Concrete Repair According to the new European Standard EN 1504

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Concrete Repair According to the new European Standard EN 1504

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Concrete Repair According to the new European Standard EN 1504Prof. Dr.-Ing. M. Raupach,RWTH Aachen, ibacABSTRACT:GreatefforthasbeenmadetoworkoutaEuropeanStandardonprotectionandrepairofconcretestructures. After more than ten years of intensive discussions within different working groups the series of standards isnow more or less finalised. Actually the European Countries are preparing to replace the existing national standardsandrecommendationsbythenewEuropeanStandardEN1504.Itcanbeassumedthatthisstandardwillhaveasignificant impact also to the Non-European countries.1 INTRODUCTIONRepairandrestorationofconcretestructureshasbecomeanimportantmarket.Asanexamplethecostsfor the maintenance of bridges are higher than 1 billion $per year. The total costs for maintenance of all types ofbuildingscanbeassumedtobehigherthanabout20billion$peryear.Asignificantpartofthiscostsarespentonrepairandprotectionofconcretestructures.On the contrary to the amount of work spent on buildingnewstructures,themarketofrepairandprotectionhasgrownconsiderablyastheageoftheexistinginfrastructureisincreasing.Theextensivedevelopmentofnewmethodsandmaterialsfortherepairandprotectionofconcretestructureshasledtotheneedofstandards for such works and products.Table1showsthestructureofthenewEN1504,consisting of 10 main standards and about 65 standardsfortestmethods.Asshownintable1theseriesofstandards is focused on parts 2 to 7, which are the basisfor CE marking of the different products and systems tobe used for protection and repair of concrete structures.However,part9ofEN1504isnotlessimportant,describingtheprinciplesfortheuseoftheproducts,which will be explained in the following sections. Part 1givesdefinitions,part8regulatesthequalitycontroloftheproductsandpart10givesageneralguidelineforsiteapplicationandqualitycontroloftheworks.ToallowCEmarkingoftheproductsabout65standardsdescribing test methods for the different properties of theproductshadtobeprepared.Thesestandardsensurethat testing of the products will be according to the samestandardsforallproductsforprotectionandrepairofconcrete structures used in Europe.Table 1:Structure of EN 1504EN 1504-9Principles for the use of the productsEN 1504-2 to 7: Test methods(about 65 standards)EN 13 396(chloride ingress)EN 14 497(filtration stability)...Products- surface protection- repair mortars- bonding materials- injection materials- anchoring products - coatings for steelEN 1504-10Site applicationand quality controlof the worksEN 1504-1DefinitionsEN 1504-8 Quality control of the productsFuther test methods2 PHASES OF REPAIR PROJECTSThe phases of repair projects follow a logical sequence,whichisdominatedbyengineeringaspects.Table2givesageneralschemeaccordingtofigureB1withinannexBofEN1504-9.Thisfigureshowsthewell-knownelementsasassessment,planning,designandqualitycontrol.However,thesystematicsofgeneralplanningisquitenewrelatedtotheactuallyexistingrecommendationsandstandards.Itconsistsofahierarchyoflevels,namelyoptions,principlesandmethods,whicharedescribedinmoredetailinsection4.Table 2: The phases of repair projectsManagement of the StructureCondi ti ons andhistory ofstructureClause 8 ofEN 1504-9DocumentationCommissions for maintenanceProcess ofAssessmentDefects and their classifica-tion and causesGeneralPlanningOptionsPrinciplesMethodsClauses 5 and 6 ofEN 1504-9Design ofRepair WorkDefi ni ti ons of theintended use ofproductsEN 1504-2 toEN 1504-7 andclause 7 and annex A ofEN 1504-9Requirements- substrate- products- work- specifications- drawingsRepair WorkChoi ce and useof products andequipmentClause 9 of EN 1504-9 andENV 1504-10Tests of qualitycontrolHealth and safetyAcceptance ofRepair WorkRemedial worksDocumentationAcceptance testingBasic considerations and actionsParts of the EN 1504 series and clauses of EN 1504-94.3 ofEN 1504-93 PROCESS OF ASSESSMENTTable3showscommoncausesofdefectsaccordingtofigure 1 of EN 1504-9. With respect to later planning ofrepair,generallyitshouldbedistinguishedbetweendefects in concrete and defects caused by reinforcementcorrosion. The purpose of the main assessment isto identify the cause or causes of defectsto establish the extent of defectstoestablishwherethedefectscanbeexpectedtospreadtopartsofthestructure,thatareatpresentunaffectedtoassesstheeffectofdefectsonstructuralsafetyandtoidentifyalllocations,whereprotectionorrepairmay be needed.More details on requirements for assessment are given inEN 1504-9.Table 3: Common causes of