement Condition Survey & Evaluation
Text: Chap. 3-6: PM for Airport, Rds & Parking Lots (Shahin, M.Y., 2nd Edition)
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WHAT IS PAVEMENT PERFORMANCE?
Pavement’s efficacy to serve traffic over a
given period of time
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NEED FOR PAVEMENT CONDITION MONITORING
AND PERFORMANCE EVALUATION
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PAVEMENT CONDITION SURVEYS
Form a basis for evaluating pavement
performance
Evaluation of the condition is a
fundamental aspect of PMS
Assessing the pavement condition begins with collecting data.
Collection and analysis of pavement condition data forms the
foundation of an effective pavement management system 7
Typically, a system of objective measurements is used to
quantify a pavement's condition and performance.
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TYPES OF PAVEMENT CONDITION SURVEYS
Structural Capacity
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SURVEYS OF PAVEMENT
SURFACE DISTRESS
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DISTRESS SURVEYS
DISTRESS: Surface distress is damage
observed on the pavement surface.
Distress surveys are performed to determine
the type, severity, and quantity of surface
distress.
Common Distress Indicators:
Pavement condition index (PCI) – US Corps of
Engineers, Military airports
Pavement condition rating (PCR) – FHWA, DOTs
Present /Pavement Serviceability Rating/Index
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(PSR)/(PSI)
Manual vs. automated data collection
Manual: Visual, Windshield Survey
Automated: Image detection, Pattern recognition,
Signal processing, Artificial Intelligence
Pavement surface is viewed and evaluation
made to determine …
Type of distress (What?)
Severity of distress (How serious?)
Extent of distress (How much/many?)
Distress Type, Severity, and Extent help to …
get full picture of damage on pavement surface
determine appropriate category/type/timing of
remedial action for the pavement
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EXAMPLE DISTRESSES – FLEXIBLE PAVEMENT
EXAMPLE DISTRESSES – RIGID PAVEMENTS
HOW “BAD” IS AN EXISTING DISTRESS?
(ON BASIS OF EXTENT AND SEVERITY)
Rutting < 1/8 inch 1/8 - 1/4 inch 1/4 -1/2 inch >1/2 inch
FATIGUE CRACKING
Low Severity
High Severity
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FATIGUE CRACKING
Severity Levels
RUTTING
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MEASURING RUT DEPTHS
R0=D2 – (D +D )/2
1 3
R =D – (D +D )/2
i 4 3 5
where
R0 = rut depth outside wheel path estimate (mm);
Ri = rut depth inside wheel path estimate (mm);
R0 = is not less than 0;
Ri = is not less than 0; and 19
FAULTING OF TRANSVERSE JOINTS
AND CRACKS
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PAVEMENT CONDITION RATING (PCR)
Is a method that used by human inspectors to rate
pavement condition using visual examination
Provides a procedure for identifying and
describing, in terms of severity and extent,
pavement distress
Mathematical expression provides an index reflecting
the composite effects of varying distress types, severity,
and extent on overall pavement condition
n
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SURVEYS FOR PAVEMENT STRUCTURAL
CAPACITY
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FWD: OPERATION AND DATA ANALYSIS
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DESTRUCTIVE VS. NONDESTRUCTIVE EVALUATIONS OF
PAVEMENT STRENGTH
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PAVEMENT STRUCTURAL SURVEYS -
NON-DESTRUCTIVE TESTING
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PAVEMENT STRUCTURAL SURVEYS -
NON-DESTRUCTIVE TESTING
Performed using devices that measure strain
Broad categories:
Static devices – these measure the
pavement’s response to a static load or a
single application of a slow moving load.
Vibratory devices – these measure the
pavement’s response to a vibratory or
cyclical load
Impulse devices – these apply a load to the
pavement by dropping a known mass through a
known distance and measuring the pavement
response 30
PAVEMENT STRUCTURAL SURVEYS -
NON-DESTRUCTIVE TESTING
Static Devices
• Plate Bearing Tests
• Benkelman Beam
• Automated Deflection Beams
Vibratory Devices
• Dynaflect
• Road Rater
Impulse Devices
• Falling Weight Deflectometer (FWD)
• Rolling Wheel Deflectometer (RWD)
• Heavy Weight Deflectometer (HWD) 31
Plate Bearing Tests
Used to determine the bearing capacity and the load-deflection
relationship of the ground/or of materials used for roads, airport
runways, pavements
Relatively simple to operate and cost effective
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Direct measurement of
static, elastic k-value:
• new alignment:
on subgrade soil
• existing alignment:
remove surface and
base
• rarely used today
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PLATE LOAD TEST FOR K-VALUE
AASHTO T222
Three steel plates
k = p/
Where: p = applied pressure of 30” plate 34
• The tip of the beam is placed in front and between the tires
• 2000 lbs static and +/- 1000 lbs steady-state dynamic force
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Impulse Devices
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FALLING WEIGHT DEFLECTOMETER (FWD)
FWD measures surface deflections by an impact loading (7-150kN) to
simulate a vehicular moving load.
30 to 150m intervals
Both directions – staggered
Typically outer lane only
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HEAVY WEIGHT DEFLECTOMETER (HWD)
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Hot-mix asphalt
Base
Subbase
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Natural soil
Pavement Responses Under Load
Axle
Load
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ROUGHNESS (RIDE QUALITY)
Is a measure of pavement surface distortion along a linear plane
road users
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Why Roughness is an important
pavement characteristic?
It directly affects ride quality
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INTERNATIONAL ROUGHNESS INDEX (IRI)
Average rectified slope (ARS) = filtered ratio of a standard
vehicle's accumulated suspension motion (in mm, inches,
etc.) divided by the distance traveled by the vehicle (inches
per mile or meters per km)
C ) 80
g l e 80
(cents/veh-mile)
i
nm
i 60
t-
ah
r 40
ee
pv 60
/
20
Os
t
0
50
en
le 0 100 200 300 400 500 600 700 800 900
cc
i Roughness in IRI (in/mi)
h(
INTERNATIONAL ROUGHNESS INDEX (IRI)
Current practice is to measure roughness in terms of
the longitudinal profile of the road surface
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MANUAL PROFILOGRAPHS m
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Longitudinal Transverse
AUTOMATED PAVEMENT DATA
COLLECTION TECHNIQUES FOR SURFACE ROUGHNESS
Network-level roughness monitoring is conducted with instrumented
vehicles using accelerometers and at least one of three types of
sensors:
Lasers (e.g. laser receivers detect the absence and presence of single or
dual laser beams to determine the “vertical acceleration" of vehicles
Acoustic (audio sensors)
Infrared (electromagnetic radiation with a wavelength longer than that
of visible light)
Accelerometers provide a horizontal plane of reference; whereas the
sensors measure pavement deviations from a horizontal plane
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AUTOMATED PAVEMENT DATA
COLLECTION TECHNIQUES FOR SURFACE ROUGHNESS
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TYPICAL IRI RANGES BY PAVEMENT TYPE
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SKID RESISTANCE (SURFACE FRICTION)
Indicates ability of pavement surface to provide sufficient friction to
prevent vehicle skidding and concomitant safety problems
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MEASUREMENT OF SURFACE FRICTION
Portable Equipment
SN = 100 * f = 100 * F/ L
and µ = f = F/L
where
f = friction factor
F = frictional resistance force in plane of interface
L = vertical load.
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USES OF FRICTION DATA
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