nace no. 6/sspc-sp 13, surface preparation of concrete · nace no. 6/sspc-sp 13, surface...

NACE No. 6/SSPC-SP 13Item No. 21082

Revised 2018-05-15Reaffirmed 2003-03-17

Approved 1997

ISBN 1-57590-045-9©2018, NACE International

NACE No. 6/SSPC-SP 13, Surface Preparation of ConcreteThis NACE International/SSPC: The Society for Protective Coatings joint surface prepa-ration standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any respect pre-clude anyone, whether he or she has adopted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard practice. Nothing contained in this NACE/SSPC standard is to be con-strued as granting any right, by implication or otherwise, to manufacture, sell, or use in connection with any method, apparatus, or product covered by letters patent, or as in-demnifying or protecting anyone against liability for infringement of letters patent. This standard represents minimum requirements and should in no way be interpreted as a restriction on the use of better procedures or materials not discussed herein. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circum-stances may negate the usefulness of this standard in specific instances. NACE and SSPC assume no responsibility for the interpretation or use of this standard by other parties, and accept responsibility for only those official NACE or SSPC interpretations issued by NACE or SSPC in accordance with their governing procedures and policies, which preclude the issuance of interpretations by individual volunteers.

Users of this NACE/SSPC standard are responsible for reviewing appropriate health, safety, and regulatory documents and for determining their applicability in relation to this standard prior to its use. This NACE/SSPC standard may not necessarily address all po-tential health and safety problems or environmental hazards associated with the use of materials, equipment, and/or operations detailed or referred to within this standard. Us-ers of this NACE/SSPC standard also are responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regula-tory authorities if necessary, to achieve compliance with any existing applicable regula-tory requirements prior to the use of this standard.

CAUTIONARY NOTICE: NACE/SSPC joint surface preparation standards are subject to periodic review, and may be revised or withdrawn at any time in accordance with NACE/SSPC technical committee procedures. NACE and SSPC require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of initial publication and subsequently from the date of each reaffirmation or revision. The user is cautioned to obtain the latest edition. Purchasers of NACE/SSPC standards may receive current information on all standards and other NACE/SSPC joint publications by contact-ing the organizations at the addresses below:

ABSTRACTThis NACE International/SSPC joint stan-dard practice covers the preparation of con-crete surfaces before the application of pro-tective coating or lining systems. The standard includes two updated tables, Table 1 details classes of surface preparation, and Table 2 provides minimum acceptance crite-ria for concrete surfaces before coatings are applied and relevant test methods. The up-dated Appendix (nonmandatory) includes two additional tables, Table A1 provides typ-ical surface properties of finished concrete, and Table A2 provides an extensive list of surface preparation methods for concrete surfaces. This standard should be used by specifiers, applicators, inspectors, and oth-ers who are responsible for defining a stan-dard degree of cleanliness, strength, profile, and dryness of prepared concrete surfaces.

KEYWORDSabrasive blasting, acid etching, cementitious repair, coating adhesion, coatings, concrete, lining systems, NACE No. 6, protective coat-ing systems, surface preparation, spalling, surface profile, tensile strength, TG 417, vacuum cleaning, waterjetting

©2018 NACE International, 15835 Park Ten Place, Suite 200, Houston TX 77084, USA. All rights reserved. Reproduction, republication or redistribution of this standard in any form without the express written permission of the publisher is pro-hibited. Contact NACE International by means of our website www.nace.org, email [email protected], or (phone) 281-228-6223 for reprints of this standard.

NACE International15835 Park Ten Place

Houston, TX 77084-5145+1 281-228-6200

SSPC: The Society for Protective Coatings800 Trumbull Drive

Pittsburgh PA 15205+1 412-281-2331

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2 — NACE No. 6/SSPC-SP 13 NACE International©2018 NACE International, 15835 Park Ten Place, Suite 200, Houston TX 77084, USA. All rights re-served. Reproduction, republication or redistribution of this standard in any form without the express written permission of the publisher is prohibited. Contact NACE International by means of our website www.nace.org, email [email protected], or (phone) 281-228-6223 for reprints of this standard.

ForewordThis NACE International/SSPC Joint standard covers the preparation of concrete surfac-es before the application of protective coating or lining systems. This standard should be used by specifiers, applicators, inspectors, and others who are responsible for defining a standard degree of cleanliness, strength, profile, and dryness of prepared concrete surfaces.

This standard was originally prepared in 1997 by NACE/SSPC Joint Task Group (TG) F, “Surface Preparation of Concrete.” It was reaffirmed in 2003 by NACE Specific Technol-ogy Group (STG) 04, “Coatings and Linings, Protective—Surface Preparation,” and SSPC Group Committee C.2, “Surface Preparation.” It was revised in 2018 by TG 417 (formerly Task Group F). This standard is issued by NACE under the auspices of STG 04, and by SSPC Group Committee C.7.7.

In NACE/SSPC standards, the terms “shall,” “must,” “should,” and “may” are used in accordance with Paragraph 2.2.1.8 of the Agreement between NACE International and SSPC: The Society for Protective Coatings. The terms “shall” and “must” are used to state mandatory requirements. The term “should” is used to state something considered good and is recommended but is not mandatory. The term “may” is used to state something considered optional.


NACE International NACE No. 6/SSPC-SP 13 — 3©2018 NACE International, 15835 Park Ten Place, Suite 200, Houston TX 77084, USA. All rights re-served. Reproduction, republication or redistribution of this standard in any form without the express written permission of the publisher is prohibited. Contact NACE International by means of our website www.nace.org, email [email protected], or (phone) 281-228-6223 for reprints of this standard.

NACE No. 6/SSPC-SP 13, Surface Preparation of Concrete

1. General ....................................................................................................................4

2. Definitions ................................................................................................................5

3. InspectionProceduresBeforeSurfacePreparation .................................................6

4. SurfacePreparation .................................................................................................8

5. InspectionandClassificationofPreparedConcreteSurfaces ...............................10

6. AcceptanceCriteria ................................................................................................12

7. SafetyandEnvironmentalRequirements...............................................................13

References .............................................................................................................13

AppendixA:Comments(Nonmandatory)...............................................................17

Tables

Table1:ClassesofSurfacePreparation ..................................................................4

Table2:MinimumAcceptanceCriteriaforConcreteSurfacesBefore CoatingsareApplied ................................................................................12

TableA1:TypicalSurfacePropertiesofFinishedConcrete ...................................17

TableA2:SurfacePreparationMethods................................................................21



Section 1: General1.1 ThisNACE/SSPCstandarddetails the requirements forsurfacepreparationof

concretebymechanicalandchemicalmethodsbeforetheapplicationofbondedprotectivecoatingorliningsystems.

1.2 The standard details specific methods of surface preparation as well as theamountofsurfacecleanlinessandprofileachievablebyeachmethod.Thespec-ifierisresponsibleforchoosingtheappropriateclassofsurfacepreparationfromTable1fortheintendedprotectivecoatingandintendedserviceconditionsandtheseshouldbeagreeduponbyallpartiesinvolved(ownerand/orspecifier,man-ufacturerandcontractor).

Table 1 Classes of Surface Preparation

Class Method Profile Range (CSP)(A)

Section Referenced

D-VC VacuumCleaning NC(B) 4.2.2W-LP LowPressureWaterRinse NC(B) 4.2.2W-DS DetergentScrubbing NC(B) 4.2.3W-SC SteamCleaning NC(B) 4.2.3W-AE AcidEtching 1 – 3 4.4

W-WJ Waterjetting(includesHydrodemolitionandHydroblasting) 3 – 10 4.3.2

M-GRD Grinding–Dry 1 – 2 4.3.4M-GRW Grinding–Wet 1 – 2 4.3.4M-ABD AbrasiveBlasting–Dry 3 – 7(A) 4.3.1M-ABW AbrasiveBlasting–Wet 3 – 7(A) 4.3.1M-SB ShotBlasting 3 – 9(A) 4.3.1M-SC Scarifying 4 – 7 4.3.3(A)ICRI(1)310.2,1ConcreteSurfaceProfiles(CSP); see footnote in Appendix A,Table A2. (B)NoChange

1.3 Therequirementsofthisstandardareapplicabletoalltypesofcementitioussur-facesincluding,butnotlimitedto,cast-in-placeconcretefloorsandwalls,precastslabs,masonrywalls,shotcretesurfacesandcementitiousgrouts,overlaymentsand/orunderlayments.

1.4 Thecompositionandinstallationofnewconcreteandcementitiousrepairmate-rialmayaffecttheselectionandapplicationofacoatingsystem.Itistherespon-sibilityofthedesignertospecifytheconcretecomposition,admixtures,finishingprocedures,curingmethodorcompoundandformreleaseagents;andcementi-tiousrepairmaterialsthatensuretheconcreteissuitableforcoating.Thechemi-cal, physical (abrasion), and environmental exposure conditions alsomust bedefinedfortheappropriatecoatingsystemtobeselected.

1.5 Existingconcretesurfacesmustbeproperlyevaluatedbeforetheapplicationofacoatingsystem.Itistheresponsibilityoftheowner/specifiertoassessthecondi-tionoftheconcretetoensurethesubstrateissoundandsuitableforcoating.