defectsImpactOverloadMovement(e.g. settlement)ExplosionVibrationMechanicalAlkali-aggregatereactionAggressive agentse.g. sulphates,softwater, saltsBiological activitiesChemicalFreeze/thawThermalSaltcrystallizationShrinkageErosionWearPhysicalDefects in Concrete Reinforcement CorrosionCarbonationStray currentsSodium ChlorideCalciumChloride Other contaminantsSodium ChlorideCorrosive contaminantsAt mixingFrom externalenvironmentFigure 1: Example for a damage of the concreteFigure2:Exampleforreinforcementcorrosioncausedbycarbonation of the concreteFigure3:Exampleforreinforcementcorrosioncausedbychloride ingress4 OPTIONS,PRINCIPLESANDMETHODSFOR PROTECTION AND REPAIRAsalreadymentioned,therulesfortheuseofproductsandsystemsforprotectionandrepairofconcretestructuresisbasedonahierarchyofdifferentlevels,namelyoptions,principlesandmethods.AccordingtoEN1504-9thefollowingoptionsshallbetakenintoaccountindecidingtheappropriateactiontomeetthefuture requirements for the life of the structures:(a)Do nothing for a certain time(b)Re-analysisofstructuralcapacity,possiblyleadingtodowngradingofthefunctionoftheconcretestructure.(c)Preventionorreductionoffurtherdeterioration,without improvement of the concrete structure.(d)Improvement,strengtheningorrefurbishmentofallor parts of the concrete structure.(e)Reconstructionofpartoralloftheconcretestructure and(f)Demolition of all or part of the concrete structure.For protection and repair, different principles have beendefined, separately for repair and protection of damagestotheconcreteanddamagesinducedbyreinforcementcorrosion.Tables4and5showthe6principlesforprotection and repair of concrete and the 5 principles topreventdamagesduetoreinforcementcorrosionrespectively. Theses principles are based on the RILEMTechnicalRecommendation124-SRCStrategiesforrepairofconcretestructuresdamagedbysteelcorrosion.Toprotectorrepairaconcretestructureaccordingtotheprinciplesdifferentmethodsareavailable.Figures8-15inannexAofthispapershowthe methods and short descriptions for the 11 principles.Altogether37methodsaredescribedwithinEN1504-9.NotallofthemarecoveredbytheEN1504series,butbyotherstandards,andsomeofthemareactuallynot standardised, but expected to be regulated in future.Thesystemofoptions,principlesandmethodsisthebasisfortheselectionofproductsbythedesigner.Theprocessofplanningandselectionofproductsisdescribed within the next section.Table 4: Principles for repair and protection for damages of theconcretePrinciple No.Principle 1 [PI]Principle 2 [MC]Principle 3 [CR]Principle 4 [SS]Principle 5 [PR]Principle 6 [RC]Principle and its definitionProtection against ingressMoisture ControlConcrete RestorationStructural StrengtheningPhysical resistanceResistance to chemicalsTable5:PrinciplesforprotectionagainstreinforcementcorrosionPrinciple No.Principle 7 [RP]Principle 8 [IR]Principle 9 [CC]Principle 10 [CP]Principle 11 [CA]Principle and its definitionPreserving or Restoring PassivityIncreasing ResistivityCathodic ControlCathodic ProtectionControl of Anodic areasFigure4:Exampleforsurfacecoatingaccordingtomethod1.2(Table 8), 2.2 (Table 9), 6.1 (Table 12) or 8.1 (Table 14)Figure 5:Exampleforhydrophobicimpregnationaccordingtomethod 2.1 (Table 9)Figure 6:Exampleforapplyingmortarbyhandaccordingtomethod 3.1 (Table 10)Figure 7: Example for recasting with concrete according tomethod 3.2 (Table 10)Figure 8: Example for plate bonding according to method 4.3(Table 11)Figure 9: Example for injection of cracks according to method4.5 (Table 11)5 PLANNING AND SELECTION OFPRODUCTSTable 6 shows thesystematicsofplanningaccordingtoEN1504-9.Asalreadyshownintable2,theplanningstartswiththeassessmentofthestatusofthestructure.Thefollowingpointsareselectionofoptions(repairstrategy), repair principles and repair method, as definedintheprevioussection.Basedonthisselectionschemetherepairmaterialscanbechosen.EN1504-9definesperformancecharacteristicsforeveryrepairmethod,separately for all intendedusesandforcertainintendeduses.Thedesignerselectstheperformancecharacteristicsbasedontherequirementsofthespecialrepair project and the selected repair methods. Table 7gives 3 examples of certain cases, with the performancecharacteristicsrelevantfortheselectedrepairmethods.EN 1504-2 to 7 contain the performance characteristicsoftheproductstogetherwiththecorrespondingtestmethods.Inthiswaytheproductsareselectedindi-vidually for the demands of the special case of repair orprotectionofaconcretestructure.Asaresult,theproducts are described by a list of required performancecharacteristicsinsteadofsimpleclasses,resultinginahighlevelofflexibility,butalsoresponsibilityofthedesigner.Finally inspection and maintenance requirements shall bedefined by the designer.Table 6: Systematics of