Framework for airfield pavements management—an approach based on cost-effectiveness analysis

14 Pages·2015·1.08 MB·English

by  Muhammad Irfan

Eur.Transp.Res.Rev.(2015)7:13
DOI10.1007/s12544-015-0165-5
ORIGINALPAPER
—
Framework for airfield pavements management an approach
based on cost-effectiveness analysis
MuhammadIrfan1&MuhammadBilalKhurshid2&ShahidIqbal1&AbidKhan2
Received:1June2014/Accepted:29March2015/Publishedonline:11April2015
#TheAuthor(s)2015.ThisarticleispublishedwithopenaccessatSpringerLink.com
Abstract andRe-constructionofcompleteairfield.Theanalysisresults
Purpose and research question The agencies responsible to revealedthatMilland2^thickACoverlayofmid-sectionwas
operateandmaintainairfieldsindevelopingcountriesmanage the most cost effective alternative entailing minimum cost
theairfieldpavementsonneedtodo/reactivebasisinsteadof whileyieldingmaximumbenefitpavementperformance.
resorting to performance based preventive maintenance and Conclusions The developed pavement management process
rehabilitation(M&R) activityprofiles. Extractingdue cogni- providessystematicandobjectiveproceduresformaintaining
zance from literature on internationally recognized airfield the inventory of pavement infrastructure, monitoring pave-
pavementsmanagementsystems,thisresearcharticlepresents ment performance,selecting optimal treatment and its appli-
aframeworkofthestep-wiseprocedureforairfieldpavement cationtime.Theproposedmanagementsystemfortheairfield
managementsystem. pavementswillnotonlyprioritizetheareasforrepair/main-
Methods M&R effectiveness is quantified based upon area tenance but also give a cost-effective solution for enhancing
boundedbythepavementperformancecurveandcostisthe theairfieldpavementservicelife..
presentworthoftotalcostincurredbytheagency.Theevalu-
ationandprioritizationofdifferentalternativesisbasedonlife Keywords Decisionsupportsystems .Lifecyclecosts .
cycle cost analysis and cost effectiveness index. The case Maintenance .Pavementmanagement .Rehabilitation .
study for an in-service airfield has also been presented to Statisticalmodels
demonstratetheapplicationofproposedmethodology.
Results TheevaluatedM&Ralternativesforagivenpreserva-
tionscenarioinclude:JointFilling,Patchingand2^thickover- 1Introduction
lay; Milling and 2^ thick AC overlay of mid-section (keel)
section; Replacement with complete 4^ thick AC Overlay; Airfieldspavements requirehuge investment ofpublic funds
forconstruction andsubsequentmaintenance purpose. These
pavementsarethebackboneoftheessentialeconomicactivi-
* MuhammadIrfan
tiesi.e.transportinggoodsandpersonsnotonlyinindustrial-
[email protected]
izedsocietiesbutalsoindevelopingcountries.Theincreasein
MuhammadBilalKhurshid
airtraffichassubjectedthesepavementstomoreloadsthanthe
[email protected]
pastandhaseffectedthesepavementstructureswhichareei-
ShahidIqbal
ther approaching or have exhausted their design life. Due to
[email protected]
thisdeterioration,theairfieldmanagementagencieshavegrad-
AbidKhan
ually shifted their emphasis from construction of new pave-
[email protected]
ments to maintenance and rehabilitation (M&R) of existing
1 MilitaryCollegeofEngineering(MCE),NationalUniversityof
ones. Managing an aging pavement network is difficult due
Sciences&Technology(NUST),Risalpur24080,Pakistan
tothecomplexbehaviorofpavement.Alsothegrowingbud-
2 NationalInstituteofTransportation(NIT),SchoolofCivil&
getaryconstraints,underwhichmostagenciesarenowforced
EnvironmentalEngineering(SCEE),NationalUniversityofSciences
andTechnology(NUST),Islamabad44000,Pakistan to fiscal parsimony, have caused reduction in maintenance
13 Page2of14 Eur.Transp.Res.Rev.(2015)7:13
activities.Inthelasttwodecades,researchproclivityhasbeen lifeanditalsocompareeffectivenessofdifferentpreservation
towards the development of airfield pavement management strategiesasshowninFig.1.
systems (APMS) bymany agencies.Themajorrole ofthese CurrentlyinPakistan,airfieldsmaintenanceandrehabilita-
systems is assisting decision-makers to find M&R strategies tiondecisionsarebasedonhistoricalpractices/experienceof
for maintainingairfieldpavements in a serviceable condition airfieldengineersanddiscretionofadministrativeauthorities
overaspecifiedtimeperiodinthemostcost-effectivemanner with no emphasis on life cycle cost analysis and other man-
[1].Dependingonthepreferencesoftheagency/organization agementpractices.Inthepresentenvironmentoffiscalparsi-
concerned, APMSs may take various forms, however all mony,thepavementinfrastructurerequiresamoresystematic
APMSs have some common elements/ functions, necessary and methodical approach for determining M&R needs and
foroperation.Theseimportantfunctionsarenetworkinvento- priorities. Mostly agencies in the country make decisions
ry,pavementconditionevaluation,pavementperformancepre- about pavement M&R based on instant needs or experience
dictionandplanningmethods.AnAPMSfacilitateslifecycle ratherthanlong-termplanningordocumenteddata.Thisap-
cost analysis (LCCA) for various alternatives and aids in proach did not allow the country’s management agencies to
decision-makingaboutthetimingofapplyingthebestalterna- evaluatethecosteffectivenessofalternativemaintenanceand
tive.Itprovidesasystematic,consistentmethodforselecting repairstrategies,whichresultedinaninefficientuseoffunds.