1.6 Anacceptable prepared concrete surface should be free of contaminants, lai-tance,looselyadheringconcrete,anddust,andshouldprovideasound,uniformsubstratesuitablefortheapplicationofprotectivecoatingorliningsystems.

(1)International Concrete Repair Institute (ICRI), 3166 S. River Road, Suite 132, Des Plaines, IL 60018.



1.7 Thisstandardprovidesminimumrequirements foraconcretesurfacefollowingsurfacepreparationandspecifictestmethodsandacceptancecriteriaforsurfacetensile strength, profile, cleanliness, residual contaminants, pH, and moisturecontent.

1.8 ThemandatoryrequirementsofthisstandardaregiveninSections1to7asfollows:

Section1: GeneralSection2: DefinitionsSection3: InspectionProceduresBeforeSurfacePreparationSection4: SurfacePreparationSection5: InspectionandClassificationofPreparedConcreteSurfacesSection6: AcceptanceCriteriaSection7: SafetyandEnvironmentalRequirements

1.9 AppendixA(Nonmandatory)doesnotcontainmandatoryrequirements.

Section 2: DefinitionsCoating: See Protective Coating or Lining System.

Concrete: Amaterialmadefromhydrauliccementandinertaggregates,suchassandandgravelthatismixedwithwatertoaworkableconsistencyandplacedbyvariousmeth-odstohardenandgainstrength.

Curing (Concrete): Actiontakentomaintainmoistureandtemperatureconditions inafreshlyplacedcementitiousmixturetoallowhydrauliccementhydrationsothatpotentialpropertiesofthemixturemaydevelop.

Curing Compound (Membrane Curing Compound):Aliquidthatcanbeappliedtoformamembraneonthesurfaceofnewlyplacedconcretetoretardthelossofwater.2

Efflorescence:Agenerallywhitedepositformedwhenwater-solublecompoundsemergeinsolutionfromconcrete,masonry,orplastersubstratesandprecipitatebyreactionsuchascarbonationorcrystallizebyevaporation.2

Fins:Anarrowlinearprojectiononaformedconcretesurface,resultingfrommortarflow-ingintospacesintheformwork.2

Finish:Thetextureofaconcretesurfaceafterconsolidatingandfinishingoperationshavebeenperformed.2

Finishing:Leveling,smoothing,consolidating,andotherwisetreatingsurfacesoffreshorrecentlyplacedconcreteormortartoproducedesiredappearanceandservice.2

High-Pressure Water Cleaning (HP WC):Watercleaningperformedatpressuresfrom34to70MPa(5,000to10,000psig).3

High-Pressure Waterjetting (HP WJ): Waterjettingperformedatpressuresfrom70to210MPa(10,000to30,000psig).3

Honeycomb:Voidsleftinconcreteduetofailureofthemortartoeffectivelyfillthespacesamongcoarseaggregateparticlesorotherobstructions.2

Laitance:Athin,weak,brittlelayerofcementandaggregatefinesonaconcretesurface.Theamountoflaitanceisinfluencedbythetypesandamountsofadmixtures,thedegreeofworking,andtheamountofwaterintheconcrete.4



Lining: See Protective Coating or Lining System.

Porosity:Smallvoidsthatallowfluidstopenetrateanotherwiseimperviousmaterial.

Protective Coating or Lining System (Coating):Forthepurposesofthisstandard,pro-tectivecoatingorliningsystems(alsocalledprotectivebarriersystems)arebondedther-moset,thermoplastic,inorganic,organic/inorganichybrids,ormetallicmaterialsappliedinoneormorelayersbyvariousmethodssuchasbrush,roller,trowel,spray,andthermalspray.Theyareusedtoprotectconcretefromdegradationbychemicals,abrasion,physi-caldamage,andthesubsequentlossofstructural integrity.Otherpotentialfunctionsin-cludecontainingchemicals,preventingstainingofconcrete,andpreventingliquidsfrombeingcontaminatedbyconcrete.

Release Agents (Form-Release Agents):Materialsusedtopreventbondingofconcretetoasurface.2

Scaling:Localflaking,orpeelingaway,ofthenear-surfaceportionofhardenedconcreteormortar.

Sealer (Sealing Compound):Aliquidthatisappliedtoaconcretesurfacetopreventordecreasethepenetrationofliquidorgaseousmediaduringexposure.Somecuringcom-poundsalsofunctionassealers.

Soundness:Aqualitativemeasureofthesuitabilityoftheconcretetoperformasasolidsubstrateorbaseforacoatingorpatchingmaterial.Soundconcretesubstratesusuallyexhibitstrengthandcohesivenesswithoutexcessivevoidsorcracks.

Spalling (Concrete):Thespontaneouschipping,fragmentation,orseparationofasurfaceorsurfacecoating.(Forthepurposesofthisdocument,spallingincludesafragment,usu-ally in the shape of a flake, detached from a largermass by a blow, by the action ofweather, bypressure, or byexpansionwithin the largermass;a small spall involvesaroughlycirculardepressionnotgreaterthan120mm(5in)indepthand150mm(6in)inanydimension;alargespall,mayberoughlycircularorovalorinsomecaseselongated,ismorethan120mm(5in)indepthand150mm(6in)ingreatestdimension.)

Surface Porosity:Porosityorpermeabilityattheconcretesurfacethatmayabsorbva-pors,moisture,chemicals,andcoatingliquids.

Surface Preparation:Themethodorcombinationofmethodsusedtocleanaconcretesurface,removelooseandweakmaterialsandcontaminantsfromthesurface,repairthesurface,and roughen thesurface topromoteadhesionofaprotectivecoatingor liningsystem.

Surface Profile (Texture):Surfacecontourasviewedfromtheedge.

Surface Air Voids:Cavitiesvisibleonthesurfaceofasolid.

Ultra-High-Pressure Waterjetting (UHP WJ): Waterjetting performed at pressuresgreaterthan210MPa(30,000psig).3

Section 3: Inspection Procedures Before Surface Preparation

3.1 Concreteshallbeinspectedbeforesurfacepreparationtodeterminethecondi-tionoftheconcreteandtodeterminetheappropriatemethodorcombinationofmethodstobeusedforsurfacepreparationtomeettherequirementsofthecoat-



ingsystemtobeapplied.Inherentvariationsinsurfaceconditionsseeninwallsandceilingsversusthoseinfloorsshouldbeconsideredduringtheselectionofsurfacepreparationmethodsandtechniques.Forexample,wallsandceilingsaremuch more likely than floors to contain surface air voids, fins, form-releaseagents,andhoneycombs.ACI(2)364.1R4providesusefulguidanceforinspectionandevaluationofstructures.

3.2 Visual Inspection

Allconcretesurfacestobepreparedandcoatedshallbevisuallyinspectedforsignsofconcretedefects,physicaldamage,chemicaldamage,contamination,andexcessmoisture.

3.3 The Degree of Concrete Cure

AllconcreteshouldbecuredusingtheproceduresdescribedinACI308.5Curingrequirementsincludemaintainingsufficientmoistureandtemperaturesforamin-imumtimeperiod.Surfacepreparationperformedoninsufficientlycuredorlow-strengthconcretemaycreateanexcessivelycoarsesurfaceprofileorremoveanexcessiveamountofconcrete.

3.4 Concrete Defects

Concretedefectssuchashoneycombsandspallingshallberepaired.Theproce-duresdescribedinICRI310.1,6orACI3017maybeusedtoensuretheconcretesurfaceissoundbeforesurfacepreparation.FurtherinformationoninvestigationofdefectsmaybefoundinICRI210.48andNACESP0308.9

3.5 Physical Damage

3.5.1 Severalcommonsurfacepreparationmethodsarelikelytoreducethetensilestrengthofthepreparedsubstrate.Bondstrengthsachievedonsurfacespreparedwithhigh-impactmechanicalcleaningmethodsarefrequentlyshowntobelowerthanthoseachievedwhennonimpactcleaningmethodsareused.Thisreductioninbondstrengthcanbeattributedto“bruising,”crackingofthecementpaste,andlooseningoftheaggregatewithoutfullyseparatingfromtheunderlyingconcrete.Thislayerofinterconnectingmicrocrackstypicallyextendstoadepthof3to10mm(0.12to0.4in)anditisgenerallyacceptedthatdamageincreaseswiththeincreasingweightandpoweroftheequipmentused.

3.5.2 Concrete should be tested for soundness by the qualitativemethodsdescribedinAppendixA,ParagraphA4.3.

3.5.3 Whenqualitativeresultsareindeterminate,orwhenaquantitativeresultisspecified,concreteshallbetestedforsurfacetensilestrengthusingthemeth-odsdescribedinAppendixA,ParagraphA8.

3.5.4 Concretethathasbeendamagedbecauseofphysical forcessuchasimpact,abrasion,orcorrosionofreinforcementshallberepairedbeforesurfacepreparationifthedamagewouldaffectcoatingperformance.RepairsshouldbemadeinaccordancewithACI301,ACI562,10ACI546,11NACESP0390,12orAp-pendixA,ParagraphA4.

3.6 Chemical Damage

(2)American Concrete Institute International (ACI), 38800 International Way, Country Club Drive, Farmington Hills, MI 48331.



3.6.1 Concrete is attacked by a variety of chemicals, as detailed in ACI515.2R13andPCA(3)IS001.14

3.6.2 All concrete surfaces that have been exposed to chemicals shall betestedandtreatedforcontaminationasdescribedinParagraph3.7.

