Advisory Circular page...Evaluating pavement condition 3 Surface defects 4 Surface deformation 5...

U.S. Department of Transportation Federal Aviation Administration

Advisory Circular

Subject: AIRFIELD PAVEMENT SURFACE EVALUATION AND RATING MANUALS

Date: 7/12/04 Initiated by: AAS-100

AC No: 150/5320-17 Change:

1. PURPOSE. This Advisory Circular (AC) provides guidance on understanding and rating the surface condition of flexible and rigid airfield pavements. It describes types and causes of distress and provides a simple system to visually rate pavement condition on a scale ranging from excellent to failed. 2. BACKGROUND. The Federal Aviation Administration (FAA) evaluated options for improving the quality of information available to the Agency on airfield pavement conditions in response to Section 160 of the Wendall H. Ford Aviation Investment and Reform Act for the 21st Century (P.L. 106–181). The evaluation resulted in selecting an existing inexpensive pavement condition rating system to adapt for use on airfield pavements. The rating system is modeled after the University of Wisconsin's Pavement Surface Evaluation and Rating System (PASER). The rating system is meant as a source of information for rating pavements under the airport safety data program. The manuals will also assist airport managers in understanding the surface condition of airfield pavements. These manuals were produced for the FAA by Engineering Professional Development, College of Engineering, University of Wisconsin–Madison. 3. APPLICATION. The FAA recommends the information and procedures contained in the manuals for use by airport staff and consultants directly or in combination with additional testing and data collection in a more comprehensive pavement maintenance management system. DAVID L. BENNETT Director, Office of Airport Safety and Standards

The information in this AC is not intended to decide the need or timeliness for pavement rehabilitation projects. These decisions should be determined as a result of more technical investigations that may include a detailed pavement condition index (PCI) study. The manuals will help provide a degree of uniformity to field observations made by individuals collecting data for the Airport Master Record (FAA Form 5010). The data element description for Surface Type/Condition (Data Element 33 of the National Airspace System Resources database) has been revised to incorporate information from this AC. The manual for asphalt airfield pavements is included in this AC as Appendix 1. The manual for concrete airfield pavements is included as Appendix 2. 4. RELATED READING MATERIAL. AC 150/5380-6, Guidelines and Procedures for Maintenance of Airport Pavements, and AC 150/5380-8, Handbook for Identification of Alkali-Silica Reactivity in Airfield Pavements provide additional guidance and technical information for identifying distresses in airfield pavements. 5. ONLINE AVAILABILITY. To view and download this AC, visit the FAA Web site at http://www.faa.gov/arp/150acs.cfm.

http://www.faa.gov/arp/150acs.cfm

AC 150/5320-17 Appendix 1 7/12/2004

APPENDIX 1--ASPHALT AIRFIELD PAVEMENT SURFACE EVALUATION AND RATING MANUAL

Pavement Surface Evaluation and Rating

PASERManualAsphalt Airfield Pavements

RATING5

RATING3

RATING1

This manual is intended to assist airfield managers inunderstanding and rating the surface condition of asphaltpavement. It describes types and causes of defects and provides a simple system to visually rate pavement condition.

Produced for the Federal Aviation Administration by Engineering Professional Development, College of Engineering,University of Wisconsin-Madison.

Contents

Introduction 2

Evaluating pavement condition 3

Surface defects 4

Surface deformation 5

Cracks 7

Patches and potholes 12

Rating pavement surface condition 14

Rating system 14

Rating 5 — Excellent 15

Rating 4 — Good 16

Rating 3 — Fair 18

Rating 2 — Poor 20

Rating 1 — Failed 22

Practical advice on rating airfield pavements 23

Airfield Pavement Inventory inside back cover

AC 150/5320-17 Appendix 1 7/12/04

Donald Walker, P.E., University of Wisconsin–Madison, author

Lynn Entine, Entine & Associates, editor

Susan Kummer, Artifax, designer

PASERManual


Asphalt Airfield Pavements

AC 150/5320-17 Appendix 1 7/12/04

An airport manager’s goal is to use available funds to provide a safeand economical pavement surface—no simple task. It requiresbalancing priorities and making difficult decisions in order tomanage pavements. General aviation airfield pavements are oftenmanaged informally, based on the staff’s judgment and experience.While this process is both important and functional, using a slightlymore formalized technique can make it easier to managepavements effectively.

Experience has shown that there are three especially useful stepsin managing pavements:

1) Inventory all pavements.

2) Periodically evaluate the condition of all pavements.

3) Use the condition evaluations to set priorities for projects and evaluate alternative treatments.

A comprehensive pavement management system involvescollecting data and assessing several pavement characteristics:roughness, surface distress (condition), surface skid characteristics,drainage, and structure (pavement strength and deflection).Planners can combine this condition data with economic analysis,to develop short-range and long-range plans for a variety of budgetlevels. However, general aviation agencies may lack the resourcesfor such a full-scale system.

Since surface condition is the most vital element in any pavementmanagement system, managers may use the simplified ratingsystem presented in this manual on asphalt airfield pavements toevaluate their asphalt pavements. A PASER manual for concreteairfield pavements is also available (see references, page 24).

PASER — Pavement Surface Evaluation and Rating

Asphalt Airfield Pavements

3

AC 150/5320-17 Appendix 1 7/12/04

PASER uses visual inspection to evaluatepavement surface conditions. The key to auseful evaluation is identifying differenttypes of pavement distress and linkingthem to a cause. Understanding the causefor current conditions is important inselecting an appropriate maintenance orrehabilitation technique.

There are four major categories ofcommon asphalt pavement surfacedistress:

Surface defectsRaveling, flushing, polishing.

Surface deformationRutting, distortion — rippling andshoving, settling, frost heave.

CracksThermal, reflection, slippage, joint/edge, block, and alligator cracks.

Patches and potholes

Deterioration has two general causes:environmental due to weathering andaging, and structural caused by repeatedtraffic loadings.

Obviously, most pavement deteriorationresults from both environmental andstructural causes. However, it is importantto try to distinguish between the two inorder to select the most effectiverehabilitation techniques.

Evaluating pavement condition

The rate at which pavement deterio-rates depends on its environment, trafficloading conditions, original constructionquality, and interim maintenanceprocedures. Poor quality materials or poorconstruction procedures can significantlyreduce the life of a pavement. As a result,two pavements constructed at the sametime may have significantly different lives,or certain portions of a pavement maydeteriorate more rapidly than others. On the other hand, timely and effectivemaintenance can extend a pavement’s life.Crack sealing and surface treatments(such as slurry seal) can reduce the effectof moisture in aging of asphalt pavement.

With all of these variables, it is easy tosee why pavements deteriorate at variousrates and why we find them in variousstages of disrepair. Recognizing defectsand understanding their causes helps usrate pavement condition and select cost-effective repairs. The pavement defectsshown on the following pages provide abackground for this process.

Periodic inspection is necessary toprovide current and useful evaluationdata. It is recommended that PASERratings be updated every year.

EVALUATION — Surface Defects4

AC 150/5320-17 Appendix 1 7/12/04

SURFACE DEFECTS

RavelingRaveling is progressive loss of pavementmaterial from the surface downward,caused by: stripping of the bituminousfilm from the aggregate, asphalthardening due to aging, poor compaction especially in cold weatherconstruction, or insufficient asphaltcontent. Slight to moderate ravelinghas loss of fines. Severe raveling has loss of coarse aggregate. Debrisfrom raveling may damage aircraft.Protect pavement surfaces from theenvironment with a surface treatmentor an overlay if additional strength isrequired.