M&Rneedsanddeterminingprioritiesandtheoptimaltimeof Recent developmentsin airfield pavementmanagementpro-
repairbypredictingfuturepavementcondition[2].Itisavalu- videa wayforward inmanagingpavements timely and eco-
abletoolthatalertsthepavementmanageraboutacriticalpoint nomically. This research paper describes in detail an airfield
(oratrigger)fortheapplicationofappropriatetreatment(pre- pavementmanagementsystemforuseatairfieldsinPakistan
ventive maintenance (PM) or rehabilitation) in a pavement’s that will ensure examining the existing M&R practices and
life cycle as shown in Fig. 1, which indicates that the repair develop a framework for economical and effective expendi-
costsmaybereducedconsiderably,ifM&Risperformeddur- tureofmaintenancefundscommensuratewiththefunctional
ing the early stages of deterioration, before the pavement requirementsandtheplannedfutureuseofthefacilities.The
reachestheminimumlevelofserviceability(thresholdperfor- research study describes a stepwise procedure starting from
mance level) and needs complete reconstruction. Threshold pavementinventoryfollowedbyinspections/distresssurvey,
performancelevelortriggervalueistheminimumacceptable pavement performance evaluations and selection of M&R
performancelevelbelowwhichthepavementisconsideredto strategies.Thiswillenabletheairfieldmanagementagencies
be unacceptable for its designated function. These are often to prioritize the airfields pavements requiring M&R through
basedonagency’sperformancestandardsand/oruserperspec- judicious allocation of the available budget. In an effort to
tives.Often,agenciesseektoutilizethresholdvaluesthatare throwmorelightontheissue,thispaperuseshistoricalcon-
performance-basedratherthantime-based.Theshorttermef- ditiondataandactivityprofileofin-serviceairfieldpavements
fectivenessincludepavementperformancejump(Fig.1)andis and compare it with application of proposed APMS using
useful in simulations ofpavement performance andcompare varioussamplefeasibleM&Ralternatives.
effectiveness between alternative treatments, whereas long-
term effectiveness include service life extension, average
pavementperformanceandareaboundedbytheperformance 2Anappraisalofexistingairfieldpavement
curve and are appropriate for major preservation treatments, managementsystems
compared to minor treatments and useful for preservation
Bstrategies^ or Bschedules^ i.e., combinations of different Airfield pavement management system started in 1970s
treatmenttypesandtimingsoverassetlifecycleorremaining through a research conducted by Construction Engineering
Fig.1 Typicalpavementlife
cycleM&Rstrategiesand
performancecurve
Performance Jump
Airfield PM Treatment Rehab Treatment
Pavement
Condition
(PCI)
PM Treatment Trigger
Low Cost
Rehabilitation Treatment Trigger High Cost
Minimum Level of Serviceability (Threshold Performance Level) Very High Cost
Airfield Pavement Age, t
Eur.Transp.Res.Rev.(2015)7:13 Page3of14 13
ResearchLaboratory(CERL)forUSAirForce.Thisresearch assessingthedeformationresponsebyexaminingtheloading
managed to established PAVER and MicroPAVER manage- effects.Incaseofairfieldpavements,Non-destructivetesting
mentSystemstodeviseasystemthatprioritizesthebudgetfor (NDT) using heavy weight deflectometer (HWD) is useful
the Air Force bases as per their requirement (MicroPAVER because it generates much higher loadings than the actual
[3]).ThelatestversionofthesystemalsoincludestheForeign aircraft loadings. In addition, ground penetrating radar and
ObjectDamage(FOD) Index and structuralanalysisfor car- infraredthermalphotographyarespecificallyusefulinlocat-
rying out the residual life analysis. McNerney and Harrison ingvoidsunderthepavementsurface[16].TheNDTsenables
[4] conducted an analysis of various APMSs and concluded airfield managing agencies to conduct frequent surveys of
that the MicroPAVER was merely based on surface distress, their pavements’structural capacity and provides them with
andwastimeconsumingsystemthatdidnottakeintoaccount abasisfordecision-making.InAPMSs,variousperformance
theairlineandairfieldcostssuchascostsforuserdelaysasa predictionmodelsarecriticalelementsthatcontrolimportant
resultofclosedrunways,increasedroughnesscausingfatigue management decisions. Pavement performance serves as a
to aircraft. An Enhanced APMS (EAMPS), later developed, tool in the planning of future M&R actions and can be pre-
addressed the complete economic impact of pavement net- dicted through two types of models i.e., deterministic and
work that includes aircraft delay and operating costs (ARA probabilistic [17,18]. Functional performance models are
[5]).BrotenandWade[6]carriedoutasystematicassessment PCI prediction models that have mostly been developed for
and analysis of airport pavement management practices by PAVER system and are also used in other APMSs such as
conducting a survey of all states of US aviation agencies. Integrated APMS and AirPAVE (FAA [2,19]). The models
Severalstatetransportationagencies,notablyMichigan,Min- built for performance prediction relate the future PCI value