3.6.3 Concretethathasbeenexposedtochemicalsshallbetestedforsound-nessbythequalitativemethodsdescribedinAppendixA,ParagraphA4.3.

3.7 Contamination

3.7.1 Contaminationonconcretesurfacesincludesallmaterialsthatmayaf-fect theadhesionandperformanceof thecoating tobeapplied.Examples in-clude,butarenotlimitedto,dirt,oil,grease,chemicals,andexistingincompatiblecoatings.

3.7.2 ContaminationmaybedetectedbymethodsdescribedinAppendixA,ParagraphA5.Thesemethodsinclude,butarenotlimitedto,visualexamination,waterdrop(contactangle)measurement,pHtesting,petrographicexamination,andvariousinstrumentalanalyticalmethods.Coresamplingmayberequiredtodeterminethedepthtowhichthecontaminanthaspenetratedtheconcrete.

3.7.3 ConcretesurfacesthatarecontaminatedorthathaveexistingcoatingsshallbetestedbythemethoddescribedinAppendixA,ParagraphA8todeter-minewhetherthecontaminationorexistingcoatingaffectstheadhesionandper-formanceofthecoatingtobeapplied.

3.7.4 Inextremecasesofconcretedamageordegradation,orthoroughpen-etration by contaminants, complete removal and replacement of the concretemayberequired.

3.8 Moisture

MoisturelevelsintheconcretemaybedeterminedbythemethodsdescribedinParagraph5.5.

Section 4: Surface Preparation4.1 Objectives

4.1.1 Theobjectiveofsurfacepreparation is toproduceaconcretesurfacethat issuitable forapplicationandadhesionof thespecifiedprotectivecoatingsystem.

4.1.2 Protrusionssuchasfromsharpedges,fins,andconcretespattershallberemovedduringsurfacepreparation.

4.1.3 Voidsandotherdefectsthatareatornearthesurfaceshallbefullyex-posedduringsurfacepreparation.

4.1.4 Allconcretethatisnotsoundshallberemovedsothatonlysoundcon-creteremains.

4.1.5 Concretedamagedbyexposuretochemicalsshallberemovedsothatonlysoundconcreteremains.

(3) Portland Cement Association (PCA), 5420 Old Orchard Rd., Skokie, IL 60077.



4.1.6 All contamination, form-release agents, efflorescence, curing com-pounds,andexistingcoatingsdeterminedtobeincompatiblewiththecoatingtobeappliedshallberemoved.

4.1.7 Thesurfacepreparationmethod,orcombinationofmethods,shouldbechosenbasedontheconditionoftheconcreteandtherequirementsofthecoat-ingsystemtobeapplied.

4.1.8 Allpreparedconcretesurfacesshallberepairedtothelevelrequiredbythecoatingsystemintheintendedservicecondition.

4.2 Surface Cleaning Methods

4.2.1 ThesurfacecleaningmethodsdescribedinParagraphs4.2.2and4.2.3shallnotbeusedasthesolesurfacepreparationmethodofconcretetobecoatedastheydonotremovealllaitanceorcontaminantsoralterthesurfaceprofileofconcrete.Thesemethodsshallbeusedasrequired,beforeand/oraftertheme-chanicalandchemicalmethodsdescribedinParagraphs4.3and4.4andtheef-fectivenessofanysurfacepreparationshouldbeverifiedfollowinganymethodselected.

4.2.2 Vacuumcleaning,airblastcleaning,andwatercleaningasdescribedinASTM(4) D425815maybeusedtoremovedirt, loosematerial,and/ordust fromconcrete.

4.2.3 Detergent water cleaning and steam cleaning as described inASTMD4258maybeusedtoremoveoilsandgreasefromconcrete.

4.3 Mechanical Surface Preparation Methods

4.3.1 Dryabrasiveblasting,wetabrasiveblasting,vacuum-assistedabrasiveblasting,andcentrifugalshotblasting,asdescribed inASTMD4259,16maybeusedtoremovecontaminants, laitance,andweakconcrete, toexposesubsur-facevoids,andtoproduceasoundconcretesurfacewithadequateprofileandsurfaceporosity.SeeTableA2.

4.3.2 High-orUltra-Highpressurewatercleaningorwaterjettingmethodsasdescribed in the four joint NACE/SSPCwaterjetting standards,ASTMD4259,ICRI310.3R,17or theWaterJetTechnologyAssociation’s(5) (WJTA-IMCA)“Rec-ommendedPractices for theUse ofHighPressureWaterjettingEquipment,”18

maybeusedtoremovecontaminants,laitance,existingcoatings,andweakcon-crete,toexposesubsurfacevoids,andtoproduceasoundconcretesurfacewithadequateprofileandsurfaceporosity.SeeAppendixA,TableA2.

4.3.3 Impact-toolmethodsmaybeusedtoremoveexistingcoatings,laitance,and weak concrete. These methods include scarifying, scabbling, and rotarypeening,asdescribedinASTMD4259.Impact-toolmethodsmayfracturecon-cretesurfacesorcausemicrocrackingandmayneedtobefollowedbyoneoftheprocedures inParagraphs4.3.1or4.3.2 toproduceasoundconcretesurfacewithadequateprofileandsurfaceporosity.ThesoundnessofaconcretesurfacepreparedusinganimpactmethodmaybeverifiedbyoneofthesurfacetensilestrengthtestsdescribedinAppendixA,ParagraphA8.

4.3.4 Power tool methods, including circular grinding, sanding, and wirebrushingasdescribedinASTMD4259,maybeusedtoremoveexistingcoatings,laitance,weakconcrete,andprotrusions inconcrete.Thesemethodsmaynot

(4)ASTM International, 100 Barr Harbor Dr., West Conshohocken, PA 19428-2959. (5)WaterJet Technology Association, 917 Locust, Suite 1100, St. Louis, MO 63101-1419.



producetherequiredsurfaceprofileandmayrequireoneoftheproceduresde-scribedinParagraphs4.3.1or4.3.2toproduceaconcretesurfacewithadequateprofileandsurfaceporosity.SeeTableA2.

4.3.5 SurfacepreparationusingthemethodsdescribedinParagraphs4.3.1through4.3.4shallbeperformedinamannerthatprovidesauniform,soundsur-facethatissuitableforthespecifiedprotectivecoatingsystem.

4.4 Chemical Surface Preparation

Acidetching,asdescribedinASTMD4260maybeusedtoremovelaitanceandweak concrete and to provide a surface profile on concrete surfaces.19 ThismethodrequirescompleteremovalofallreactionproductsandpHtestingtoen-sureneutralizationoftheacid.Acidetchingshouldnotbeusedinareaswherecuringcompounds,sealersorcontaminantspreventtheacidfromreactingwiththe concrete.Acid etching shall only be usedwhere procedures for handling,containment,anddisposalofthehazardousmaterialsareinplace.Acidetchingwithhydrochloricacid(e.g.,muriaticacid)shallnotbeusedwherecorrosionofmetalintheconcrete(rebarormetalfibers)islikelytooccur.

4.5 Surface Cleanliness

After the concrete surface has been prepared to the required soundness andsurfaceprofile,surfacesmaystillneedtobecleanedbyoneofthemethodsde-scribedinParagraph4.2toremovetheresiduecreatedbythesurfaceprepara-tionmethodortoremovespentmedia.

4.6 Patching and Repairs

4.6.1 Beforeproceedingwithpatchingandrepairs,thepreparedconcretesur-faceshallbeinspectedinaccordancewithSection5.Afterthepatchingandre-pairs of the concrete surfaceare completed, the repairedareas shall be rein-spectedinaccordancewithSection5.

4.6.2 Allgouges,surfaceairvoids,andothersurfaceanomaliesshallberepairedtoalevelrequiredbythecoatingsystemasspecifiedintheprocurementdocuments.

4.6.3 All repair materials, both cementitious and polymeric, should be ap-provedorrecommendedbythecoatingmanufacturerasbeingcompatiblewiththecoatingtobeapplied.

4.6.4 Therepairmaterialshallbecuredinaccordancewiththemanufacturer’spublishedinstructions.

4.6.5 Therepairedsectionmayrequireadditionalsurfacepreparationbeforecoatingapplication.

Section 5: Inspection and Classification of Prepared Concrete Surfaces

5.1 ConcreteSurfaceTensileStrengthandCoatingAdhesion

5.1.1 ASTM D723420 is used to measure coating adhesion; the preferredmethodistoapplyatestpatchoftheintendedcoatingsystem(orjusttheprimer)overthepreparedconcretesurfaceandthenperformASTMD7234onthecoated(orprimed)concretesurface.(SeeAppendixA,ParagraphA8.)



5.1.2 Ifitisnotpossibletoapplyatestpatchoftheintendedprimerorcoatingsystem,orwherethereisaneedtoverifyordeterminethetensilestrengthofthebareconcretesurfaceorconcreterepairmaterial,ASTMC158321shouldbeper-formedafterthespecifiedsurfacepreparationhasbeencompleted.(SeeAppen-dixA,ParagraphA8.)

5.2 Surface Profile

5.2.1 Ifaspecificsurfaceprofileisrequiredfortheperformanceofthecoatingsystemtobeapplied,theprofileshallbespecifiedintheprocurementdocuments.