PolishingPolishing is a smooth slippery surfacecaused by traffic wearing off sharpedges of aggregates. Pavement groovesmay also be worn away. Repair withsurface treatment or thin bituminousoverlay using skid-resistant aggregate.

FlushingFlushing is excess asphalt on thesurface caused by a poor initial asphaltmix design or by paving or sealcoatingover a flushed surface. Repair byoverlaying with properly designedasphalt mix or sealcoat.

Slight raveling. Smallaggregate particles haveworn away exposing topsof large aggregate.

Moderate to severeraveling. Erosion furtherexposes large aggregate.

Severe raveling and lossof surface material.

Polished, worn aggregateneeds repair.

Flushing.Dark patchesshow whereasphalt hasworked tosurface.

▼

▼

▼

▼

▼

EVALUATION — Surface Deformation 5

SURFACE DEFORMATION

RuttingRutting is displacement of material,creating channels in wheelpaths. It is caused by traffic compaction ordisplacement of unstable material.Severe rutting (over 2”) may be causedby base or subgrade consolidation.Repair minor rutting with microsurfacingor overlays. Severe rutting requiresmilling the old surface or reconstructingthe pavement before resurfacing. Baseor subgrade improvement may benecessary if rutting is related to poorbase or subgrade conditions.

AC 150/5320-17 Appendix 1 7/12/04

Even slightrutting isevidentafter a rain.

Severe ruttingover 2” causedby poor mixdesign.

Severe ruttingcaused by poorbase orsubgrade.

▼

▼

▼

EVALUATION — Surface Deformation6

AC 150/5320-17 Appendix 1 7/12/04

DistortionShoving or rippling is the displacementof surfacing material. It can developwhen the asphalt mixture is unstablebecause of poor quality aggregate orimproper mix design. Repair by millingsmooth and overlaying with stableasphalt mix.

Other pavement distortions may becaused by settling, frost heave, etc.Patching may provide temporary repair.Permanent correction involves removalof unsuitable subgrade material andreconstruction.

Minorsettlementover sealedcrack.

▼

Heavy traffic hasshoved pavementinto washboardripples and bumps.▼

Frost heavedamage from springbreak-up.

▼

Severesettlementof patch.

▼

Significant settlement(over 2”) and crackingadjacent to sealed crack.▼

Severe settlingfrom utility trench.

▼

AC 150/5320-17 Appendix 1 7/12/04EVALUATION — Cracks 7

CRACKS

Thermal cracksThermal cracks are often regularlyspaced. The cause is movement due totemperature changes and hardeningof the asphalt with aging.

Thermal cracks will initially bewidely spaced (several hundred feetapart). Additional cracking will occurwith aging until they are closelyspaced (within several feet). Theseusually begin as hairline or very narrowcracks; with aging they widen. If notproperly sealed and maintained,secondary or multiple cracks developparallel to the initial crack. The crackedges can further deteriorate byraveling and eroding the adjacentpavement.

Help prevent water intrusion anddamage by sealing cracks as soon asthey appear. Routing and cleaning thecrack will improve the performance of crack sealant.

Differential thermal stress can alsocause cracking. Pavement markingpaint and sealcoats using materialswith significantly different thermal

Water enters unsealedcracks softeningpavement and causingsecondary cracks.

Open crack – 1⁄2” or more in width.

Pavement ravels and erodesalong open cracks causingdeterioration.

Tight cracks lessthan 1/4” in width.

▼ ▼ ▼ ▼

Widely spaced,well-sealed cracks.

▼

Failed sealant.

▼

Pavement marking maycause thermal stress andlead to surface cracking.▼

Sealed cracks, someclosely spaced.

▼

Severe thermalcracking in coaltar sealant.

▼

EVALUATION — Cracks8

AC 150/5320-17 Appendix 1 7/12/04

properties can create surface cracking.

Reflection cracksCracks in overlays reflect the crackpattern in the pavement underneath.They are caused by movement in theunderlying pavement due to tempera-ture change. This movement createsvery large stress in the overlay.Therefore, they are difficult to preventand correct.

Slippage cracksCrescent or rounded cracks caused by slippage between an overlay and an underlying pavement. Slippage is most likely to occur at locations where traffic is stopping and starting.Repair by removing the top surface and resurfacing using a tack coat.

Cracksreflectedthrough

bituminousoverlay.

Hairline cracksreflected through

sealcoat.

Loss of bond between pavementlayers allows traffic to break loosepieces of surface.

▼

▼

▼

EVALUATION — Cracks 9

AC 150/5320-17 Appendix 1 7/12/04

Paving joint and edge cracksPaving joint cracks are caused by inade-quate bonding and poor compaction ofthe joint during construction. They mayalso be caused by reflection of poorjoints in the underlying pavement.Cracks within one foot of the edge arecaused by insufficient shoulder support,poor drainage, or frost action. Cracks usually start as hairline or very narrow,widening and eroding with age. With-out crack filling, they can ravel, developmultiple cracks, and become wideenough to require patching.

Sealing cracks will help reducemoisture penetration and preventfurther subgrade weakening.

Paving joints. Slight crack onjoint near center. Open jointon right side.

Severecracking

and edgedistress.

First stage of wheelpathcracking causedby heavy trafficloads.

▼▼

Edge cracking in asphalt alongconcrete slab.

▼

▼

Partially open 1⁄4” paving joint.▼


AC 150/5320-17 Appendix 1 7/12/04

Block cracks

Block cracking is interconnected cracksforming large blocks. Cracks usually intersectat nearly right angles. Blocks may rangefrom one foot to approximately 10’ or moreacross. The closer spacing indicates moreadvanced aging caused by shrinking andhardening of the asphalt over time. Applysurface treatments during early stages toreduce weathering of the asphalt caused byexposure to the sun, moisture and freezing.Overlay or reconstruction is required in theadvanced stages.

Right angle cracking forms blocks.

Large blockswith open cracksfilled with grass.

▼

▼

Small blockswith open

cracks.

▼


AC 150/5320-17 Appendix 1 7/12/04

Alligator cracks

Interconnected cracks forming smallpieces ranging in size from about 1” to 6”. This is caused by failure of theentire pavement due to traffic loading(fatigue) and usually due to inadequatebase or subgrade support. Repair byexcavating and replacing failed sub-grade base and surface. Large areasrequire reconstruction. Improvements in drainage may often be required.

Alligator crackpattern. Tight cracksand one patch.

Alligator crackingnear pavementedge.

Alligator crackingand pothole.

▼▼

▼

EVALUATION — Patches and Potholes12

AC 150/5320-17 Appendix 1 7/12/04

PATCHES AND POTHOLES

PatchesOriginal surface repaired with newasphalt patch material. Indicates apavement defect or utility excavationwhich has been repaired. Patches withcracking, settlement or distortionsindicate underlying causes remain.Repair or reconstruction are requiredwhen extensive patching shows distress.

Typical repair ofutility excavation.

Patch in goodcondition.

Patchedarea in

poorcondition.

Overlay repair with edge raveling

and cracks.

▼

▼

▼

EVALUATION — Patches and Potholes 13

AC 150/5320-17 Appendix 1 7/12/04

Potholes

Holes and loss of pavementmaterial are caused by trafficloading, fatigue and inadequatestrength. Often combined withpoor drainage, this can createdangerous pavement debris.Repair by excavating orrebuilding localized potholes.Reconstruction required forextensive defects.