nesota, Ohio and California also developed comprehensive to a series of explanatory or predictive variables such as the
pavementmaintenanceguidelinesintheirrespectiveareasof age of pavement, time since last overlay, structural integrity
jurisdiction (MDOT [7]; MNDOT [8]; ODOT [9]; CalTrans (deflection measurement) and traffic, etc. Structural perfor-
[10]). U.S. Department of Defense issued Unified Facilities mancemodelsrelatethematerialscharacteristicsofthepave-
Criteria (UFC) publications, relevant reports and technical mentstructureandtheloadsappliedtoitfordeterminingthe
manualsonpavementmaintenancemanagement[11].Inad- numberofcyclesofloadapplicationsbeforetheoccurrenceof
ditiontoabovesystemswhichareapplicabletobothflexible failure. Such type of prediction models are widely used by
andrigidairfieldpavementsotherAPMSsthatarespecificto pavement managers and have been developed for pave-
pavementtypearealsoavailablee.g.,AirPACShasbeende- ments by various organizations i.e. Portland Cement As-
velopedtosolvedifferentproblemsrelatedtorehabilitationof sociation (PCA), Asphalt Institute, U.S Army Corps of
jointed plain concrete pavement (JPCP) airfield pavements Engineers and Shell International Petroleum Company
[12]. ([15]; Zaniewshi [20]).
ThemainelementsofalltheseAPMSsincludethenetwork Thedecision-makingandplanningincludedeterminingthe
inventory,differentmethodstoevaluateandratethecondition M&R actions that should be taken by the managing agency
of pavements, approaches used for predicting the evaluation keepinginviewthecurrentandpredictedpavementcondition
of pavement condition over time and lastly the planning withinitsjurisdictionandthebudgetaryresources/constraints.
methods.Theconditionsurveysareexpressedintheformof Lifecyclecostanalysisforagivensectionorprojectanalyzes
a quality index e.g. pavement condition index (PCI) corre- possible M&R alternatives that are expected to provide the
sponding to a single or combination of different pavement requiredperformanceinthepavementsectionandtoidentify
characteristics and represent the deterioration state of pave- themostcosteffectiveoneovertheanalysisperiod.Themost
mentatagiventime[13].ThePCIprocedureforcesthecol- advanced method for optimizing the allocation of available
lectionofalargedataregardingvariousdistressesforcomput- fundingusedbytransportationagenciesisthemulti-yearpri-
ingtheoverallindex.ThedrawbackinthePCImethodisthe oritizationusingincrementalcost-effectivenessanalysis,butis
dubious repeatability of visual surveys due to the subjective seldomimplementedforairportpavementnetworks.Therea-
nature and difference between the severities of distresses, sonsforslowerimplementationincludesmallerairportpave-
whichcanbecontrolledbyextensiveandmeticulousinspec- ment networks, greater importance of operational issues at
tion guidelines or by the use of automated data collection airports,andlimitationsofexistingairportpavementmanage-
devices [14]. In addition to the functional evaluations, the mentsoftware(ACRP[21]).
design and evaluation procedures of airfield pavements are TheappraisalofexistingstudiesonAPMSscontainsonlya
based on structural considerations such as limiting stresses, limitedselectionfromtheavailableinformation,withtheob-
strainsanddeflections[15].Thestructuralevaluationconsti- jective toprovide anoverviewofcommonairport pavement
tutesdeterminingthephysicalpropertiesofthepavementma- maintenance practices and their current application. Taking
terialse.g.,CaliforniaBearingRatio(CBR),modulusofelas- duecognizanceofavailableliterature,thisresearchstudycus-
ticity (E), sub-grade reaction modulus (K) etc. and then tomizes a framework for APMS that provides guidance for
13 Page4of14 Eur.Transp.Res.Rev.(2015)7:13
distresssurvey,monitoringpavementperformance,quantify- selection of the optimum M&R alternative is based on eco-
ing benefits and cost analyses, scheduling maintenance and nomicanalysis,pavementagency’smissionandmanagement
rehabilitation(M&R)basedoncost-effectivenessanalysisof policies. The ensuing sections explain the complete process
asphalt concrete (AC) and Portland cement concrete (PCC) foranairfieldpavementmanagementsystem.
airfields.
3.1Inventory/DataCollection
3Studymethodology For initiation of any management system the airfields pave-
mentsmustbedividedintovariouscomponentslikebranches,
The stepwise procedure of the developed framework is pre- sections and sample units. An airfield’s pavement network
sentedinFig.2.Theframeworkincludesanairfieldpavement branches consists of all surfaced areas that provide access to
management procedure based on the evaluation of distress groundorairtraffice.g.,runways,taxiways,aprons,roadsand
data,rateofdeterioration,andotherdirectmeasurementssuch storageareas.Asectionisadivisionofaparticularbranchwith
asskidpotentialandprofileroughness.Guidelinesforidenti- certainconsistentcharacteristics/attributesthroughoutitsarea/
fying different feasible M&R alternatives established on the lengthincluding:structuralcomposition(thicknessandmate-
results of the evaluation are also presented. Finally the rials);constructionhistory;traffic;andpavementcondition.