5.2.2 Thesurfaceprofileofpreparedconcretesurfacesshouldbeevaluatedaftercleaninganddryingbutbeforerepairsorapplicationofthecoating.

5.2.3 Thesurfaceprofilemaybeevaluatedbycomparing theprofileof thepreparedconcretesurfacewith the ICRIGuidelineNo.310.21concretesurfaceprofile(CSP)comparatorchips.

5.2.4 Ifacceptedbyallparties, themethodsdescribed inAppendixA,Para-graphA7alsocanbeusedtodeterminethesurfaceprofileoftheconcretesurface.

5.3 Surface Cleanliness

5.3.1 All prepared concrete surfaces shall be inspected for surface cleanli-nessaftercleaninganddryingbutbeforemakingrepairsorapplyingthecoating.RefertoAppendixA,ParagraphA5.Iftheconcretesurfacesarerepaired,theyshallbereinspectedforsurfacecleanlinessbeforeapplyingthecoating.

5.3.2 Preparedconcretesurfacesmaybeinspectedforsurfacecleanlinessbylightlyrubbingthesurfacewithadarkclothorpressingatranslucentadhesivetapeonthesurface.Thetestmethodandacceptablelevelofresidualdustshallbeagreedonbyallparties.

5.3.3 Themethodusedtoverifycompatibilityofthecoatingtobeappliedoveracontaminatedsurfaceorovercontaminatedsurfacesthathavebeencleanedandpreparedshouldbeapprovedbythecoatingmanufacturerandspecifiedintheprocurementdocuments.

5.4 pH

5.4.1 IfaspecificpHrangeisrequiredforproperperformanceofthecoatingsystemtobeapplied,thepHoftheconcreteandacceptablemethodsofmea-surementshallbespecifiedintheprocurementdocuments.

5.4.2 ASTMD426222orotheragreeduponmethodscanbeusedtodeterminepH.

5.4.3 Iftheconcretesurfacesarepreparedbyacidetching,pHmeasurementsofconcretesurfacesshouldbeconductedafterrinsing,butbeforethepreparedsurfacehasdried.

5.5 Moisture Content

5.5.1 If specificmoisture content is required for proper performance of thecoatingsystemtobeapplied,themoisturecontentoftheconcreteandaccept-ablemethodsofmeasurementshallbespecifiedintheprocurementdocuments.

5.5.2 Preparedconcretesurfacesshouldbetestedforresidualmoistureaftercleaninganddryingbutbeforetheapplicationofthecoating.



5.5.3 ASTMD4263,23ASTMF1869,24 orASTMF217025 should be used todeterminetheresidualmoisturecontentinconcrete.ACI302.226shouldbeusedasaguideforfurtherinformation.

5.5.4 Ifrequiredoracceptedbyallparties,anyofthemethodsdescribedinPara-graph5.5.3maybeusedtodeterminethemoisturecontentoftheconcretesurface.

Section 6: Acceptance Criteria6.1 Theminimumacceptancecriteriaforpreparedconcretesurfacesshallbeinac-

cordancewithTable2,orasspecifiedintheprocurementdocuments.

6.2 IftherequirementsbythemanufacturerforspecificcoatingsaremorestringentthanlistedinTable2,themorestringentrequirementsshallapply.

Table 2 Minimum Acceptance Criteria for Concrete Surfaces Before Coatings are AppliedProperty Test Method Light Service(A) Severe Service(B)

Surfacetensilestrength ASTMD7234 1.4MPa(200psi)

min.2.1MPa(300psi)min.

and/orSurfacetensilestrength ASTMC1583 1.4MPa(200psi)

min.1.7MPa(250psi)min.

Surfaceprofile ICRINo.310.2 CSP2min. CSP3min.

Surfacecleanliness ASTMD4258(Visibledust) Nosignificantdust Nosignificantdust

Residualcontami-nants(C) ASTMF2127,28

Waterdropletswetsurfaceimmediatelyformingacontinu-ousuniformfilm

Waterdropletswetsurfaceimmediatelyformingacontinu-ousuniformfilm

pH(acidetching) ASTMD4262–1pHto+2pHchangeinrinsewater

NotRecommended

Moisturecontent(D) ASTMD4263 Novisiblemoisture Novisiblemoistureand/or

Moisturecontent(D) ASTMF186915g/24hr/m2(3lb/24hr/1,000ft2)max.

15g/24hr/m2(3lb/24hr/1,000ft2)max.

and/orMoisturecontent(D) ASTMF2170 80%max. 80%max.(A)Lightservicereferstoexposureconditionssuchaslighttraffic(i.e.,foottrafficandlightrubberwheeledcarts),moisture,nonaggressivechemicalsorfreeze/thawcycles. (B)Severeservicereferstoexposureconditionssuchasheavymachinerytraffic(i.e.,forklifts,heavytrucks,orsteelwheeledcarts),deleteriouschemicals,immersionorthermalshock(e.g.,hotwaterwashingorsteamcleaning). (C)ThoughthefiguresinASTMF21depicttheassessmentresultsonnickelspecimens,thestandardandwaterfilmsdepictedareapplicabletoconcretesurfaces. (D)NOTE: TherearetwoscenarioswherethecriteriaforMoistureContentinTable2maynotapply.Thefirstisatorbelowgradeoroutdoorslabsorwallswhereitmaybeimpossibleorimpracticaltoachievethelowlevelofmoistureindicated.Thesecondscenarioiswheremoisturesuppressingormoisturetolerantcoatingsarespecified.SeeParagraphA9inAppendixAformoreinformation.



Section 7: Safety and Environmental Requirements

7.1 Disposalofcontaminants,oldcoatings,acidfrometching,andcontaminatedwaterandblastingmedia shall complywithall regulationsof theapplicable facility andregulatoryagencies.

7.2 Handlingofhazardousmaterials,machineryoperations,workerprotection,andcon-trolofairbornedustandfumesshallcomplywithallhealthandsafetyregulationsoftheapplicablefacilityandregulatoryagencies.

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26. ACI302.2R(latestrevision),“GuideforConcreteSlabsthatReceiveMoisture-SensitiveFlooringMaterials”(FarmingtonHills,MI:ACI).

27. ASTMF21(latestrevision),“StandardTestMethodforHydrophobicSurfaceFilmsbytheAtomizerTest”(WestConshohocken,PA:ASTM).

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29. T.I.Aldinger,B.S.Fultz,“KeystoSuccessfullyPreparingConcreteforCoating,”JPCL6,5(1989):pp.34-40.

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31. R.Boyd,“QualityControlinCleaningandCoatingConcrete,”SSPC91-19:ProtectiveCoatingsforFlooringandOtherConcreteSurfaces,November10-15,1991(Pittsburgh,PA:SSPC,1991),pp.5-7.

32. L.D.Vincent,Corrosion Prevention by Protective Coatings,2nded.(Houston,TX:NACE,1999).

33. NACESP0892(latestrevision),“CoatingsandLiningsoverConcreteforChemicalImmersionandContainmentService”(Houston,TX:NACE).



34. NACE6G197/SSPC-TU2(latestrevision),“Design,Installation,andMaintenanceofCoatingSystemsforConcreteUsedinSecondaryContainment,”(Houston,TX:NACE,andPittsburgh,PA:SSPC).

35. ASTMPCN:03-401079-14,“ManualofCoatingWorkforLight-WaterNuclearPowerPlantPrimaryContainmentandOtherSafety-RelatedFacilities”(WestConshohocken,PA:ASTM,1979),pp.114-119.

36. H.H.Baker,R.G.Posgay,“TheRelationshipBetweenConcreteCureandSurfacePreparation,”JPCL8,8(1991):pp.50-56.

37. T.I.Aldinger,“CoatingNewConcrete:WhyWait28Days?”SSPC91-19:ProtectiveCoatingsforFlooringandOtherConcreteSurfaces,November10-15,1991(Pitts-burgh,PA:SSPC,1991),pp.1-4.

38. J.Steele,“EffectiveSealing,PrimingandCoatingofNewandUncuredConcrete,”Concrete:SurfacePreparation,CoatingandLining,andInspection,January28-30,1991(Houston,TX:NACE,1991).

39. F.Hazen,“RepairingConcretePriortoLiningSecondaryContainmentStructures,”JPCL8,1(1991):pp.73-79.

40. C.T.Grimm,“CleaningMasonry:AReviewoftheLiterature,”Publication#TR2-88,ConstructionResearchCenter,(Arlington,TX:UniversityofTexasatArlington,Novem-ber1988).

41. S.Lefkowitz,“ControlledDecontaminationofConcrete,”Concrete:SurfacePreparation,CoatingandLining,andInspection(Houston,TX:NACE,1991).

42. R.A.Nixon,“AssessingtheDeteriorationofConcreteinPulpandPaperMills,”Con-crete:SurfacePreparation,CoatingandLining,andInspection,January28-30,1991(Houston,TX:NACE,1991).

43. ASTMC805,“StandardTestMethodforReboundNumberofHardenedConcrete”(WestConshohocken,PA:ASTM,1979).

44. ASTMC597,“StandardTestMethodforPulseVelocityThroughConcrete”(WestConshohocken,PA:ASTM,1979).

45. N.C.Duvic,“SurfacePreparationofConcreteforApplicationofProtectiveSurfacingorCoating,”Concrete: Surface Preparation, Coating and Lining, and Inspection(Houston,TX:NACE,1991).

