Pavement Evaluation by Saadia

Pavement EvaluationPavement Evaluation 11


PPAVEMENT AVEMENT EEVALUATIONVALUATION

MSc. Transportation EngineeringMSc. Transportation EngineeringTeacher Incharge; Dr. Sajjad MaqboolTeacher Incharge; Dr. Sajjad Maqbool

Presented by; Saadia TabassumPresented by; Saadia Tabassum


““Pavement evaluation is a technique of assessing Pavement evaluation is a technique of assessing the condition of a pavement, both structurally the condition of a pavement, both structurally

and from the point of view of surface and from the point of view of surface characteristics”characteristics”

OObjectives;bjectives; To research on the performance of pavements of different To research on the performance of pavements of different

specifications over a period of timespecifications over a period of time To assess maintenance needs such as patch repairs, To assess maintenance needs such as patch repairs,

renewals and resealingrenewals and resealing To assess the need for structural overlay on distressed To assess the need for structural overlay on distressed

pavementspavements


Pavement Evaluation is a Measure of Pavement Pavement Evaluation is a Measure of Pavement PerformancePerformance

PPavement avement PPerformanceerformance is a function of its relative is a function of its relative ability to serve traffic over a period of time (Highway ability to serve traffic over a period of time (Highway Research Board, 1962). Research Board, 1962). Evaluation CategoriesEvaluation Categories

Roughness (often called “smoothness”)Roughness (often called “smoothness”)Surface DistressSurface DistressSkid ResistanceSkid ResistanceStructural EvaluationStructural Evaluation


Objective of various system of measurementObjective of various system of measurement (roughness meter, deflection, skid resistance (roughness meter, deflection, skid resistance

equipment, visual distress survey....etc.)equipment, visual distress survey....etc.)

Establish maintenance priorities Establish maintenance priorities Determine maintenance and rehabilitation Determine maintenance and rehabilitation

strategiesstrategies Predict pavement performancePredict pavement performance


Pavement RoughnessPavement Roughness “is an expression of irregularities in the “is an expression of irregularities in the

pavement surface that adversely affect the ride pavement surface that adversely affect the ride quality of vehicle (and thus the user).”quality of vehicle (and thus the user).”

Rough Pavements


Pavement RoughnessPavement Roughness Roughness MeasurementRoughness Measurement

Present Serviceability Rating (PSR)Present Serviceability Rating (PSR) International Roughness Index (IRI)International Roughness Index (IRI)

Measurement TechniquesMeasurement Techniques Rod & Level SurveyRod & Level Survey Dipstick ProfilerDipstick Profiler ProfilographsProfilographs Response Type Road Roughness Meter Response Type Road Roughness Meter (RTRRM)(RTRRM) Profiling DevicesProfiling Devices


Roughness MeasurementRoughness Measurement

Present Serviceability Rating (PSR)

"The judgment of an observer as to the current ability of a pavement to serve the traffic it is meant to serve" (Highway Research Board, 1962).

Individual Present Serviceability Rating Form


Roughness MeasurementRoughness Measurement

International Roughness Index (IRI)

"IRI is used to define a characteristic of the longitudinal profile of a traveled wheel track and constitutes a standardized roughness

measurement. The commonly recommended units are meters per kilometer (m/km) or millimeters per meter (mm/m).”

IRI Roughness Scale


Measurement TechniquesMeasurement Techniques

Categories of Equipments for roughness survey data collection

Roughness Measuring Equipment




Dipstick Profiler

Rod and Level survey

Dipstick Profiler (for small quantity of pavement profile measurement)




Profilograph

Profilographs

Profilograph Output

…..for rigid pavement construction inspection, quality control, and acceptance.…..not practical for network condition survey.




Response Type Road Roughness Meter (RTRRM)

….. RTRRM systems are adequate for routine monitoring of a pavement network and providing an overall picture of the condition of the network….. RTRRMs measure the vertical movements of the rear axle of an automobile or the axle of a trailer relative to the vehicle frame.




Profiling Devices

….. Profiling devices are used to provide accurate, scaled, and complete reproductions of the pavement profile within a certain range.

Van mounted road profiler Distress data collection van


Surface DistressSurface Distress “Any indication of poor or unfavorable “Any indication of poor or unfavorable

pavement performance or signs of impending pavement performance or signs of impending failure; any unsatisfactory performance of a failure; any unsatisfactory performance of a

pavement short of failure" pavement short of failure" (Highway Research Board, (Highway Research Board, 1970).1970).

Distress modesDistress modes Fracture (cracking or spalling)Fracture (cracking or spalling) Distortion (rutting, corrugation & shoving)Distortion (rutting, corrugation & shoving) Disintegration (striping, raveling or spalling)Disintegration (striping, raveling or spalling)


Surface DistressSurface Distress

Alligator Cracking Rutting

Corrugation & Shoving

Raveling Stripping

Joint reflection cracking

Water bleeding & Pumping Bleeding

Slippage Cracking

http://www.hawaiiasphalt.com/HAPI/modules/03_general_guidance/images/pavement_distress/fatigue_cracking1.jpg

http://www.hawaiiasphalt.com/HAPI/modules/03_general_guidance/images/pavement_distress/rutting1.jpg

http://www.hawaiiasphalt.com/HAPI/modules/03_general_guidance/images/pavement_distress/shoving1.jpg


Distress MeasurementDistress Measurement….either ….either SubjectiveSubjective or or ObjectiveObjective

Measurement TechniquesMeasurement Techniques Visual method – oldVisual method – old High speed imaging van –advance technologyHigh speed imaging van –advance technology

Equipped with high resolution camerasEquipped with high resolution cameras Specifically designed workstationsSpecifically designed workstations