Completepavementfailure.

Large potholeand dangerousloose debris.

Shallowpothole.

▼

▼

▼

With an understanding of surfacedistress, you can evaluate and rateasphalt pavement surfaces. The ratingscale ranges from 5–excellent conditionto 1–failed. Most pavements will deteri-orate through the phases listed in therating scale. The time it takes to gofrom excellent condition (5) to completefailure (1) depends largely on the qualityof original construction, age, and theamount of heavy traffic loading.

Once significant deterioration begins,it is common to see pavement declinerapidly. This is usually due to a combina-tion of loading and the effects of addi-tional moisture. As a pavement agesand additional cracking develops, moremoisture can enter the pavement andaccelerate the rate of deterioration.

14

AC 150/5320-17 Appendix 1 7/12/04

Rating pavement surface condition

Rating 5 – ExcellentNo maintenance required

Rating 4 – GoodMinor routine maintenance, crack sealing

Rating 3 – FairPreservative treatments, crack sealingand surface treatment

Rating 2 – PoorStructural improvement and leveling (patching then overlay)

Rating 1 – FailedReconstruction

Rating system

Surfacerating

Visible distress* General condition/treatment measures

None, or initial thermal cracks, all narrow (less than 1⁄8”)5Excellent

Additional thermal cracking. Cracks generally spaced morethan 50’ apart. Less than 10% of cracks and joints needsealing. Minimal or slight raveling. No distortion. Patches ingood condition.

4Good

Moderate raveling. Thermal cracks and joints generallyspaced less than 50’ apart. Crack sealing or repair of sealantneeded on 10%-25% of cracks or joints. Edge cracks along10% or less of pavement edges. Block crack pattern withcracks 6’-10’ apart. Isolated alligator cracking and poorpatches. Minor distortion or crack settlement less than 1”.

3Fair

Frequent thermal cracks. Wide cracks and joints with ravelingin cracks. Deterioration along more than 25% of cracks. Edgecracks on up to 25% of pavement edges. Block cracks spaced5’ apart or less. Alligator cracking or poor patches cover up to 20% of surface area. Distortion or settlement 1“-2”.

2Poor

Widespread, severe cracking with raveling and deterioration.Alligator cracking and potholes over 20% of the area.Distortion over 2”.

New pavement less than 5 years old.No maintenance or isolated cracksealing required.

Recent sealcoat or pavement over 5 years old. Seal open cracks orjoints and replace sealant whereneeded.

Seal open cracks and joints. Replacefailed sealant. Apply new surfacetreatment or thin overlay. Minorpatching and joint repair.

Needs significant crack sealing pluspatching and repair on up to 25%of pavement surface. Overlay entirearea with structural overlay.

Condition may be limiting service. Needs reconstruction.1

Failed

* A given pavement segment may only have one or two types of distess rather than all of the types listed for a particular rating.

Look at the photographs whichfollow and become familiar with thedescriptions of the individual ratingcategories. To evaluate an individualpavement segment, first determine itsgeneral condition. Is it relatively new,toward the top end of the scale? In verypoor condition and at the bottom of thescale? Or somewhere in between? Next,think generally about the appropriatemaintenance method. Use the outlinedrating categories.

Finally, review the individual pave-ment distress and select the appropriatesurface rating. A given pavement willlikely not have all of the types ofdistress listed for any particular rating. Itmay have only one or two types.

In addition to indicating the surfacecondition of a pavement, a given ratingalso includes a recommendation forneeded maintenance or repair. Thisfeature of the rating system facilitates itsuse and enhances its value as a tool inongoing airfield pavement maintenance.


RATING 5

EXCELLENT — No maintenancerequired or isolatedcrack sealing.

New pavement less than 5years old. No visible distressor initial thermal cracks, allless than 1⁄8”.

Newpavement.

▼

Recent overlay.Sealed joint.▼

AC 150/5320-17 Appendix 1 7/12/04

Rating pavement surface condition16

AC 150/5320-17 Appendix 1 7/12/04

RATING 4

GOOD — Seal open cracks or joints.

Recent sealcoat or pavement over 5 years old. Additional thermalcracking. Cracks spaced 10’-20’ apart. Open cracks and joints needsealing on less than 10% ofcracks. No distortion and patchesin good condition.

Recentsealcoat.

▼

▼

Cracks sealed.No distortion.

Slight raveling.▼

Pavement more than 5 years old. Nopatches or distortion. Schedule routing

and sealing for isolated open joints.


AC 150/5320-17 Appendix 1 7/12/04

Cracks widelyspaced andsealed.

▼

Joints wouldbenefit fromsealing.▼

▼

Old sealant is leaking. Needsreplacement at isolated locations.


AC 150/5320-17 Appendix 1 7/12/04

RATING 3

FAIR —Seal open cracks and joints. Apply new surface treatmentor thin overlay. Minor patchingand joint repair.

Moderate raveling. Thermal cracksand joints, generally spaced lessthan 50’ apart. Crack sealing orrepair of sealant needed on 10%-25% of cracks or joints. Edge cracks along 10% or less of pavement edges. Block crackpattern with block cracks 6’-10’apart. Isolated alligator cracking and poor patches. Minor distortionor crack settlement less than 1”.

Thermal cracksless than 10’apart. Slight

raveling.

Open cracksneed sealing.▼

▼

Several patches ingood condition.

▼

Worn sealcoatneeds new

surfacetreatment.

▼


AC 150/5320-17 Appendix 1 7/12/04

Moderate raveling.Joint needs sealing.

▼

Pavementsettlement at crack less than 1” deep.

▼

Moderateraveling. Needs surfacetreatmentsoon.

▼

Edgecrackingat severallocations.

▼

Joint sealant needs replacement at several locations. Follow with new surface treatment on apron.

▼


AC 150/5320-17 Appendix 1 7/12/04

RATING 2

POOR — Needs significant crack seal-ing plus patching and repairon up to 25% of pavementsurface. Use structural over-lay over entire area.

Frequent thermal cracks. Widecracks and joints with raveling incracks. Deterioration along morethan 25% of cracks. Edge cracks on up to 25% of pavementedges. Block cracks spaced 5’apart or less. Alligator cracking orpoor patches cover up to 20% ofsurface area. Distortion or settle-ment 1”-2”.

▼

▼

▼▼▼

Severeraveling.

Wide crackswith nosealant.

Multiple cracks open and deteriorated

Numerous cracks withsettlement over 1”.

▼

Block crackingwith cracks lessthan 5’ apart.

▼

Patch in poor

condition.


AC 150/5320-17 Appendix 1 7/12/04

Needs overlay.

▼

More than 25% of crack sealantneeds replacement. Minorsettlement over cracking.

▼

Sealant repair needed onmore than 25% of cracks.

▼

Edgecrackingon up to25% of thepavement.

▼

Repair broken pavementand apply overlay.

▼


AC 150/5320-17 Appendix 1 7/12/04

RATING 1

FAILED — Condition may be limiting service. Needs reconstruction.

Widespread, severe cracking withraveling and deterioration. Alligatorcracking and potholes over 20% ofthe area. Distortion over 2”

▼

▼

▼

Over 25% alligatorcracking.

Severecracking anddeterioration.

Extensive alligatorcracking. Poor patches.

▼

Failed patch.Settlementover 2”.