46. P.J.Fritz,“TheUseofCaptiveShot(Roto-Peening)forPreparingtheSurfaceofConcrete,”SSPC93-06:InnovationsforPreservingandProtectingIndustrialStruc-tures,November13-18,1993(Pittsburgh,PA:SSPC,1993),pp.144-147.

47. K.Pashina,“Planning,ProperSurfacePreparationEssentialforSuccessfulCoatings,”Concrete Repair Bulletin7,1(1994):pp.4-8.

48. ASTMD7682,“StandardTestMethodforReplicationandMeasurementofConcreteSurfaceProfilesUsingReplicaPutty”(WestConshohocken,PA:ASTM,1979).

49. J.Steele,“TestingAdhesionofCoatingsAppliedtoConcrete,”MP33,11(1994):pp.33-36.

50. Kanare,H.“ConcreteFloorsandMoisture,”PCAEB119(Skokie,IL:PortlandCementAssociation,2005).



51. ACI302.1(latestversion),“GuideforConcreteFloorandSlabConstruction”(FarmingtonHills,MI:ACI).

52. ASTME1745(latestversion),“StandardSpecificationforPlasticWaterVaporRetardersUsedinContactwithSoilorGranularFillunderConcreteSlabs”(WestConshohocken,PA:ASTM).

53. ASTMF2659(latestversion),“StandardGuideforPreliminaryEvaluationofCom-parativeMoistureConditionofConcrete,GypsumCementandOtherFloorSlabsandScreedsUsingaNon-DestructiveElectronicMoistureMeter”(WestConsho-hocken,PA:ASTM).

54. W.J.Warlow,“OsmosisasaCauseofBlisteringofinsituresinflooringonwetconcrete,”MAGCONCRRES;30,104(1978)pp.152-156.

55. M.GunterandH.Hildorf,“StressesduetoPhysicalandChemicalActionsinPolymerCoatingsonaConcreteSubstrate,”inAdhesionBetweenPolymersandConcrete,ed.H.R.Sasse(London,UK:ChapmanandHall,1986),pp.8-21.

56. F.A.Pfaff,andF.S.Gelfant,“OsmoticBlisteringofEpoxyCoatingsonConcrete,”JPCL,Dec1997.

57. S.Ignoul,F.VanRickstal,D.VanGemert,“Blisteringofepoxyindustrialflooron concretesubstrate:phenomenaandcasestudy,”Proceedings 11thICPIC ConferenceonPolymersinConcrete(Berlin,Germany:ICPIC,2004).

58. C.Scialo,“BlisteringinResinousSystemsonConcreteSurfaces:Types,CausesandPreventiveMeasures,”JPCL,Jan2007.

59. P.Muhlenbrock,“OsmosisResistantEpoxyPrimer,”InternationalesKolloquium,Jan16-18,2007,Stuttgart,Germany.

60. R.Davis,N.Baetsle,“PhenalkaminesinConcreteApplications”(GlenEllyn,IL:ThermosetResinFormulatorsAssociation(6)[TRFA],2003).

61. M.Cook,etal,“NovelTechnologyfor2KWaterVaporPermeableEpoxyFloorSystems:AEuropeanPerspective,”JPCL,Feb2002,pp.51-56.

62. R.Nixon,“AvoidingOsmoticBlisteringinResinousFloorCoatings,”JPCL,Nov2004,pp.3642.

63. L.Wolff,etal,“BlisteringofResinCoatingsonConcrete:CausesandPrevention,”JPCL,Dec2007,pp.30-46.

64. M.Raupach,L.Wolff,“Durabilityandadhesionofepoxycoatingsonconcrete:CausesofDelaminationandBlistering,”Concrete Repair, Rehabilitation, andRetrofitting II–Alexanderetal(eds),2009.

65. S.Aher,etal,“BlisteringofIndustrialFlooronConcreteSubstrate:TheRoleoftheAirOverpressure,”COMSOLConference,India,2010.

66. M.King,H.Kanare,“EvaluatingMethodsforWaterVaporTransmissionofMoistureVaporSuppressionCoatingsonConcrete,”JAI,3,9,Oct.2006,ASTM.

67. ASTMF3010(latestversion),“StandardPracticeforTwo-ComponentResinBasedMembrane-FormingMoistureMitigationSystemsforUseUnderResilientFloorCoverings”(WestConshohocken,PA:ASTM).

(6) Thermoset Resin Formulators Association (TRFA), 800 Roosevelt Road, Building C, Suite 312, Glen Ellyn, IL 60137.



Appendix A Comments (Nonmandatory)

This appendix is considered nonmandatory, although it may contain mandatory language. It is intended only to provide supplemen-tary information or guidance. The user of this standard is not required to follow, but may choose to follow, any or all of the provisions herein.

A1 General29-32

A1.1 Thisstandarddoesnotrecommendsurfacepreparationmethodsordifferentiatelevelsofsurfacepreparationthatarespecificallyrequiredforvariousprotectivesystemdesigns,types,thicknesses,andend-userequirements.Thesespecificationsshouldbedecidedandagreeduponbyallparties(e.g.,thespecifier,facilityowner,coatingmanufacturer,andcontractor).

A1.2 Concreteanditssurfacesarenothomogeneousorconsistentand,unlikesteel,cannotbediscretelydefined.There-fore,visualexaminationofaconcretesurfaceissomewhatsubjective.Theacceptanceorrejectionofapreparedconcretesur-faceshouldbebasedontheresultsofspecifictests,including,butnotlimitedto,testsforsurfacetensilestrength,contamination,andmoisture.Testapplicationsoftheproposedprimersorcoatingsystemsalsoshouldbeconductedandtested.

A1.3 Joints,cracks,andcuringshrinkageofconcrete,chemicalexposureandmechanicalabrasionshouldbeconsideredinthedesignoftheprotectivecoatingsystem;however,thesetopicsarebeyondthescopeofthisstandard.SeeNACESP0892,33 ACI515.2R,13andNACEPublication6G197/SSPC-TU234formoreinformation.

A1.4 Whenasignificantamountofweak,deteriorated,orcontaminatedconcreteisremovedduringthecourseofsurfacepreparationtoachieveasoundsurface,theprofileofremainingconcreteisoftentooroughfortheintendedcoatingsystem.Inthesecases,andwhereformvoidsandsurfaceairvoidsmustbefilled,patchingorgroutingmaterialsarespecifiedtorepairorleveltheconcretesurface.SeeNACESP0892,NACESP0390,NACEPublication6G197/SSPC-TU2,andParagraphA4.4ofthisAppendixformoreinformationaboutpatchingmaterials.

A2 Concrete Finishing and Surface Characteristics

A2.1 Themethodusedtofinishconcretesurfacesaffectstheconcrete’ssurfaceprofile,composition,porosity,anddensity.Thesesurfacepropertiesaffecttheadhesionandperformanceofconcretecoatings.TypicalsurfacepropertiesobtainedusingthemostcommonfinishingmethodsaregiveninTableA1.Thesepropertiesareevaluatedbeforesurfacepreparation.

Table A1 Typical Surface Properties of Finished ConcreteMethod Profile(A) Porosity(A) Strength(A) Problems

Formedconcrete Smoothtomedium Lowtomedium Medium Voids,protrusions,releaseagents

Woodfloat Medium Medium MediumMetaltrowel Smooth Low HighPowertrowel Smooth Verylow High VerydenseBroomfinish Coarsetoverycoarse Medium Medium

Sacking Smooth Lowtomedium Lowtohigh(B) Weaklayerifnotproperlycured

Stoning Smoothtomedium Lowtomedium Lowtohigh(B) Weaklayerifnotproperlycured

Concreteblock Coarsetoverycoarse Veryhigh Medium

Relativelyhighdegreeofporosity/potentialforpinholesinappliedcoatings

Shotcrete(C) Verycoarse Medium Medium Tooroughforthincoatings

(A)Thesesurfacepropertiesarebasedonsimilarconcretemix,placement,andvibrationandbeforesurfacepreparation.(B)Strengthdependsonapplicationandcure.(C)Shotcretemayberefinishedafterplacement,whichwouldchangethesurfacepropertiesgiveninthistable.



A2.2 Nopreferredmethodoffinishingconcretetoacceptcoatingshasbeenestablishedbytheconcretecoatingindustry.Thesurfacecure,surfacepreparationmethod,andtypeofcoatingsystemtobeappliedareallfactorsindeterminingthesuit-abilityofanyspecificconcretefinishingmethod.Forexample,broomfinishingissometimesusedbecauseitgivesaprofileforthecoating;however,mostoftheprofilemayberemovedduringsurfacepreparationifthesurfaceisnotproperlycured,negat-ingthisinherentadvantageofthebroomfinish.Whensackingisusedtofillvoidsinformedconcretesurfaces,subsurfacevoidsarecreated,andtheaddedcementisusuallyremovedduringsurfacepreparationasaresultof impropercureoftheaddedcementpaste.

A2.3 Useofametaltrowelisgainingacceptanceasthepreferredfinishingmethodforhorizontalsurfacestobecoatedpro-videdthesurfaceisnotexcessivelytrowelled,theconcreteiscuredproperly,andthelaitanceisremovedbeforecoating.