Fig.2 Developedframeworkof Collect Inventory Data
proposedairfieldpavement
(Network & Airfield)
managementsystem
Identify Network Collect Airfield Data
(Surface type, cross-sections,
(Branches, Sections & sample units)
history &previous M&R applied)
Establish Acceptable Levels of
Service (Target & Minimum)
Collect Condition Data,
Distress Survey (PCI)
No If, PCI< Acceptable Yes
Level of Service
Continue existing Pavement Evaluation/
maintenance policy Performance Modeling
(Routine Maintenance)
Is Pavement functionally/
structurally deficient?
No
Yes 1. Long or short-term rate of
pavement deterioration is high.
Identify feasible M&R
2. Deficient load carrying capacity.
alternatives
3. Dominant load-associated
distresses
4. Surface roughness rated as
Perform Life Cycle major.
Cost Analysis (LCCA)
5. Skid resistance / hydroplaning
potential is rated major.
6. High previous M&R applied.
Cost-effectiveness
7. A change in mission requires
Analysis greater load-carrying capacity.
Analyze results and select
optimal M&R strategy
Eur.Transp.Res.Rev.(2015)7:13 Page5of14 13
A sample unit is the smallest component of any airfield classification number (PCN) which shows the strength of
pavement network and is an area within a pavement section pavementandensurethatpavementisnotsubjectedtoexces-
obtainedbydividingsectionsintosampleunits.Inspectingan sive wear. The load-carrying capacity depends on the pave-
entire section requires considerable effort, especially if the ment structure and material properties including sub-grade
sectionisalargeone.Astatisticalsamplingplanistherefore soil properties. The load-carrying capacity of airfield pave-
developedtoobtainanadequatePCI.Theinspectioniscarried mentscanbedeterminedusingdifferentdestructivemethods
out on a portion of the sample units within that particular developed byFAAand U.S. ArmyCorps ofEngineers.The
section i.e., 20±8 slabs for rigid pavements, and 5,000±2, Non-destructive testing methods and criteria using falling
000squarefeetforflexible[22].Thestatisticalsamplingplan weight deflectometer (FWD) or heavy weight deflectometer
describedhereinwillconsiderablyreducethetimerequiredto (HWD)for evaluating the load-carrying capacity of airfield
inspectasectionwithoutsignificantlossofaccuracy.Assum- pavementsareusedtoassessthestructuralcapacityofpave-
inganormaldistributionofdata,thenumberofsampleunits mentwithoutanycoresordestructioninaquicktime[22].
to be surveyed having 95 % confidence level can be deter-
minedusingEq.(1): 3.2Pavementperformanceprediction
(cid:1) (cid:3)
n¼Nσ2= e2=4ðN−1Þþσ2 ð1Þ
Pavement deterioration over the years is estimated through
pavement performance models [21, 23]. Knowledge of the
Where
performance trend subsequent to each treatment application
n numberofsampleunitstobeinspected is helpful in M&R strategy optimization because it enables
N totalnumberofsampleunitsinfeature anestimationofthetimewhenthenextmaintenance,rehabil-
σ standarddeviationinPCIbetweensampleunitswithin itationorreconstructiontreatmentwouldbeneeded.Deterio-
thefeature(10and15forflexibleandrigidpavements, rationofapavementsectiondependsuponlocalfactorssuch
respectively) as the type and number of traffic loadings, environmental
e allowableerrorindeterminingthetruePCI conditions,andsubgradestrengthincludingdrainageandma-
terialcharacteristics.Theselectionofpavementperformance
modelsdependsondataavailabilityandotheragencyrequire-
Airfielddata Theextentandtypesofmaintenanceprevious- mentstoestimatefuturepavementpreservationneeds.Under-
ly applied to a pavement section must be determined before standingthetreatment-specificperformancemodelishelpful
selectinganewstrategy.Followingdataiscompiledforsub- inM&Rstrategyoptimizationinestimatingthetimewhenthe
sequentuseduringtheconditionsurvey:design/construction/ next maintenance, rehabilitation, or reconstruction would be
maintenancehistory;airtraffichistory(includingaircrafttype, needed,andthereforecanfacilitatethedevelopmentofrealis-
typical gross loads, frequency of operation, runway usage, tic schedules and budgets for long-term pavement preserva-
taxiway and apron usage); climatic/meteorological data (in- tion. The general functional form of post-treatment perfor-
cludingfrostaction,etc.),airfieldlayoutplansincludingpho- mancetrendforairfieldpavementsconsideredinthisresearch
tographs,pavementconditionsurveyreports. studyisgiveninEq.(2)[23]:
Pavementfunctionalandstructuralevaluation Examining PI¼ fðtÞ ð2Þ
thedistressespresentinapavementsectionhelpinidentifying
thecauseofpavementdeterioration,itsextentandeventually Where:PI=Performanceindicator(PCI)inagivenyear,t;
itsM&Rneeds.Inaddition,theeffectofdrainageondistress (PCIiscalculatedbysubtractingtotaldeductvaluewhichisin
occurrenceisalsoinvestigatedbecause moisturehas consid- turn a function of accumulated effect of distress levels and
erableeffectontherateofdistressoccurrence.Also,thedrive extents expressed as a numerical index between 0 and 100
throughinspectionchecksisconductedforanyFOD,whereas whichisusedtoindicatethegeneralconditionofapavement.