▼

Extensive failedpavement

and debris.

23

Inventory and field inspection

Most airport owners routinely observepavement conditions as a part of theirnormal work. However, an actualinspection means looking at the entiresystem as a whole and preparing awritten summary of conditions. Thisinspection has many benefits overcasual observations. It can be helpful to compare pavement features as awhole system so ratings andmaintenance decisions can be moreconsistent.

An inspection also encourages a reviewof specific conditions important inpavement maintenance, such asdrainage, adequate strength, and safety.

A simple written inventory is useful in making decisions where other peopleare involved. You do not have to trustyour memory, and you can usuallyanswer questions in more detail. Havinga written record and objective informa-tion also improves your credibility withthe funding agencies.

Finally, a written inventory is veryuseful in documenting changing pave-ment conditions. Without records overseveral years, it is difficult to know ifconditions are improving, holding theirown, or declining.

A sample inventory form is shown onthe inside back cover. It is very helpfulto collect background information oneach feature. Pavement thickness, age,and major maintenance are examples ofhelpful information.

Annual budgets and long rangeplanning are best done when based onactual needs as documented with awritten inventory.

Pavement features

Inventory and pavement condition dataare normally organized by dividing thepavements into segments or features.

A plan or aerial photo of the entireairfield is most helpful in identifyingthese individual features. Runways,taxiways and aprons should beconsidered as separate categories.Within each category, the pavementshould be separated into features withsimilar construction. For example,pavements with different thickness,age, or type of construction should berated separately.

A runway may be all one feature ifconditions are similar. However, if partsof the runway have significantly differ-ent construction details or condition,then separate features will make therating more logical and useful.

Each taxiway, can be considered aseparate feature. You may combineseveral sections of taxiway if conditionsare similar.

Apron areas can be separated intofeatures according to the areas theyserve. For example, aprons serving aterminal, hangers, tie-down area, orfueling area would be separatefeatures. Areas in different conditionsmay also be separated into features.

Averaging and comparing sections

No pavement feature is entirelyconsistent. Also surfaces in one sectionmay not have all of the types of distresslisted for any particular rating. Theymay have only one or two types.

The objective is to rate the conditionthat represents the majority of thepavement feature. Small or isolatedconditions should not influence therating. It is useful to note these specialconditions on the inventory form sothis information can be used in plan-ning specific improvement projects. For example, some spot repairs may be required.

Occasionally surface conditions vary

significantly within a feature. Forexample, short sections of goodcondition may be followed by sectionsof poor surface conditions. In thesecases, it is best to rate the featureaccording to the worst conditions andnote the variation on the form.

The overall purpose of conditionrating is to be able to compare eachfeature relative to all the other featuresin your airport pavement system. Oncompletion you should be able to lookat any two pavement features and findthat the better surface has a higherrating.

Assessing drainage conditions

Moisture and poor pavement drainageare significant factors in pavementdeterioration. Some assessment ofdrainage conditions during pavementrating is highly recommended. Whileyou should review drainage in detail at the project level, at this stage simplyinclude an overview drainage evalu-ation at the same time as you evaluatesurface condition.

Consider both pavement surfacedrainage and lateral drainage (ditchesor storm sewers). Pavement should be able to quickly shed water off thesurface. Ditches should be large anddeep enough to drain the pavementand remove the surface water efficiently into adjacent waterways.

Look at the crown and check for low surface areas that permit ponding.Runways and taxiways should haveapproximately a 1.5% cross slope orcrown across the pavement. Apronareas require positive drainage andoften include storm drainage systems.Maintenance of the entire drainagesystem is critical. Ditches, subsurfacedrains and outlets should be inspectedand cleaned regularly.

Practical advice on rating airfield pavements

AC 150/5320-17 Appendix 1 7/12/04

technique. Consider future traffic projections,

original construction, and pavementstrength since these may dictate amore comprehensive rehabilitation thanthe rating suggests.

Summary

Using funds most efficiently requiresgood planning and accurate identifi-cation of appropriate rehabilitationprojects. Assessing pavementconditions is an essential first step inthis process. This asphalt pavementsurface condition rating procedure has

proven effective in improving decisionmaking and using funds moreefficiently. It can be used directly byairport staff and consultants. It may becombined with additional testing anddata collection in a more comprehensivepavement management system.

Practical advice on rating airfield pavement 24

AC 150/5320-17 Appendix 1 7/12/04

A pavement’s ability to carry heavytraffic loads depends on both thepavement materials (asphalt surfacingand granular base) and the strength ofthe underlying soils. Most soils losestrength when they are very wet.Therefore, it is important to providedrainage to the top layer of the subgrade supporting the pavementstructure.

Planning annual maintenance and repair budgets

We have found that relating a normalmaintenance or rehabilitation procedureto the surface rating scheme helpsmanagers use the rating system.However, an individual surface ratingshould not automatically dictate thefinal maintenance or rehabilitation

References

Concrete Aviation Airfields PASER Manual, 2003, Engineering ProfessionalDevelopment, College of Engineering, University of Wisconsin-Madison.

Guidelines and Procedures for Maintenance of Airport Pavements, 7/14/03,Federal Aviation Administration, Advisory Circular AC:150/5380-6A.

AC 150/5320-17 Appendix 1 7/12/04

AIRFIELD PAVEMENT INVENTORY

Airfield _______________________________________________________________ Condition survey date _________________________

Done by _____________________________________________________________________________________________________________________________________

Facility (runway, taxiway, apron) __________________________________________________________________________________________________________

Feature description _________________________________________________________________________________________________________________________

Feature location ____________________________________________________________________________________________________________________________

Feature area _________________________________________________________________________________________________________________________________

Construction date __________________________________________________________________________________________________________________________

Pavement type: ■■ Asphalt ■■ Concrete Layer thicknesses: ___________ ___________ ___________

Maintenance history __________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

PASER Rating ( 5 = Excellent, 4 = Good, 3 = Fair, 2 = Poor, 1 = Failed) ■■Comments on pavement and drainage conditions _______________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

Recommended maintenance ___________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

Recommended rehabilitation __________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

PASERAsphalt Airfield Pavements

AC 150/5320-17 Appendix 2 7/12/2004

APPENDIX 2--CONCRETE AIRFIELD PAVEMENT SURFACE EVALUATION AND RATING MANUAL


PASERManualConcrete Airfield Pavements

RATING5

RATING3

RATING1

This manual is intended to assist airfield managers in understandingand rating the surface condition of rigid Portland Cement Concrete(PCC) pavements. It describes types and causes of distress andprovides a simple system to visually rate pavement condition.

Produced for the Federal Aviation Administration by EngineeringProfessional Development, College of Engineering, University ofWisconsin-Madison.

Contents

Introduction 2

Evaluating pavement condition 3

Surface defects 4

Joints 6

Pavement cracks 7

Pavement distortion 10


Rating system 13

Rating 5 — Excellent 14

Rating 4 — Good 14

Rating 3 — Fair 15

Rating 2 — Poor 16

Rating 1 — Failed 17

Practical advice on rating roads 19

Airfield Pavement Inventory inside back cover

AC 150/5320-17 Appendix 2 7/12/04

Donald Walker, P.E., University of Wisconsin–Madison, author

Lynn Entine, Entine & Associates, editor

Susan Kummer, Artifax, designer

PASERManual


Concrete Airfield Pavements

AC 150/5320-17 Appendix 2 7/12/04

An airport manager’s goal is to use available funds to provide a safe andeconomical pavement surface. This is no simple task. It requires balancingpriorities and making difficult decisions in order to manage pavements. Thismanual offers useful information for planning maintenance and managingPortland Cement Concrete (PCC) pavements. It discusses common problemsand typical repairs and includes a visual system for evaluating and rating PCC pavements.