A2.4 PhotographicexamplesofconcretefinishesareshowninASTMPCN:03-401079-14.35

A3 ConcreteCure36

A3.1 Maintainingsufficientmoistureandpropertemperatureinconcreteintheearlystagesofcureisimportanttoensuredevelopmentofthedesignedstrength.Keepingthesurfacemoistuntilsufficientstrengthhasdevelopedatthesurfaceisimport-anttoensureformationofsufficientsurfacestrength,toreducecurling,andtoreducesurfacecracking.

A3.2 ACI3085recommendssevendaysofmoistcuringforTypeIportlandcementconcreteandthreedaysforTypeIIIportlandcementconcrete,ifthetemperatureisabove10°C(50°F).ACI308alsorecommendsnumerousmethodstoproperlycureconcrete,includingtheuseofsealingmaterialsandothermethodstokeepconcretemoist.

A3.3 ACI308alsogivesrecommendationsontheuseofcuringcompounds,whicharecommonlyusedimmediatelyafterplacementandfinishingofconcretesurfacestoreducemoisturelossandimprovesurfacecure.Thecuringcompoundshouldeitherbecompatiblewiththecoatingorberemovedduringsurfacepreparation.

A3.4 TheTraditional28-dayWaitingPeriod37,38

A3.4.1 Thetraditional28-daywaitingperiodafterconcreteplacementandbeforecoatinginstallationisacontrover-sialtopicthatinvolvesallparties.Althoughthewaitingperiodisnotusuallyrequiredforsurfacepreparation,itaffectsthetimingofsurfacepreparationbecausemanycoatingsareappliedwithin24hoursaftersurfacepreparation.

A3.4.2 The28-daywaitingperiodoriginatedfromthestructuralbenchmarktotestconcretestrengthat28daysafterplacementtoverifythatthetestedstrengthmetthedesignstrength.The28-daywaitingperiodwasadoptedbythecoatingindustrybecauseitusuallyallowssufficienttimeforconcretesurfacestrengthtodevelopandforexcessmois-turetoevaporate.

A3.4.3 Manyfactorscanreduceorincreasethetimerequiredforstrengthandmoisturelevelstobeacceptable.Inaddition,manyconstructionschedulesdonotallowfora28-daywaitingperiod.Forthesereasons,quantifyingsurfacerequirementsarepreferredoverthetraditional28-daywaitingperiod.SeeParagraphA8.

A3.4.4 NACESP0892doesnot recommendaspecificcureperiod,butdoesaddresssurfacedryness, surfacestrengthrequirementsandothersurfacequalityissues.

A4 Identification and Repair of Surface Defects and Damage39

A4.1 PhysicalandChemicalDamage

A4.1.1 Existingconcretestructuresthathavebeensubjectedtomechanicaldamage(causedbyimpactorabra-sion),chemicalattack,orrebarcorrosionarerestoredtoprovideauniform,soundsubstratebeforecoatingapplication.

A4.1.2 Tobestreceiveandholdthepatchingmaterialalldeterioratedconcreteshouldberemovedandthesur-roundingsoundconcretecutusingtheproceduresdescribedinICRI310.16Somecontaminantshaveadetrimentaleffectontherebarortheappliedcoatingiftheyarenotcompletelyremoved.



A4.1.3 Anumberofpolymericgroutsandpatchingmaterialscanbeused,especiallywhenthecoatingistobeap-pliedimmediately.Thesematerialsshouldbecompatiblewiththecoatingtobeapplied.

A4.2 Other Defects and Imperfections

A4.2.1 Defectssuchashoneycombs,scaling,andspallingdonotprovideasound,uniformsubstrateforthecoat-ing.Thesedefectsare repairedby removingall unsoundconcreteand thenpatching the concretebefore surfacepreparation.NACESP0390andICRI310.1describeremovalandrepairproceduresforconcretethatisspalledbe-causeofrebarcorrosion.

A4.2.2 Surfaceairvoids,pinholes,orexcessiveporositymayaffecttheapplicationorperformanceofthecoating.Themaximumsubstratevoidsizeorsurfaceporositythatcanbetolerateddependsonthecoatingsystemundercon-sideration.Ifvoidsarenotfilledbeforethecoatingisapplied,thetrappedairvaporexpandsandcontractsandmayaffecttheperformanceofthecoating.Forliquid-richcoatings,excessporosityatthesurfacemayresultinpinholesinthecoating.Voidsareusuallyfilledaftersurfacepreparationandbeforecoatingapplication.

A4.2.3 Protrusionssuchasformlines,fins,sharpedges,andspattermaycauseholidaysorthinsectionsinthecoatingiftheyarenotremoved.Protrusionsandroughedgesareusuallyremovedduringsurfacepreparation.

A4.3 Testing for Surface Soundness

A4.3.1 Thefollowingarecommonmethodsusedtodeterminesurfacesoundness:

(a) Ascrewdriver,file,orpocketknifeislightlyscratchedacrosstheconcretesurface.Ifthemetalobjectridesoverthesurfacewithoutlooseninganyparticlesandleavesnomorethanashinymark,thesurfaceissound.Ifthisprocessgougesthesurface,thesurfaceisnotsound.

(b) Theconcretesurfaceislightlystruckwiththeedgeofahammerhead.Ifthehammerreboundssharplywithnomorethanasmallfractureattheimpactarea,thesurfaceissound.Ifitlandswithadullthudandleavespowdereddustsintheindentation,thesurfaceisnotsound.

(c) Achainisdraggedacrosshorizontalconcretesurfaces.Differencesinsoundindicateunsoundconcreteandholesorpocketswithintheconcrete.

A4.4 Patching of Concrete Surface Imperfections

A4.4.1 RepairMaterialsareusedtorepair,patch,smooth,orsealtheconcretesurfacetoprovideasubstratethatissuitableforthecoatingsystemtobeapplied.Thesematerialsareappliedaftersurfacepreparationandrequirethefollowingcharacteristics:

(a) goodadhesiontotheexistingsubstrate;(b) adequatestrengthtomeettheserviceconditionsofthecoatingsystem;(c) lowvolumetricandlinearshrinkageduringcureundertheenvironmentalserviceconditions;and(d) compatibilitywiththecoatingtobeapplied.

Inaddition,thepatchingmaterialisoftenrequiredtocuresufficiently,betrafficbearing,andbereadytorecoatinashort timeframe(usuallywithin24hours).

A4.4.2 Shrinkageofthepatchingmaterialmayreducetheadhesionofthatmaterialtotheconcretesubstrate.Dif-ferencesinthermalexpansionbetweentheconcrete,patchingmaterial,andcoatingsystem,causestressesduringthermallyinducedmovementthatmayreduceadhesionbetweentheselayers.

A4.4.3 Themostcommon typesofpatchingmaterialsarecementitious,polymer-modifiedcementitious (usuallyacrylic),andpolymeric(usuallyepoxyorurethane).Cementitiousmaterialsarelowerincostthanpolymericmaterials,butpolymericmaterialsgenerallycurefasterandhavehigherstrengths,betteradhesion,andincreasedchemicalre-sistance.

A4.4.4 Patchingmaterialsareavailableinarangeofconsistenciesforapplicationtoverticalorhorizontalsurfacesbyavarietyofmethods.Theamountoffilleralsovaries.Forexample,groutsfordeeppatchingaretypicallyhighly



filled,whileporositysealersmaybeminimallyfilledorunfilled.Numerousproprietarymaterialsarelow-shrinking,non-shrinking,orexpanding.

A4.4.5 Additionalsurfacepreparationmayneedtobeperformedoncuredpatchingmaterialstoensurethepatchedsurfacemeetstherequirementsofthecoatingsystem.

A5 Identification and Removal of Contaminants40-42

A5.1 Hydrophobic Materials

A5.1.1 Hydrophobiccontaminantsmayexistonneworexistingconcretesurfacesasform-releaseagents,curingcompounds,sealers,existingcoatings,oil,wax,grease,resinsorsilicone.Theymaybequalitativelydetectedbyasimplewaterdroptestwheretheycausethewatertobeaduponthesurface.Aspecificprocedureforconductingthistypeoftestin-situandquantifyingtheresultsisfoundinASTMF21.27Ifthewater-droporatomizertestisinconclusive,afewdropsofmuriaticacidmaybedroppedonthesurface;ifthereisnovisiblefoamingreaction,thenacontaminantexistsonthesurface.Analyticaltechniquessuchasinfraredanalysisorgaschromatographymayalsobeusedtode-tectandidentifythesecontaminantsincoresamples.

A5.1.2 Oilsandgreasescanberemovedbysteamcleaning,bakingsodablastingorwashingwithalkalinedeter-gentsanddegreasers.Whendepositsareveryheavy,scrapingortheuseofabsorbentsmaybenecessaryinconjunc-tionwiththesemethods.Thesurfacemustbethoroughlyrinsedofallcleaningsolutionsandtestedagainbeforefurthersurfacepreparationisconducted.Hydrocarbonsolventsarenotrecommendedforoilandgreaseremovalastheytendtospreadthecontaminationandfacilitatefurtherpenetrationintotheconcrete.