thequarterlyinspectionreportrecordsthecompletepavement Thestepsinvolvedinpavementconditionevaluationsareil-
inventory and any other abnormality on the airfield. Minor, lustrated in Fig. 3); f(t)=Function of pavement intervention
moderate,ormajorsurfaceroughnessisdeterminedbyriding age, t (or a surrogate of age, such as accumulated aircraft
profilersoverthepavementsectionatitsspeedlimitandob- trafficloadsand/orclimaticeffects,etc.)
serving its relative riding quality. Distresses that can cause Airfieldpavementperformancetrendonapplicationofdif-
skid resistance / hydroplaning potential for runways include ferent treatments generally, is a function of load characteris-
bleeding,polishedaggregates,rutting,anddepression(foras- tics,typeofintervention(appliedtreatment),climaticeffects,
phaltpavements)and polishedaggregate (forconcretepave- moistureand other variablefactors.As anexample the need
ments)alsoneedtobesurveyed.Theloadcarryingcapacityof for performance prediction and the rate of deterioration for
an airfield pavement is defined in terms of pavement different treatments is illustrated in Fig. 4, which shows
13 Page6of14 Eur.Transp.Res.Rev.(2015)7:13
Fig.3 Stepsinvolvedin
pavementconditionevaluations
pavementperformancetrendcurvesfortwopavements.Both ofservicetheneedforpavementpreservationarises.Khurshid
pavementshavesameinitialPCIbutpavementBdeteriorates et al.[25]) developed a framework for establishing optimal
atafasterratethanpavementA,thuspavementBwillrequire performance thresholds for highway asset interventions.
anearlierpavementpreservationtreatmentthanpavementA. Treatmentspecifictriggerlevelsrelatetoapplicationofpres-
Aspavementconditionreachesaminimumacceptableservice ervationtreatmentsattherighttimewithinaspecifiedrangeto
level the pavement requires maintenance or rehabilitation. be effective, before the PCI falls below the level where the
Feedbackonthealternativesappliedcanbejudgedbymoni- pavement condition require different and more expensive
toringtheperformanceovertheyears.Figure1illustratesthe treatmente.g.,crackssealinginACpavementsismosteffec-
concept of sudden elevation of pavement performance upon tive when the pavement is still in a good condition. For the
treatment (short-term effectiveness) and deterioration trend purposeofthisresearch,theexistingestablishedperformance
subsequentto the treatment application (long-term effective- standardsdevelopedbyairportcooperativeresearchprogram
ness).Performancemodelsenabletrackingofpavementper- sponsored by Federal Aviation Administration (FAA) were
formanceoverthelife-cycleandarethereforeavitalinputof adopted(Table1)forselectingtheapplicationthresholdsfor
thetreatmenteffectivenessperspective.Theremainingservice variousM&Rtreatments(ACRP[21]).
lifeisusedtocalculate the salvage value ofpavementwhile
carryingouttheeconomicanalysisandalso,isanindicatorof
3.4Quantifyingthebenefitsofpreservationtreatments
theoverallconditionofthenetwork[24].Theremainingser-
vicelifeforpavementBis‘2’yearsandthatforpavementAis
Theconceptofareaboundedbypost-treatmentperformance
‘5’yearsasillustratedinFig.4.
curveintegratesthemeasuresofeffectiveness(MOEs)ofser-
vice life and increase in average asset performance and is
3.3Identificationofpreservationneeds consistent with the rationale that superior average perfor-
manceoveralongerperiodprovidesmorebenefitscompared
The establishment of the minimum acceptable levels of ser- toinferiorperformanceoverashorterperiod(Lamptey[26]).
vicealsoprovidesrationaljustificationforpavementmainte- For the non-increasing performance indicators, such as PCI
nanceandrehabilitationneeds.Wheneverthepredictedpave- thiseffectivenessistheareaunderthecurve(AUC)(Fig.5).