General aviation airfield pavements are often managed informally, based onthe staff’s judgment and experience. While this process is both important andfunctional, using a slightly more formalized technique can make it easier tomanage pavements effectively.

Experience has shown that there are three steps that are especially useful inmanaging airfield pavements:

1) Inventory all pavements.

2) Periodically evaluate the condition of all pavements.

3) Use the condition evaluations to set priorities for projects and evaluate alternative treatments.

A comprehensive pavement management system involves collecting dataand assessing several pavement characteristics: roughness, surface distress(condition), surface skid characteristics, drainage, and structure (pavementstrength and deflection). Planners can combine this condition data witheconomic analysis, to develop short-range and long-range plans for a varietyof budget levels. However, general aviation agencies may lack the resourcesfor such a full-scale system.

Since surface condition is the most vital element in any pavement manage-ment system, managers may use the simplified rating system presented in thisConcrete Airfield Pavements PASER Manual to evaluate their pavements. APASER Manual for asphalt airfield pavements is also available (see References,page 20).

PASER — Pavement Surface Evaluation and Rating

Concrete Airfield Pavements

AC 150/5320-17 Appendix 2 7/12/043

Rigid pavement performance

PCC pavements are either plain (non-reinforced) or reinforced concrete.Reinforcement is usually provided bysteel wire mesh placed approximately at mid-slab depth. The reinforcement is intended to limit crack opening andmovement in the concrete slab. Mostairfield pavements are not reinforced.

Since concrete slabs need to move(expand and contract) with changes intemperature and during initial cure(drying and shrinkage), pavements areconstructed with contraction joints.These are usually sawn into the pave-ment shortly after initial curing. Thisjoint gives the slab a place to crack andmakes a straight, well-formed groove to seal. Runways, taxiways and aprons(ramps) are sawn to create square slabsranging from 15’ to a maximum of 25’.

Isolation joints are occasionallyprovided. These are wider, full depth,and filled with a material to allowexpansion. If used, they are placedadjacent to structures that cannot movewith the pavement such as buildings,manholes, and other utility structures.These isolation joints are also used atpavement intersections and allowchanges in joint patterns.

Rigid, PCC pavements carry trafficloadings differently than flexiblepavements (asphalt). Concrete pave-ments are designed to act like a beamand use the bending strength of theslabs to carry the load. Therefore, loadtransfer across cracks and joints isimportant, especially on pavements with heavy traffic loading. Hairline andnarrow cracks still have interlockedconcrete aggregate and can effectivelytransfer loads. Because wide cracks and widely-spaced joints open up, theycannot transfer loads and must take

Evaluating pavement condition

higher edge loads. These higher edgeloads can cause further cracking anddeterioration along the joint, or crackedges.

Many concrete pavements usejoints that have load transfer dowels.These are smooth steel bars placedacross the joint. They transfer trafficloads between adjacent concrete slabs while allowing the joint to openand close. These bars can rust andsometimes cause problems. Thecorrosion causes forces on theconcrete which leads to spalling,cracking, and general joint deterior-ation. Epoxy coated dowels may beused to reduce corrosion.

Unsupported slab edges will deflector bend under a load. If the support-ing soil is saturated it can squirt upthrough joints or cracks when theslab bends. This is called pumping.Eventually the loss of supporting soilthrough pumping creates an emptyspace or void under the slab. Theslabs may then crack further underloads and joints will deteriorate more.

Undoweled joints under heavytraffic may fault. This is when oneslab edge is lower than the next slab.Faulting is more likely on pavementswith most of the traffic in one direction. The downstream traffic slabwill be lower than the upstream slab,creating a step. Faulting creates arough pavement.

You can often detect pumping bythe soil stains around pavement jointsor cracks. The resulting voids can begrouted full or sub-sealed. Slabs canbe leveled by slab jacking or mudjacking. Obviously, sealing cracks andjoints and improving subsoil drainagewill help reduce pumping, faulting,and joint failures.

PCC pavement conditions and defects

It is helpful to separate various condi-tions common to PCC pavements.These are described individually insome detail. We include causes fordeterioration and common strategiesfor repair. Some defects are localizedwhile others indicate that problemsmay develop throughout the pave-ment. It is important to distinguishbetween local and widespread defects.Assessing the conditions of actualpavements also involves looking forcombinations of these individualdefects.

There are four major categories ofcommon PCC pavement surfacedistress and condition:

Surface defectsPolishing, map cracking, pop-outs,scaling, spalling.

Joints Longitudinal and transverse joints.

Pavement cracksSlab cracks, D-cracking, cornercracks, meander cracks, manhole and inlet cracking.

Pavement distortion Pavement settlement or heave;blow ups; faulting; utility repairs,patches and potholes.

In reviewing the different defects it is important to consider both theirseverity and extent. Generally, condi-tions begin slowly and progressivelybecome more serious. Slight defectsmay grow into moderate and thensevere conditions. In addition, defectsmight initially be indicated only in afew isolated cases. Examples in therating section will help identify howbad and how extensive a condition is.

EVALUATION — Surface Defects4

AC 150/5320-17 Appendix 2 7/12/04

SURFACE DEFECTS

PolishingA worn or polished surface maydevelop from traffic wearing off thesurface mortar and skid-resistanttexture. An asphalt overlay orgrinding the concrete surface can restore skid resistance.

Map crackingA pattern of fine cracks usually spaced within several inches is calledmap cracking. It usually developsinto square or other geometricalpatterns. Map cracking can becaused by improper cure or over-working the surface during finishing.It may also indicate a problem withthe quality of the aggregate knownas ASR (alkali-silica reactivity). Ifsevere, cracks may spall or thesurface may scale. Repair is usuallylimited to very severe conditions. An asphalt overlay or partial depthpatching may then be necessary.

Pop-outsIndividual pieces of large aggregatemay pop out of the surface. This isoften caused by chert or otherabsorbent aggregates that deterio-rate under freeze-thaw conditions.Pop-outs alone do not usually affectpavement serviceability. However,damage to aircraft from the debrismay occur. For severe areas, apatch, overlay or slab replacementmay be necessary.

▼▼

Extensivepop-outs of large

aggregatefrom surface.

Severalpop-outsin a new

slab.

▼

Map crackinghas hairline

surface cracks,probably

shallow indepth. May

not cause anylong-term

performanceproblems.

▼

Close-up of a polishedpavement surface.

EVALUATION — Surface Defects 5

ScalingScaling is surface deterioration thatcauses loss of fine aggregate andmortar. More extensive scaling canresult in loss of large aggregate. Thecause often is using concrete which has not been air-entrained, making the surface susceptible to freeze-thawdamage.

Scaling can occur as a general conditionover a large area or be isolated tolocations where poor quality concrete orimproper finishing techniques causedloss of entrained air. In severe cases,deterioration can extend deep into theconcrete. Debris from scaling candamage aircraft.

Grinding may remove poor qualitysurface concrete. Partial depth patchingof isolated areas may also prolong thelife of the pavement. Severe scaling mayrequire slab replacement.