A5.1.3 Curingcompounds,sealers,form-releaseagents,andcoatingsshouldberemovedbytheleastdestructive,mostpractical,economic,andsafemethodavailable.Removalmethodssuchasgrinding,abrasiveblasting,wetabra-siveblasting,waterjettingorscarifyingareoftenused.Chemicalstrippersaregenerallynotrecommended.Insomecases,themanufacturerofthecoatingsystemtobeappliedmayconsidertheexistingsealerorcuringcompoundtobecompatiblenegatingtheneedforremoval.

A5.2 Laitance

A5.2.1 Laitanceisaweaklayeroffineparticlesofcementandaggregateformedonthesurfacewhentheconcreteisoverworkedoroverwet(seedefinitioninSection2).Laitancemustberemovedbeforetheapplicationofacoatingsystem.Mostcoatingsformatenaciousbondtothelaitance,butthelaitanceisafriablelayerthatisonlylooselyad-heredtotheconcreteunderneath.Ifnotremovedduringsurfacepreparation,thecoatingandlaitancedetachattheinterfacebetweenthelaitanceandconcretesubstrate.Laitancemaybedetectedbyrunningasharpinstrument,suchasascrewdriver,overthesurfacewithmoderate-to-heavypressureandnotingthemarkleftonthesurface.Laitancetypicallyfracturesorcrumbles,leavingpowderyorgrittyresiduebehind.LaitancemayberemovedusingthemethodsdescribedinTableA2.

A5.3 Salts and Reactive Materials

A5.3.1 Salts,sulfates,efflorescence,chemicalreactionproductssuchas,acids,alkalis,andbyproductsofchemi-calattackofconcrete,cansometimesbedetectedbypHtesting,soundnesstestingusingthescrewdrivertest,orvisualexamination.Whenthesemethodsarenotsuccessful,chemicalanalysistechniquesarerequired.

A5.3.2 Efflorescenceconsistsofsaltsthatarecarriedtothesurfacebythemigrationofwaterthroughtheconcrete.Thewaterevaporatesleavingthesaltdepositbehind.Forthisreason,itisimportanttoascertainthesourceofthemois-turewhentheconcreteistobecoatedtoavoidothercomplicationssuchasdetachmentbyhydrostaticpressure.Someofthesesaltsmayremainwatersolublesothathigh-pressurewaterwashingalonemaycausethemtopenetratebackintotheconcrete.Othersmayreactwiththeatmosphereandbecomewaterinsoluble.Thesaltsmayberemovedbybrushingwithastiffbrushfollowedbywaterwashingorbyabrasiveblasting.Insomecases,theymayberemovedbyfirstuniformlywettingthesurfacewithwater,thenapplyingadilutedsolutionofmuriaticoraceticacidfollowedimmedi-atelybyanalkaliwashandrinsing.Inaddition,thesaltsmayberemovedbyusingthemethodsdescribedinTableA2.

A5.3.3 Residualacidsandalkalisarefirstneutralizedandthenremovedbyhigh-pressurewatercleaning.



A5.4 Microbial Induced Concrete Corrosion

A5.4.1 Microorganisms such as fungus, moss, mildew, algae, decomposing organic matter, and other organicgrowthscansometimesbedetectedbyvisualexaminationandinsomecasesbytestingthepH.Theeffectsofmicro-bialinfestationmaybepurelyaesthetic,suchasinthecaseofmildewstaining,butmicrobiallyinducedconcretecorro-sionasseeninareassuchassewersanddigesterseventuallyaffectsthestructuralintegrityoftheconcrete.Inthecaseofthelatter,ahammertestmaybeusedtocheckforintegrityoftheconcretesurface(ASTMC80543),orevenanultrasoundtestfordeepercorrosion(ASTMC59744).

A5.4.2 Microorganismscreatinganaestheticissuesuchasfungus,moss,algaeand/ordecomposingorganicmat-terareremovedbyscraping,abrasiveblasting,orwaterjettingfollowedbytreatingthesurfacewithsodiumhypochlorite(householdbleach)andrinsingwithwater.

A5.4.3 Concretethatissusceptibleto,orhassustaineddamagesuchasfromacidproducingbacteria,shouldfirstbepreparedbyoneofthemethodslistedinTableA2toprovideasoundconcretesurface.Asurfaceappliedcorrosioninhibitormaybeappliedbeforetheintendedcoatingsystem.

A6 Surface Preparation Methods45-47

ThesurfacepreparationmethodsdescribedinthisstandardarelistedinTableA2withtheirintendeduse,profilecreated,typicalproblemsencounteredwhenusingeachmethod,andsolutionstothoseproblems.AdditionalinformationmaybefoundinICRI310.2.

Table A2 Surface Preparation MethodsClass Preparation Method When Used Profile Created(A) Problems SolutionsD-VC VacuumCleaning Removesloosedebris

onlyNoChange N/A N/A

W-LP LowPressureWaterCleaning(B)

CleansSurfacing NoChange WetsConcrete Letconcretedry

W-DS DetergentScrubbing Emulsifiesoilandgrease NoChange Detergentandemulsifiedcontaminants

LowpressurewaterrinseLetconcretedry

W-SC SteamCleaning CleansSurface,removessomeoilandgrease

NoChange WetsConcrete Letconcretedry

W-AE AcidEtching Removeslaitance,impartsaprofileandcleanssurface

CSP1toCSP3 Hazardous,neutralization,inhibitedbymembranes,curingcompounds,greaseandoilcontamination,wetsconcrete

UseotheracidspHtestingLetconcretedryUseothermethods

W-WJ HighandUltraHighPressureWaterjetting

Removeslaitanceandsomeconcrete,impartsaprofileandcleanssurface

CSP3toCSP10 WetsconcreteCoarseprofile

LetconcretedryNone(C)

M-GRD DryGrinding Removeslaitance,impartsaprofileandcleanssurface

CSP1toCSP2 Dustanddebris Vacuumclean

M-GRW WetGrinding Removeslaitance,impartsaprofileandcleanssurface

CSP1toCSP2 Wetsludge,debrisWetsconcrete

LowpressurewaterrinseLetconcretedry

M-ABD Dryabrasiveblasting Removeslaitanceandsomeconcrete,impartsaprofileandcleanssurface

CSP2toCSP7 DustanddebrisAirbornedustNoise

VacuumcleaningVacuumNone

M-ABW Wetabrasiveblasting Removeslaitanceandsomeconcrete,impartsaprofileandcleanssurface

CSP2toCSP7 WetsconcreteCreatessludge

LetconcretedryCleaning



M-SB ShotBlasting Removeslaitanceandsomeconcrete,impartsaprofileandcleanssurface

CSP3toCSP7(A) StrayShot Cleansurfacemagnetically

M-SC Scarifying Removeslaitanceandsomeconcrete,impartsaprofileandcleanssurface

CSP4toCSP7 DustanddebrisBruising,striatedpatternonsurface

VacuumcleaningNone(C)

NeedleScaling(D) Removeslaitanceandsomeconcrete,impartsaprofileandcleanssurface

CSP2toCSP4 Dustanddebris,striatedpatternonsurface


Scabbling(D) Removeslaitanceandsomeconcrete,impartsaprofileandcleanssurface

CSP7toCSP10(A) DustanddebrisBruising,irregularsurfacepattern


Rotomilling(D) Removeslaitanceandsomeconcrete,impartsaprofileandcleanssurface

CSP9toCSP10(A) DebrisBruising,groovingofsurfaceandtoolmarks

Sweeping,VacuumcleaningNone(C)

(A)TheCSPprofileproducedbythevariouspreparationmethodslistedherearedefined inICRI310.2.NOTE: TheremaybesomedifferencesbetweenthisstandardandICRIontheactualprofilerangeachievedbyeachsurfacepreparationstandard.EachmethodproducesarangeofCSPprofilesdependingonthequalityandstrengthoftheconcreteandthedegreetowhichthemethodisapplied.AnonaggressiveuseofapreparationmethodongoodqualityconcreteresultsinaCSPprofileatthelowendoftherangeoflistedprofiles(alesscoarsesurface).Whenselectingapreparationmethod,atestareashouldbeperformedtodeterminetheCSPprofile.

(B)Lessthan34MPa(5,000psi)waterpressure.(C)Forcoatingsystemsthatdonotperformoveracoarseprofile,refinishingtheconcreteoranunderlaymentmayberequired.(D)Methodisrarelyusedandincludedhereinforinformationalpurposesonly.

A7 Surface Profile

A7.1 Inadditiontoremovinglaitance,weakconcrete,andcontaminationattheconcretesurface,surfacepreparationusuallyopenstheporesand/orcreatesaprofileontheconcretesurface.Profileincreasesthesurfaceareaavailableforbondingbe-tweentheconcreteandthecoating,enhancesadhesionattheconcrete/coatinginterface,andhelpsthecoatingresistpeelingandshearforces.

A7.2 Thedepthofsurfaceprofilerequireddependsonthecoatingsystemtobeusedandthemanufacturer’srecommenda-tion.Factorsthatmayinfluencetheprofileselectedinclude:

(a) tensileandshearstrengthoftheconcreteandthecoatingsystem;(b) adhesionofthecoatingsystemtotheconcrete;(c) internalstressesinthecoatingsystemcreatedduringapplicationandcure(e.g.,fromshrinkage);(d) differenceinthecoefficientofthermalexpansionbetweenthecoatingandtheconcrete;(e) modulusorstress-relaxationpropertiesofthecoatingsystem;(f) thermalandchemicalexposureenvironment;and(g) coatingthickness.