AdvantagesAdvantages SafetySafety Accurate and complete distress dataAccurate and complete distress data Effective quality control systemEffective quality control system More efficient data collectionMore efficient data collection Video and digital images are available for other Video and digital images are available for other

usersusers



Visual Method



Pavement Condition Rating Van

Inside A Pavement Condition Rating Van

Screen Shot from a Computer-Based Automatic Crack Detection System


Skid ResistanceSkid Resistance “Skid resistance is the force developed when a “Skid resistance is the force developed when a tire that is prevented from rotating, slides along tire that is prevented from rotating, slides along

the pavement surface (Highway Research Board, the pavement surface (Highway Research Board,

1972).”1972).” Important Pavement Evaluation Parameter Important Pavement Evaluation Parameter

owing to;owing to; Inadequate skid resistance leads to higher accidentsInadequate skid resistance leads to higher accidents Obligation of agencies to provide user with reasonably Obligation of agencies to provide user with reasonably

safe roadwaysafe roadway Skid resistance measurements can be used to evaluate Skid resistance measurements can be used to evaluate

various type of material and construction particlesvarious type of material and construction particles


Skid Resistance MeasurementSkid Resistance Measurement

Quantified by;Quantified by; Friction Factor or Skid NumberFriction Factor or Skid Number

Friction factor (like a coefficient of friction): f = F/L

Skid number: SN = 100(f)

where: F = frictional resistance to motion in plane of interface

L = load perpendicular to interface


Skid Resistance MeasurementSkid Resistance Measurement

Typical Skid Number


Common MethodsCommon Methods The locked wheel testerThe locked wheel tester

…….this method uses a locked wheel .this method uses a locked wheel skidding along the tested surface to measure skidding along the tested surface to measure friction resistancefriction resistance. .


Lock Wheeled Skid Tester Lock Wheeled Skid Tester


The spin up testerThe spin up tester……. same basic setup as a locked . same basic setup as a locked

wheel tester but operates in an opposite wheel tester but operates in an opposite mannermanner

Surface texture measurementSurface texture measurement……. seeks to measure a . seeks to measure a

pavement's macro texture then correlate it pavement's macro texture then correlate it with skid resistance as measured by some with skid resistance as measured by some other, more traditional method other, more traditional method



Pavement Surface DeflectionPavement Surface Deflection “pavement deflection is a function of traffic “pavement deflection is a function of traffic

(type and volume), pavement structural section, (type and volume), pavement structural section, temperature affecting the pavement structure and temperature affecting the pavement structure and

moisture affecting the pavement structure.”moisture affecting the pavement structure.”


……measured as a pavement surface's vertical measured as a pavement surface's vertical deflected distance as a result of an applied deflected distance as a result of an applied (either static or dynamic) load. (either static or dynamic) load.

……advanced measurement devices record advanced measurement devices record this vertical deflection in multiple locations this vertical deflection in multiple locations

MMeasurementeasurement TTechniquesechniques Static deflections (static load)Static deflections (static load) Steady state deflections (oscillating load)Steady state deflections (oscillating load) Impact load deflections (impulse load)Impact load deflections (impulse load)

Pavement Deflection MeasurementPavement Deflection Measurement


Static Deflection EquipmentStatic Deflection Equipment Benkelman BeamBenkelman Beam

……operates on lever arm principleoperates on lever arm principle ……measurement is made by placing the tip of the beam measurement is made by placing the tip of the beam

between the dual tires and measuring the pavement between the dual tires and measuring the pavement surface rebound as the truck is moved awaysurface rebound as the truck is moved away


Benkelman Beam Schematic

Benkelman Beam in use


Steady State Deflection EquipmentSteady State Deflection Equipment DynaFlect & Road RaterDynaFlect & Road Rater

……consists of consists of a dynamic force generator (that produces the a dynamic force generator (that produces the

oscillating load), oscillating load), a motion measuring instrument (to measure the a motion measuring instrument (to measure the

oscillating load),oscillating load), a calibration unit and several deflection measuring a calibration unit and several deflection measuring

devices (transducers, accelerometers, seismometers, devices (transducers, accelerometers, seismometers, etc.).etc.).


Dynaflect

Road Rater


Impact (Impulse) Load ResponseImpact (Impulse) Load Response Falling Weight Deflectometer (FWD)Falling Weight Deflectometer (FWD)

……measures pavement response (deflection basin) by a measures pavement response (deflection basin) by a series of sensors series of sensors

... quicker and it more accurately simulates the transient ... quicker and it more accurately simulates the transient loading of traffic loading of traffic


FWD Impulse Loading Mechanism and Sensors

Sensors

Loading Plate (weight)


Pavement Condition Rating Systems Pavement Condition Rating Systems Based on measurements of roughness, surface Based on measurements of roughness, surface

distress, skid resistance and deflection, distress, skid resistance and deflection, pavements can be assigned a score that pavements can be assigned a score that evaluates it and thus reflects their overall evaluates it and thus reflects their overall condition.condition.

This score, sometimes called a pavement This score, sometimes called a pavement condition rating, quantifies a pavement's condition rating, quantifies a pavement's overall performance and can be used to help overall performance and can be used to help manage pavement networks. manage pavement networks.


pavement condition scores can be used to;pavement condition scores can be used to; Trigger treatmentTrigger treatment Determine the extent and cost of repairDetermine the extent and cost of repair. . Determine a network condition indexDetermine a network condition index. . Allow equal comparison of different pavementsAllow equal comparison of different pavements

Pavement Condition Rating Systems Pavement Condition Rating Systems


TThank hank yyouou

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Pavement Evaluation by Saadia

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