SpallingSpalling is the loss of a piece of theconcrete pavement from the surface oralong the edges of cracks and joints.Cracking or freeze-thaw action maybreak the concrete loose, or spallingmay be caused by poor quality mate-rials. Spalling may be limited to smallpieces in isolated areas or be quite deep and extensive. Large pieces ofloose concrete can cause seriousdamage to aircraft.

Repair will depend on the cause. Smallspalled areas are often patched. Spallingat joints may require full depth jointrepair or full slab replacement.

AC 150/5320-17 Appendix 2 7/12/04

Slight scaling.Minor loss ofsurface mortar.

Moderate surfacescaling. Loss of

mortar and finesstarting to exposelarger aggregate.

Severescaling.Some largeraggregate isloose.

▼ ▼

▼

Smallsurface spallthat hasbeenpatched.

▼

Spall at crack.Createsdangerousdebris.

▼

Spallingalong a joint.

▼

EVALUATION — Joints6

AC 150/5320-17 Appendix 2 7/12/04

JOINTS

Construction joints or sawn joints are narrow and usually well sealed. As pavements age and materialsdeteriorate, joints may open wider anddeteriorate further. Cracks parallel to theinitial joint may develop and accelerateinto spalling or raveling. Settlement,instability, or pumping of subgrade soilcan cause joints to fault. One commoncause of cracks parallel to joints iswaiting too long after the pour to sawthe joint. Then, during initial cure theslab will crack near the sawn joint.

Maintaining a tight joint seal canprevent intrusion of water and debrisand reduce freeze-thaw damage andpumping. Debris may accumulate inopen joints which prevents normal joint movement. This will greatlyaccelerate joint deterioration. Severejoint deterioration may require full depth patching and joint replacement.

Taxiway withspalled joint.

Joint sealant in poorcondition. Loss ofbond to edge allowswater into pavement.

New pavement with good joints.

▼

Joint sealant deterioration on apron.Slab is in good condition.

▼

▼

Severe spallingalong joint andcrack. Creates debris.

▼

▼

AC 150/5320-17 Appendix 2 7/12/04EVALUATION — Cracks 7

PAVEMENT CRACKS

Slab cracksSlab cracks divide the slab into 2 ormore pieces. They can be caused bythermal stresses, poor subgrade support,or heavy loadings. They are sometimesrelated to slabs with joints spaced toowidely. Slabs with a length-to-width ratiogreater than 1.25 are more likely todevelop mid-slab cracks.

As with joints, these cracks may deteri-orate further if not sealed well. Slabs can fault at cracks. Cracks can spall and develop additional parallel cracking.Severe deterioration may requirepatching individual cracks. Multipletransverse cracks in individual slabsindicate further deterioration. Extensiveslab cracking indicates pavement failureand the need for complete replacement.

Crack next to joint oftencaused by late sawing. Crackshows early signs of spalling.

Hairline slab crack.Tight with no spalling.

▼

▼

Slab crack with grass,no sealant, and spallsdeveloping.

▼ ▼

Slab crackwith spallingand debris.

▼

Multiple slab cracksand broken pavement.Replacement needed.

▼

Closely spaced, hair-line,transverse cracks indicate slabis broken and needs replacing.

▼


AC 150/5320-17 Appendix 2 7/12/04

D-cracksOccasionally, severe deterioration maydevelop from poor quality aggregate. So called D-cracks or disintegrationcracking, develop when the aggregate is able to absorb moisture. This causes the aggregate to break apartunder freeze-thaw action which leads to deterioration. Usually, it starts at thebottom of the slab and moves upward.

Fine cracking and a dark discolorationadjacent to the joint often indicate a D-cracking problem. Once this is visible on the surface the pavement material is usually severely deteriorated andcomplete replacement is required.

Joint or crack sealing helps slow D-cracking deterioration. This is a seriousdefect because it may indicate a materialquality problem throughout the pave-ment. Milling and patching has provensuccessful as a short term repair.

Corner cracksDiagonal cracks may develop near thecorner of a concrete slab, forming atriangle with the joint. Usually thesecracks are within a foot or two of theslab corner and are caused by insufficientsoil support or concentrated stress due totemperature-related slab movement. Thecorner breaks under traffic loading. Theymay begin as hairline cracks.

Some corner cracks extend the full depth of the slab while others start at the surface and angle down toward the joint.With further deterioration, more crackingdevelops, and eventually the entirebroken area may come loose. This maybe a localized failure, but it oftenindicates widespread maintenanceproblems.

Partial or full depth concrete patching or full depth joint replacement may beneeded when corner cracking isextensive.

Surface discoloration near jointsand cracks indicates D-crackingand severe slab deterioration.

Multiple crackpatterns adjacent

to joints. Common D-cracking pattern.

▼

Corner cracking inall four slabs.

▼

Cornercracking

withslight

spalling.

▼

Cornercracking,

severespalling,

anddangerous

debris.

▼

▼ ▼


AC 150/5320-17 Appendix 2 7/12/04

Meander cracksSome pavement cracks appear towander randomly. They may cross a slab diagonally or meander in a randommanner. Meander cracks may be causedby settlement due to unstable subsoil ordrainage problems. Frost heave andspring thaw can also cause them. Theyare often local in nature and may notindicate general pavement problems.

Minor cracks may benefit from sealingto minimize water intrusion. Extensive or severe meander cracks may requirereplacing the slab, stabilizing thesubsurface, or improving drainage.

Manhole and inlet cracksThe pavement adjacent to a light can,manhole, or storm sewer inlet oftencannot accommodate normal pavementmovement due to frost heaving andtemperature changes. Cracks andfaulting may develop and the concreteslab may deteriorate further. These areoften localized design defects that maynot indicate a general pavementproblem. Sealing and patching may slowthe deterioration. Eventually full depthrepairs may be required.

Inlet with severecracking and

spalling. Full depthslab repair required.

▼

Slabs replaced next toinlet. Good joint design.

▼Meandercrack causedby settlement.Lack ofmaintenanceallows waterto intrude and debris to collect in crack.

▼Faulting andspalling of ameandercrack.

▼

Two spalls at manhole in anew pavement. Partial depthpatching would be beneficial.▼

PAVEMENT DISTORTION

Pavement settling or heaveUnstable or poorly drained subgradesoils may cause pavements to settle afterconstruction. Poorly compacted utilitytrenches may also settle. This may be agentle swale or a fairly severe dip.

Frost-susceptible soils and high watertables can cause pavements to heaveduring the winter months. Extensivepavement cracking and loss of strengthduring the spring can result in severedeterioration. Improved drainage andstabilization of subgrade soils is usuallynecessary, along with pavementreconstruction.

BlowupsConcrete slabs may push up or becrushed at a joint. This is caused byexpansion of the concrete whereincompressible materials (sand, debris,etc.) have infiltrated into poorly sealedjoints. As a result, there is no space toaccommodate expansion. It is morecommon in older pavements with longjoint spacing. Pavements that haveaggregate susceptible to ASR mayexperience more frequent blowups.Pressure relief joints can be installed and blowup areas must be patched orreconstructed. Cleaning and sealingjoints will help prevent blowups.

Internal pressure has partially raised slab atthe joint. Complete replacement is required.

Settlement causedmeander crackwith faulting.

▼

Extensive cracking and patchingcaused by settlement. Pavement wasbuilt on unstable sub-grade soils. ▼

Pavement blowup in progress—concrete is crushed and slab buckled.