mentconditionfallslowerthantherecommended/targetlevel The benefits of a well-maintained airfield pavement are
Fig.4 Pavementperformance
curvefordifferenttreatments B Predicted Performance
(AdaptedfromACRP[21]) 100
Remaining Service Life
Airfield
Pavement A
Condition
(PCI) Past Performance
Minimum Level of Serviceability
(Threshold Performance Level)
0
Now Now +2 Now +5
Airfield Pavement Age, years
Eur.Transp.Res.Rev.(2015)7:13 Page7of14 13
Table1 PavementPerformanceStandardsforAirportPavements(ACRP[21])
PavementCondition Performancedescription Applicablepavementpreservationtreatments
Index(PCI)
86–100 Good—onlyminordistresses Routinemaintenanceonly
71–85 Satisfactory—lowandmediumdistresses Preventivemaintenance
56–70 Fair—somedistressesaresevere Preventivemaintenanceandrehabilitation
41–55 Poor—severityofsomeofthedistressescancauseoperationalproblems Rehabilitationorreconstruction
26–40 Verypoor—severedistressescauseoperationalproblems Rehabilitationandreconstruction
11–25 Serious—manyseveredistressescauseoperationalrestrictions Immediaterepairsandreconstruction
0–10 Failed—pavementdeteriorationpreventssafeaircraftoperations Reconstruction
numerousandmaybedifficulttoquantifyinmonetaryterms. PI Post-treatmentperformancemodelforithstage
s,i
Inpavementmanagementresearch,thisnon-monetizedbene- treatmentatanyyear,t
fit or effectiveness is often expressed in at least one of the t =t(i) Actualservicelifeofthe(i–1)thtreatment
s(trig)
threeforms:servicelifeextension,averagepavementperfor- (thetimebetweenthetriggeringofithtreatment
manceandareaboundedbytheperformancecurve.Thecon- andthetimewhentheprevious[(i—1)th]
ceptofareaboundedbytheperformancecurveisconsidered treatmentwasimplemented)
superior to the others as it embodies the concepts of service t Timeorage,tatminimumacceptable
ps(max)
life and increased condition. This is consistent with the rea- performance(serviceability)ofpre-treatment
soningthatsuperioraverageconditionforlongerperiodspro- (ps)
videsmorebenefitthaninferiorconditionforshorterperiods t Timeorage,tatminimumacceptable
s(max)
[23]. The mathematical form of the post treatment-specific performance(serviceability)of
area bounded by the performance curve is given in Eq. (3) triggered-treatment(s)
forthedecreasingperformanceindicator:
2Z (Z )3
AUCs;i¼64 t0sðmaxÞPIs;idt– ttpsðstðrmigaÞxÞP(cid:1)Is;0dt−PImax(cid:3):(cid:1)tpsðmaxÞ−tsðtrigÞ(cid:3) 75 M&ARsismtrpatleegcyalccoumlaptiroisninogf mthueltoipvleeratlrleaetfmfeecntitvsefnoelsloswoifnga
−PImax: tsðmaxÞ−tsðtrigÞ the initial construction is illustrated in Fig. 4 and is
ð3Þ given in Eq. (4) for the decreasing performance indica-
tor (PCI):
Where
AUCs Additionalareaundertheperformancecurve Effectivenessof M&RStrategy
yieldedbytreatment,s. Z
PI Performancemodelfornewconstructionin X X tðiÞ
s,0 termsofperformanceindicator(PI) ¼ ks¼1 ni¼0 PIs;tdt−PImax:tðiÞ ð4Þ
0
Fig.5 Illustrationofquantifying Area under the Performance Curve
thepavementtreatment
Post-treatment
effectiveness Airfield Pre-treatment, PI(s,0) Performance Post-treatment
Pavement PI(s,1) Performance,
Condition, PCI PI(s,2)
PIs(trig)
PImax
Minimum Level of Serviceability (Threshold Performance Level)
0 t(0) t(1) t(2)
Airfield Pavement Age, t
13 Page8of14 Eur.Transp.Res.Rev.(2015)7:13
Where recycling of existing pavements and total reconstruction
fall under the category of overall M&R.
s thenumberofalternativeM&Rtreatmentsinthegiven
strategy(s=1,2,…,k)
3.6EconomicanalysisofM&Ralternatives
i thenumberofpossibletriggeringstagesoftreatments
(includingnewconstruction)intheanalysisperiod(i=0,
Selectingthebestalternativerequiresperforminganeconomic
1,2,…,n)
analysistocomparethecost-effectivenessofallfeasiblealter-
All other notations have their usual meaning previously natives[27].Aneconomicanalysisprocedure,alsocalledlife
explained. cyclecostanalysis,comparesM&Ralternativesusingpresent
worth (for equal analysis periods of alternatives: Eq. (5)) or
equivalentuniformcost(forvaryinganalysisperiodsofalter-
3.5PreservationscenariosandfeasibleM&Ralternatives
natives).ThepresentworthofanyM&Ralternativeisthesum
ofalldiscountedM&Rcostsduringtheanalysisperiodminus
Literaturesearchrevealedalargeamountofinformationavail-
thesalvagevaluediscountedtothepresent.Thepresentworth
able apropos the technology of pavement preservation treat-
ofallM&Ralternativesiscomparedwithrespecttoavailable
ments (ACRP [21]). As such, different agencies could have
budget in order to guide the pavement manager in selecting
different customized set of feasible treatments for different
themostsuitablealternative.