A7.3 ASTMD768248describesamethodofusingareplicaputtytoquantifythesurfaceprofileofconcrete.TheprofilealsocanbesubjectivelycomparedwithICRI310.2R(moldedconcretesurfaceprofilereplicas).

A8 Concrete Surface Tensile Strength and Coating Adhesion Testing49

A.8.1 Itisimportanttobeabletocharacterizethestrengthoftheconcretesurface,preparedinaccordancewithoneormoreoftheproceduresinthisstandard,toensureitisstrongenoughforadequateadhesionofthecoatingtobeapplied.ASTMC1583issuitablefordeterminingpull-offtensilestrengthnearthesurfaceoftheconcrete(Meaningthatthetensilestrengthofthecon-creteatthedepthofthescoringismeasured,assumingthatfailureoccursatthatlocation).Iffailureoccursatthedollyadhesiveandconcretesurfaceinterface,itisdefinedasbondfailure.Forbothmethods(ASTMD7234andASTMC1583),iffailureoccursbetweenthedollyandthedollyadhesivetheresultisnotrecordedasvalidandmustbediscardedorrepeated.

A.8.2 Thoughdesignedspecificallytomeasureadhesionofcoatingstoconcretesurfaces,ASTMD7234isthemostusedandacceptedmethodforensuringadequatetensilestrengthofconcretesurfacesforthespecifiedcoating.ASTMD7234includesalldetailsrelevanttotestingpull-offstrengthofcoatingsonconcreteincludingequipmentdetailsandlimitations,loadingrates,and



interpretationoffailuremodes.

A.8.3 ASTMD7234specificallydetailsscoringthroughthecoatingdowntothesurfaceoftheconcrete,andthereforediffersfromASTMC1583,whichspecificallydetailsscoringintotheconcrete,wellbelowthesurface.Thereasonforthisdifferencecanbeattributedtothepurposeandscopeofeachofthesemethods,thefirstintendingtoisolatethetestconditionsandaddressthecoating/substrateadhesionandthesecondintendingtoensurethatthetensilestrengthoftheconcreteisthelimitingfactorintheresult.

A.8.4 Therearemanyreasonstotestforsurfacestrength(eitherwithorwithoutthecoatingapplied).Theseincludeensuringthesurfacepreparationtechnique(s)usedwassuccessful,andthepreparedconcretesurfaceisfreefromcontaminants,laitanceisremoved,thesurfaceisnot“bruised”ormicro-fractured,andalthoughnotdeterminedorcontrolledbythesurfacepreparation,thattheconcreteprofileorsurfaceporosityissufficientforthecoating.

A.8.5 Becauseofthevariabilityinconcrete,thesurfacepreparationmethodsusedandthechoiceandoperationoftheinstru-ments,thereisalargemarginoferrorinthepull-offstrengthresultsobtainedfromthesemethods.Therefore,itisincumbentonallpersonsperformingthetestingand/orspecifyingthenumericresultsthatequalattentionispaidtothemodeoffailureanditisobserved,interpreted,andtheconsequencesunderstood.

A9 Moisture

This topic(moisture inconcretefloorsandrelatedcoating issues) iscovered inextensivedetailbyKanare in2005.50Somehighlightsonthistopicandupdatesareinthissection.

A9.1 SourcesofMoistureinConcrete

A9.1.1 Moistureorexcessmoistureinconcretecancomefrommultiplesources.Inthe2004update,ACI302.151 recommendedusingavaporbarrierinaccordancewithASTME174552forconcreteslabsplacedon-gradetobefin-ishedwithmoisturesensitiveproducts.Fornewconcrete,excesswatercancomefromwaterofconvenienceduringplacementorrainaftertheinitialcuringprocessforconcreteexposedtotheenvironment.Forexistingconcretestruc-tures,wherethewaterfrominitialplacementandconstructionisnolongerafactor,andapositivesidevaporbarrieriseitherabsentornotperformingadequately(e.g.,perforated)thewatertableandcapillaryrisecanfeedtheconcreteandthesurfacewithacontinuedsourceofmoisture.

A9.1.2 Moisturetestingofconcretefloorsisperformedbyvariousmethods,allofwhichmeasuredifferentphenom-ena.Historically,moisturewastestedbyindicationofmoistureinconcretebyplasticsheetmethod(ASTMD426323),orthemeasurementofmoisturevaporemissionsrateofconcretesubfloorusinganhydrouscalciumchloridemethod(ASTMF1869),bothofwhichindicatemoistureemissionsduringthespecifictimethatthetestisconducted,qualifyingorquantifyingmoistureatornearthesurfaceatthetimeoftestingrespectively.Othermethodsusingportablehandheldinstruments,includingelectricalresistanceorelectricalimpedance(ASTMF265953),arecommonlyusedtoperformapreliminaryevaluationandcomparethemoistureconditioncontent;however,theresultsofthistestarenotintendedtoprovidequantitativedataasabasisforacceptanceofafloorforinstallationofamoisturesensitiveflooringsystem.More recently in theUnitedStates (longer in theEuropeanUnion) relativehumidity testing in theconcrete (ASTMF2170)hasbeenusedtoassesstheinsituconcretemoisturelevels.Mostmanufacturersofmoisturesensitivecoatingsystemssetmaximummoistureemissionratesrangingfrom3to5lb./1000ft2/24hrwhentestedinaccordancewithASTMF1869,and/orinsiturelativehumiditycontentfrom75%to80%whentestedinaccordancewithASTMF2170;however,thematerialmanufacturer’sguidanceshouldbefollowedregardingthemoisturetoleranceoftheirmaterial.Notethatmoisturelevelsatthetimeoftestingandinstallationarenotanindicatorofmoisturelevelsinthefuture,whicharedictatedbythepresenceorlackofanintactmoisturebarrierundertheconcrete,subterraneangroundwaterlevels,changeinenvironmentalconditions,andconcreteproperties,allofwhicharebeyondthecontroloftheanysurfacepreparationmethodortheintendedcoatingsystem.

A9.2 Issues from Excess Moisture

Issuesfromexcessmoistureforfloorcoatingsystems(whichisthemostresearched)rangefromblistering(mostcommon),toliquidexudingthroughpinholesinthecoating,tocompletedisbondment.Whiletherearemanytheoriesandsomeresearchintothereasonsforcoatingblisteringordisbonding,thereislittleresearchintothefactorsorpredictorsofthesevariouscoatingis-suesfromtheconcreteorconcretesurface(otherthanalkali-silicareaction[ASR]whichisaspecialcase).Whilesomeofthecoatingfailurescanbeattributedtolackofsurfacepreparationorsufficientsurfaceprofile;andpotentialformulationorinstalla-



tionissuesincludingmulticomponentmaterialsbeingmixedoff-ratio,insufficientmixing,unacceptableenvironmentalconditions(temperature,humidity,anddewpoint)duringapplicationandcure;trappedair,ormissingrequiredintercoatapplicationwin-dows,therearestillmanyinstanceswheredisbondmentorblisteringoccurswhenallthesefactorsareprecluded.

A9.3 Theories of Moisture Issues:

Publishedtheoriesofthevariousmechanismsforblisteringinflooringcanbedividedintotwogroups:

A9.3.1 Osmosis—Osmoticblisteringusuallydoesnotappearuntilmonthsaftercoatingapplication,andoftenpresentsaspressurizedliquidfilledblisters.Thistheoryassumesconcreteisthesemipermeablemembrane,solublesaltsareextractedfromtheconcreteand/orthecoating,andthebonded,impermeablecoatingactsasthecontainment.54-58Inaddition,whilead-mittingtotheosmoticphenomena,somecompaniestoutformulasthatareresistanttotheprocess.59-61

ConditionsNecessaryforOsmoticBlistering62 (a) WaterSource(b) Abilityofwatertomoveintheconcrete(c) Pressuretightcoating(d) Semi-permeablemembrane(e) Solublesalts/dissolvedionsbetweensemi-permeablemembraneandcoating(f) Defectsitesorvoidsattheconcrete/coatinginterface

A9.3.2 Nonosmosis—Thereareresearcherswhoclaimthatblisteringisnotanosmoticprocess,andhavevarioustheoriesandcausesrangingfromvaporpressure,capillarypressure,diffusiontransport,cureinhibition,excessalkali,andASR,tonameafew.63-65

A9.4 Moisture Mitigation Practices

Whilebeyondthescopeofthisstandard,inadditiontothedetailsforsurfacepreparationgiveninthisstandardandcarefulcontrolofthecoatingapplication,guidelinesfornegativesidecontrolorreliefofmoistureissuesinconcretefallintotwocategories,treat-mentsappliedtotheconcretesurfaceandalternatecoatingformulations.Inthefirstcategory,thesetreatmentsincludepolymermodifiedcementitiousunderlayments,fibrousorpermeableunderlayments,andmoisturesuppressioncoatings.66-67 Inthesecondcategory,alternativecoatingsystemsincludespecificformulationrestrictions,orpermeablecoatingorflooringsystems.



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NACE NACE No. 6/SSPC-SP 13 ISBN 1-57590-045-9Item #21082 NACE International

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