▼

▼

EVALUATION — Distortion10

AC 150/5320-17 Appendix 2 7/12/04

EVALUATION — Distortion 11

AC 150/5320-17 Appendix 2 7/12/04

FaultingJoints and cracks may fault or develop astep between adjacent slabs. Faulting iscaused by pumping of subgrade soilsand creation of voids. Heavy traffic canrapidly accelerate faulting. Joints mayfault due to settlement of an adjacentslab.

Faulting creates a rough pavement andmay cause slab deterioration. Minorfaulting can be corrected by surfacegrinding. Voids can be subsealed, orslabs can be mud jacked back to levelposition. Severe cases may need joint orslab replacement.

Faulting of joints.Aggravated by heavytraffic in one direction.Could improve surfaceby grinding.

▼

Severe joint faultand spalling.

Severe joint fault.

▼

▼

EVALUATION — Distortion12

AC 150/5320-17 Appendix 2 7/12/04

Utility repairs, patchesand potholesSlab replacement or repair of utilities will require cuts and slab patching.Patches from previous repairs mayperform like original pavement or mayshow settlement, joint deterioration or distress.

Localized failures of materials orsubgrade soil can cause individualpotholes. Surface spalling or othermaterial defects may develop intolocalized potholes. Full depth patchingor slab replacement is usually required.

Full depth jointrepair. Very good

condition.

▼

Partial depthconcrete patch

to repair cornercracks. Good

condition.

Joint repair with asphalt.Very good condition.

▼

Potholes causedby severe jointdeterioration.

Need repair.▼

Asphalt patches. Poor (top)and fair (bottom) condition.

▼▼

13

AC 150/5320-17 Appendix 2 7/12/04

Using your understanding of pavementconditions and distress, you can evalu-ate and rate airfield PCC pavements.The rating scale ranges from5–excellent condition to 1–very pooror failed. Some pavements will deteri-orate through the phases listed in therating scale. The time it takes to gofrom an excellent (5) to failed condition(1) depends largely on the quality of theoriginal construction, age, and theamount of heavy traffic loading.

Once significant deterioration begins,it is common to see pavements deteri-orate rapidly. This is usually due to thecombined effects of loading and addi-tional moisture. As a pavement agesand additional cracks develop, moremoisture can enter and accelerate therate of deterioration.

Rating system

Rating pavement surface condition

Surfacerating

Visible distress* General condition/treatment measures

None.5Excellent

Hairline or sealed cracks 1⁄8” wide or less. Map cracking. Pop-outs.4

Good

Several slabs broken into two pieces by slab cracks. Cornercracking on several slabs, 1⁄4” wide with no spalling. Jointsealant mostly in good condition, less than 10% needingreplacement. Several patches in fair to good condition. Map cracking or scaling on 10% or less of the surface area.Slight faulting, less than 1⁄4”, in several locations.

3Fair

Many slab cracks, some breaking the slab into three or more pieces. Cracks open 1⁄8” or cracks with spalling. D-cracks at several joints. Sealant failure over 10% of joints.Several patches in fair to poor condition with cracks in patchand uneven surface. Faulting 1⁄4” to 1⁄2” in several locations.Severe or extensive scaling.

2Poor

Many wide cracks with failed sealant and grass. Extensive crack and joint spalling. Slabs extensively cracked or shattered. Many corner breaks with spalling.D-cracks with spalling. Patches in poor condition withspalling. Numerous faults over 1⁄ 2”.

New pavement or recent major concreterehabilitation. Like-new condition. Less than5 years old. No maintenance required.

Concrete over 5 years old. Signs of wear.Minor spot repair of cracks or joint sealant.

First sign of significant slab cracking, corner cracking, scaling, or faulting. Several patches. Joint sealant repairrequired. Isolated repair of joint or patch.

Needs sealant replacement on more than10% of cracks or joints. Partial depth or fulldepth joint repairs or patch replacement.Repair faulted joints. Replace or overlayslabs with severe scaling. Bonded or unbonded concrete overlay.

Extensive full depth joint repairs or slabreplacements. Extensive patching andcomplete overlay. Complete reconstruction.1

Failed

* A given pavement segment may not have all of the types of distress listed for a particular rating. It may have only one or two types.

Look at the photographs whichfollow and become familiar with thedescriptions of the individual ratingcategories. To evaluate an individualpavement, first determine its generalcondition. Is it relatively new, toward thetop end of the scale? In very poorcondition and at the bottom of thescale? Or somewhere in between? Next,think generally about the appropriatemaintenance method.

Finally, review the individualpavement condition and distress andselect the appropriate pavement surfacerating. Individual pavements may nothave all of the types of distress listed forany particular rating. They may haveonly one or two types. Use thecategories in the rating table below.

Each rating also includes a recommen-dation for needed maintenance or repair.This makes the rating system easier to use and enhances its value as a tool inongoing airfield pavement maintenance.

Rating 5 – ExcellentNo maintenance required.

Rating 4 – GoodMinor routine maintenance, crack or joint sealing.

Rating 3 – FairMore crack or joint sealing. Isolated joint repairs or slab patching.

Rating 2 – PoorExtensive crack or joint sealing. Repair severe joint deterioration. Partial and full-depth slab repairs.

Rating 1 – FailedReconstruction.


AC 150/5320-17 Appendix 2 7/12/04

RATING 5

EXCELLENT — No maintenance required

Rating 5 is for new pavementor for recent major concreterehabilitation. Like-newcondition. Less than 5 years old.No maintenance required.

New or like-new

pavementcondition.

▼

▼

RATING 4

GOOD — Little or no maintenance required

Minor spot repair of cracks orjoint sealing required. PCCpavement over 5 years old.Signs of wear: hairline or sealedcracks 1⁄8” wide or less, mapcracking, pop-outs.

Surfacewear andpop-outs.

Partial loss of joint sealant.

▼

Map cracking,but pavementis sound.

Isolatedmeander crack,tight and wellsealed.

▼

▼


RATING 3

FAIR — First sign of significant slab cracking, corner cracking, scaling, or faulting. Several patches.Joint sealant repair required. Isolated repair of joint or patch.

Several slabs broken into two pieces byslab cracks. Corner cracking on severalslabs, 1⁄4” wide with no spalling. Jointsealant mostly in good condition, less than 10% needing replacement. Severalpatches in fair to good condition. Mapcracking or scaling on 10% or less of the surface area. Slight faulting, less than1⁄4”, in several locations.

Crack breaks slab into twopieces. Well sealed.

Crackbreaks off largecorner of slab.

▼

Crackparallel tojoint. Open1⁄4”. Nospalling.

▼

▼

Severe scaling. Joint andsealant in fair condition.

▼

Isolated spallat manhole.

▼

Moderatescaling.

▼

AC 150/5320-17 Appendix 2 7/12/04


AC 150/5320-17 Appendix 2 7/12/04

RATING 2

POOR —Cracks open 1/8”, D-cracks at joints. Replacesealant, repair joints.

Many slab cracks, some breakingthe slab into three or more pieces.Cracks open 1/8” or cracks withspalling. D-cracks at several joints.Sealant failure over 10% of joints.Several patches in fair to poorcondition with cracks in patch anduneven surface. Faulting 1/4” to1/2” in several locations. Severeor extensive scaling.

Open jointwith

spalling.

Corner cracks with spalling.Full depth patch required.

Open cracks with edgespalling. Corner crackand broken corner piece.

Open joints and cracks.Need sealant on morethan 10% of joints.