preservationscenarios:
X
MinorLocalized(Routine)M&R MinorlocalizedM&Rin- PWC¼ICþ k M&R (cid:2)½1=ð1þirÞ(cid:3)nj−SV½1=ð1þirÞ(cid:3)N
j¼1 j
cludesmethodsthatpreservetheconditionofthepavementand ð5Þ
retard its deterioration. These methods may include crack
sealing,jointsealingandapplicationoffogsealsandrejuvena-
Where:
tors.MinorlocalizedM&Rmethodsalsorestorepavementcon-
ditione.g.,skinpatching,applyingheatandrollingsand,plac- PWC Presentworthofcostofastrategyapplication
ingsmallpatchesandpatchingjointandcornerspall. IC Presentcostofinitialconstructionorrehabilitation
activity
Major Localized (Preventive) M&R Major localized M&R k NumberoffutureM&Ractivities
includespartialdepthorfull-depthpatching,slabreplacement, M&R CostofjthfutureM&Ractivityintermsofpresent
j
slabundersealingandslabgrindingappliedtoalargerareaor costs
portion of the pavement section. Other major localized M&R ir Discountrate
may include application of an aggregate seal over the entire n NumberofyearsfrompresenttothejthfutureM&R
j
section(micro-surfacing,thinoverlays,etc.)inACpavements activity
andreconstructionofjointsinaconcretepavement. SV Salvagevalue;and
N Analysisperiodlength,years
Overall M&R Overall M&R includes all methods that
cover the entire pavement section and improves its Knowing the benefitsand costs of a M&R strategy, asset
structural capacity. Overlays of asphalt (including mill- managers can compare the overall desirability of alternative
ing of AC pavements) or PCC overlays, hot & cold treatments or strategies and select the best alternative on the
Fig.6 Comparisonofvarious
activityprofileseffectiveness
Eur.Transp.Res.Rev.(2015)7:13 Page9of14 13
Table2 NetPresentworthofsamplefeasibleM&Ralternatives(a)Patchingandapplycomplete2^thickoverlay
Year Workdescription Quantity Unitcost Totalcost PWF Presentworth
(0)2011 CrackFilling 1274m 198 2,52,252 1.000 2,52,252
(0)2011 Patching 570.3Ton 5938.3 33,86,613 1.000 33,86,613
(0)2011 TackCoat 125,464m2 41.14 51,61,618 1.000 51,61,618
(0)2011 2^ACOverlay 15,010Ton 5938.3 8,91,33,883 1.000 8,91,33,883
(5)2016 Fogseal 125,464m2 95.14 1,19,36,645 0.822 98,11,922
(8)2019 SealCracks 1274m 198 2,52,252 0.730 1,84,144
(10)2021 Removalof2^AC 6373.7cum 855.38 54,51,936 0.676 36,85,508
(10)2021 Overlay2^AC 15,010Ton 5938.3 8,91,33,883 0.676 6,02,54,505
(15)2026 FogSeal 125,464m2 95.14 1,19,36,645 0.555 66,24,838
(18)2029 SealCracks 1274m 198 2,52,252 0.494 1,24,612
SubTotal 17,86,19,895
LessSalvageValue 0
NetPresentWorth 178.62MillionPKR
basisofcost-effectiveness[28].Inanefforttoavoidtheissues 4Applicabilityofproposedframework–acasestudy
associated with monetization of benefits, a number of past ofin-serviceairfield
studies resorted to using non-monetized benefits such as the
areaboundedbythecurve,theservicelife,thedecreaseinthe Acasestudyofanin-serviceairfieldisundertakentoperceive
structuralindexetc.[28–30].Thecost-effectiveness(CE)In- theefficacyoftheproposedAPMSframework.Thesampling
dexofeachM&RstrategyiscalculatedusingEq.(6): anddatacollectionplanincludedtheextractionofpavement
EffectivenessðBenefitÞ condition data from annual serviceability reports of selected
CostEffectivenessðCEÞIndex¼ ð6Þ in-service airfields. The data in the serviceability report pro-
PWC
videaninformationofdistresstype,itsextentandM&Rac-
The evaluation and decision-making of optimal M&R tiontaken(ifany).However,itdoesn’tprovideotherpertinent
scheduleforagivenairfieldpavementnetworkismadeusing informationneededforAPMSregardingdistresscause,eval-
brute-forceenumeration(alsoreferredtogenerate-and-test)of uation procedure, feasible M&R alternatives and cost effec-
all feasiblealternativeswhich isproceeded bygeneratingall tivenessanalysis.Theairfieldhistoricaldataindicatesthatthe
possible candidate feasible strategies (ARA [5]) randomly runway(RW16/34)wasrehabilitatedwith2^thickOverlayin
followedbydeterminingwhetheritisa validsolutiontothe 1997. The same year is considered as the start point for the
budgetaryortheperformanceconstraint. activity profile as shown in Fig. 6. The actual activity
Table3 NetpresentworthofsamplefeasibleM&Ralternatives(b)Replacementof2^thickACOverlayofKeelSection
Year Workdescription Quantity Unitcost Totalcost PWfactor Presentworth
Rs Rs Rs
(0)2011 Removalof2^ACsurface 2124.6m3 855.38 18,17,340 1.000 18,17,340
(0)2011 TackCoat 41,822m2 41.14 17,20,557 1.000 17,20,557
(0)2011 2^ACOverlay 5004Ton 5938.3 2,97,15,253 1.000 2,97,15,253
(5)2016 Fogseal 125,464m2 95.14 1,19,36,645 0.822 98,11,922
(8)2019 SealCracks 1274m 198 2,52,252 0.730 1,84,144
(10)2021 TackCoat 125,464m2 41.14 51,61,618 0.676 34,89,254
(10)2021 Overlay2^AC 15,010Ton 5938.3 8,91,33,883 0.676 6,02,54,505
(15)2026 FogSeal 125,464m2 95.14 1,19,36,645 0.555 66,24,838
(18)2029 SealCracks 1274m 198 2,52,252 0.494 1,24,612
SubTotal 11,37,42,425
LessSalvageValue 0
NetPresentWorth 113.74MillionPKR
SalvageValueofzeroindicatesthat2^ACoverlayhavecompleteditsusefullife
13 Page10of14 Eur.Transp.Res.Rev.(2015)7:13
Table4 NetpresentworthofsamplefeasibleM&Ralternatives(c)ReplacementofComplete4^thickACOverlay
Year Workdescription Quantity Unitcost Totalcost PWFactor Presentworth
Rs Rs Rs
(0)2011 Removalof4^ACsurface 12,620m3 855.38 1,07,94,896 1.000 1,07,94,896
(0)2011 TackCoat 125,464m2 41.14 51,61,618 1.000 51,61,618
(0)2011 2^ACAggregate 14,405T 5617.3 8,09,17,207 1.000 8,09,17,207
(0)2011 Tackcoat 125,464m2 41.14 51,61,618 1.000 51,61,618
(0)2011 2^ACwearing 15,010T 5938.3 8,91,33,883 1.000 8,91,33,883
(08)2019 Fogseal 125,464m2 95.14 1,19,36,645 0.730 87,13,751
(11)2022 Crackseal 1274m 198 2,52,252 0.650 1,63,964
(14)2025 TackCoat 125,464m2 41.14 51,61,618 0.577 29,78,254
(14)2025 2^ACoverlay 15,010Ton 5938.3 8,91,33,883 0.577 5,14,30,250
(19)2030 FogSeal 125,464m2 95.14 1,19,36,645 0.475 56,69,906
SubTotal 3,56,53,553 0.456 26,01,25,347
LessSalvageValue 1,62,58,021
NetPresentWorth 243.87MillionPKR
SalvageValue=(Remainingservicelifeoflastrehabilitationtreatment/ExpectedLifeofRehabilitationTreatment)×cost;ExpectedLifeof2^AC
Overlayinallalternatives=10years.RemainingserviceLifeafter20thyear=4years
performedduringthesubsequentyearsisshownwhichindi- treatmentbeenappliedbeforethecrackappearedi.e.in2002,
catesthatfromyear1997toyear2007nopreventivemainte- itwouldhavemaintainedtheconditionlevelatanacceptable
nance was carried out, despite the appearance of cracks in servicelevelforconsiderableperiodandenhancedthepave-
2004.Thisledtothecontinuousdropinthe conditionlevel, mentlife(Tables2,3,4and5).
whichultimatelyfellbelowtheminimumacceptablelevelin AssumingtheproposedAPMSwasadoptedandtheover-
year 2007. Instead of rehabilitation with 4^ thick overlay, allM&Rstrategyscenarioisconsideredforthecasestudyof
routine maintenance (seal coat) was conducted. Then after a runway (Fig. 6). The sample feasible alternatives
lapseofjustoneyear(i.e.in2008)againroutinemaintenance (rehabilitation) in year 2011 in addition to routine mainte-
(crackseal)wascarriedout.Theconditionlevelcontinuedto nancecouldinclude:
deteriorateandfinallyin2011,agencyresortedtoreconstruc-
tion.InordertodeterminetheoptimalM&Ractivityprofiles, & Performpatchingandapplycomplete2^thickoverlay.
agencies mustbe ableto predict the performance trendsand & Performmillingandreplacethekeel(central)portionwith
futureconsequencesofthevariouspreservationscenarios.In 2^thickoverlay.
the above presented casestudy, had the routine maintenance & Replacementof4^thickACintwolifts.
Table5 NetPresentWorthofSampleFeasibleM&RAlternatives(d)Re-constructionofCompleteRunway
Year Workdescription Quantity Unitcost Totalcost PWfactor Presentworth
Rs Rs Rs
(0)2011 Removal12^AC 38,242m3 855.38 3,27,11,442 1.000 3,27,11,442
(0)2011 Removal11^sub-base&base 35,055m3 180.48 63,26,726 1.000 63,26,726
(0)2011 Laying9^sub-base 28,681m3 1031.30 2,95,78,715 1.000 2,95,78,715
(0)2011 Laying7^base 22,308m3 1459.30 3,25,54,064 1.000 3,25,54,064
(0)2011 Primecoat 125,464m2 78.44 2,52,252 1.000 2,52,252
(0)2011 2^ACAggregate 14,405T 5617.3 8,09,17,207 1.000 8,09,17,207
(0)2011 Tackcoat 125,464m2 41.14 51,61,618 1.000 51,61,618
(0)2011 2^ACwearing 15,010T 5938.3 8,91,33,883 1.000 8,91,33,883
(14)2025 Fogseal 125,464m2 95.14 1,19,36,645 0.577 68,87,444
(19)2030 Crackseal 1274m 198 2,52,252 0.513 1,19,820
SubTotal 28,36,43,171
LessSalvageValue 5,53,27,181
NetPresentWorth 22,83,15,990or
228.32MillionPKR