Full depth jointrepair required.

▼

Concrete patch inpoor condition.

▼

▼

▼

▼

Faulting of joints aggravated byheavy traffic in one direction.

▼

▼


AC 150/5320-17 Appendix 2 7/12/04

▼

Severe joint faultand spalling.

▼

RATING 1

FAILED — Extensive repairs, overlay, or complete reconstructionnecessary.

Many wide cracks with failed sealant andgrass. Extensive crack and joint spalling.Slabs extensively cracked or shattered.Many corner breaks with spalling. D-cracks with spalling. Patches in poorcondition with spalling. Numerous faultsover 1⁄ 2”. Extensive full depth jointrepairs or slab replacements, extensivepatching and complete overlay, orcomplete reconstruction needed.

Multiple slab cracks,spalling andshattered slabs.

Failed joint withsevere spallingand pothole.

▼

▼

Inlet with severe crackingand spalling. Full depthslab repair required.


AC 150/5320-17 Appendix 2 7/12/04

RATING 1

FAILED (continued)

Severe scaling overextensive areas.

Reconstructionrequired.

▼

Closelyspaced cracks

and poorjoint.

Reconstruct.

▼

Severedeterioration.

Requiresreconstruction.

▼

19

AC 150/5320-17 Appendix 2 7/12/04

Inventory and field inspection

Most airport owners routinely observepavement conditions as a part of theirnormal work. However, an actualinspection means looking at the entiresystem as a whole and preparing awritten summary of conditions. Thisinspection has many benefits over casual observations. It can be helpful tocompare pavement features, and ratingsdecisions are likely to be more consistentbecause the system is considered as awhole within a relatively short time.

An inspection also encourages areview of specific conditions importantin pavement maintenance, such asdrainage, adequate strength, and safety.

A simple written inventory is useful in making decisions where other peopleare involved. You do not have to trustyour memory, and you can usuallyanswer questions in more detail. Havinga written record and objective informa-tion also improves your credibility withthe funding agencies.

Finally, a written inventory is veryuseful in documenting changing pave-ment conditions. Without records overseveral years, it is more difficult to knowif conditions are improving, holding theirown, or declining.

A sample inventory form is shown onthe inside back cover. It is very helpful to collect background information oneach feature. Pavement thickness, age,and major maintenance are examples of helpful information.

Annual budgets and long rangeplanning are best done when based onactual needs as documented with awritten inventory.

Pavement features

Inventory and pavement condition dataare normally organized by dividing thepavements into segments or features. Aplan or aerial photo of the entire airfieldis most helpful in identifying these

individual features. Runways, taxiwaysand aprons should be considered asseparate categories. Within eachcategory, the pavement should beseparated into features with similarconstruction. For example, pavementswith different thickness, age, or type ofconstruction should be rated separately.

A runway may be all one feature ifconditions are similar. However, if partsof the runway have significantly differ-ent construction details or condition,then separate features will make therating more logical and useful.

Each taxiway, can be considered aseparate feature. You may combineseveral sections of taxiway if conditionsare similar.

Apron areas can be separated intofeatures according to the areas theyserve. For example, aprons serving aterminal, hangers, tie-down area, orfueling area would be separatefeatures. Areas in different conditionsmay also be separated into features.

It is helpful to note the size of slabsor panels as well as the number ofslabs in a feature. The overall area can be calculated and used to preparemaintenance or construction estimates.

Averaging and comparing sections

No pavement feature is entirelyconsistent. Also surfaces in one sectionmay not have all of the types of distresslisted for any particular rating. Theymay have only one or two types.

The objective is to rate the conditionthat represents the majority of thepavement feature. Small or isolatedconditions should not influence therating. It is useful to note these specialconditions on the inventory form sothis information can be used in plan-ning specific improvement projects. Forexample, some spot repairs may berequired.

Occasionally surface conditions varysignificantly within a feature. Forexample, short sections of goodcondition may be followed by sectionsof poor surface conditions. In thesecases, it is best to rate the featureaccording to the worst conditions andnote the variation on the form.

The overall purpose of conditionrating is to be able to compare eachfeature relative to all the other featuresin your airport pavement system. Oncompletion you should be able to lookat any two pavement features and findthat the better surface has a higherrating.

Assessing drainage conditions

Moisture and poor pavement drainageare significant factors in pavementdeterioration. Some assessment ofdrainage conditions during pavementrating is highly recommended. While youshould review drainage in detail at theproject level, at this stage simply includean overview drainage evaluation at thesame time as you evaluate surfacecondition.

Consider both pavement surfacedrainage and lateral drainage (ditches orstorm sewers). Pavement should be ableto quickly shed water off the surface.Ditches should be large and deepenough to drain the pavement andremove the surface water efficiently intoadjacent waterways.

Look at the crown and check for lowsurface areas that permit ponding. Run-ways and taxiways should have approxi-mately a 1.5º% cross slope or crownacross the pavement. Apron areasrequire positive drainage and ofteninclude storm drainage systems.Maintenance of the entire drainagesystem is critical. Ditches, subsurfacedrains and outlets should be inspected

Practical advice on rating airfield pavements

Practical advice on rating airfield pavements20

AC 150/5320-17 Appendix 2 7/12/04

managers use the rating system.However, an individual surface ratingshould not automatically dictate thefinal maintenance or rehabilitationtechnique.

Consider future traffic projections,original construction, and pavementstrength since these may dictate a morecomprehensive rehabilitation than therating suggests.

Summary

Using funds most efficiently requiresgood planning and accurate identifi-

and cleaned regularly.A pavement’s ability to carry heavy

traffic loads depends on both thepavement materials (concrete slab andgranular base) and the strength of theunderlying soils. Most soils lose strengthwhen they are very wet. Therefore, it isimportant to provide drainage to the top layer of the subgrade supportingthe pavement structure.

Planning annual maintenance and repair budgets

We have found that relating a normalmaintenance or rehabilitation procedureto the surface rating scheme helps

cation of appropriate rehabilitationprojects. Assessing pavement conditionsis an essential first step in this process.This pavement surface condition ratingprocedure has proven effective inimproving decision making and usingfunds more efficiently. It can be useddirectly by airport staff and consultantsor combined with additional testing anddata collection in a more comprehensivepavement management system.

References

Asphalt Airfield Pavements PASER Manual, 2003, Engineering ProfessionalDevelopment, College of Engineering, University of Wisconsin-Madison.

Guidelines and Procedures for Maintenance of Airport Pavements, 7/14/03,Federal Aviation Administration, Advisory Circular AC:150/5380-6A.

AC 150/5320-17 Appendix 2 7/12/04

AIRFIELD PAVEMENT INVENTORY

Airfield _______________________________________________________________ Condition survey date _________________________

Done by _____________________________________________________________________________________________________________________________________

Facility (runway, taxiway, apron) __________________________________________________________________________________________________________

Feature description _________________________________________________________________________________________________________________________

Feature location ____________________________________________________________________________________________________________________________

Feature area _________________________________________________________________________________________________________________________________

Construction date __________________________________________________________________________________________________________________________

Pavement type: ■■ Asphalt ■■ Concrete Layer thicknesses: ___________ ___________ ___________

Maintenance history __________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

PASER Rating ( 5 = Excellent, 4 = Good, 3 = Fair, 2 = Poor, 1 = Failed) ■■Comments on pavement and drainage conditions _______________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

Recommended maintenance ___________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

Recommended rehabilitation __________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

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