planning according to EN 1504-9Assessment of the status of the structure (defects ...)Elaboration of the repair strategy (do nothing, repair, ..., demolition)Definition of the repair principles (e.g. protection against ingress ...)Selection of the repair method (e. g. impregnation ...) Definition of the repair materials (strength, modulus, adhesion, etc.)Definition of inspection and maintance requirements6 CONCLUSIONS AND OUTLOOKAnewEuropeanstandardonprotectionandrepairofconcretestructureshasbeenworkedout,basedontheactual state of knowledge regarding the properties of theproducts,theprinciplesfortheuseoftheproducts,application and quality control. Parts 2 to 7 regulate theperformance of the products and systems for protectionandrepairofconcretestructureswithrespecttoCEmarking.Theuseoftheproductsisbasedonalogicalsequence consisting of options (repair strategies), repairprinciples and repair methods, which are listed in tablesin part 9 of EN 1504. This scheme ensures that suitableproductsareselectedbasedontherequirementsofthepractical case. It is expected that this new series of stan-dardswillreplacetheexistingnationalstandardsinEurope within the next 2 or 3 years and that it will alsohave significant impact for other countries.Table 7: Examples of the application of the classification system in 3 individual cases according to EN 1504-2No. accordingto Table 1Test methodsdefined inPerformance characteristicsExample 31.3/5.1Example 21.3/5.1/6.1Example 11.3/2.2EN ISO 5470-1EN12190EN 12617-1EN1062-6EN ISO 7783-2EN1062-31246789121314151820Adhesion after thermal compatibilityFreeze-thaw cycling with de-icing salt immersion EN 13687-1EN 13687-2EN 13529EN 1062-7EN ISO 6272-1EN 1542EN 13036-4EN 1062-11:2002EN 1062-11:2002Linear shrinkageCompressi ve strengthAbrasion resistancePermeability to CO2Permeability to water vapourCapillary absorption and permeability to waterThunder shower cycling (thermal shock)4.1: Aging 7 days at 70 CResistance to severe chemical attackCrack bridging abilityImpact resistanceAdhesion by Pull-off testSlip/Skid resistance4.2 Behaviour after artificial weatheringEXAMPLE 1Coating system for exposed surfaces, not mechanically or chemically loaded, without de-icing salt influence acc. to the principles 1 (IP) and 2 (MC), see Table 1, 1.3 (C) and 2.2 (C).EXAMPLE 2Coating system for interior surfaces, mechanically and chemically loaded, in acc. and 6 (RC), see Table 1, 1.3 (C), 5.1 (C) and 6.1 (C).to the principles 1 (IP), 5 (PR) EXAMPLE 3Crack bridging coating system for exposed surfaces mechanically and lowchemically loaded, with de-icing salt influence in acc. to the principles 1 (IP) and 5 (PR),see Table 1, 1.3 (C) and 5.1 (C).7LITERATURE[1]EN1504-11998-01-00.Productsandsys-temsfortheprotectionandrepairofconcretestructures-Definitions,requirements,qualitycontrolandevaluationofconformity-Part1:Definitions[2]EN1504-22004-10-00.Productsandsys-temsfortheprotectionandrepairofconcretestructures-Definitions,requirements,qualitycontrolandevaluationofconformity-Part2:Surface protection systems for concrete[3]DINEN1504-32001-06-00Productsandsystemsfortheprotectionandrepairofconcrete structures - Definitions, requirements,qualitycontrolandevaluationofconformity-Part3:Structuralandnon-structuralrepair;GermanversionprEN 1504-3:2001(WITHDRAWN in October 2004)[4]EN1504-42004-11-00.Productsandsys-temsfortheprotectionandrepairofconcretestructures-Definitions,requirements,qualitycontroland evaluation of conformity - Part 4:Structural bonding[5]prEN 1504-5 2004-04-00. Products and sys-temsfortheprotectionandrepairofconcretestructures-Definitions,requirements,qualitycontrolandevaluationofconformity-Part5:Concrete injection[6]prEN 1504-6 2004-05-00. Products and sys-temsfortheprotectionandrepairofconcretestructures-Definitions,requirements,qualitycontrolandevaluationofconformity-Part6:Anchoring of reinforcing steel bar[7]DINEN1504-72005-01-00Productsandsystemsfortheprotectionandrepairofconcrete structures - Definitions, requirements,qualitycontrolandevaluationofconformity-Part7:Reinforcementcorrosionprotection;German version prEN 1504-7:2004[8]EN1504-82004-11-00.Productsandsys-temsfortheprotectionandrepairofconcretestructures-Definitions,requirements,qualitycontrolandevaluationofconformity-Part8:Quality control and evaluation of conformity[9]ENV 1504-9 1997-07-00. Products and sys-temsfortheprotectionandrepairofconcretestructures-Definitions,requirements,qualitycontrolandevaluationofconformity-Part9:General principles forthe use of products andsystems[10]EN1504-102003-12-00.Productsandsys-temsfortheprotectionandrepairofconcretestructures-Definitions,Requirements,Qualitycontrol and evaluation of conformity - Part 10:Siteapplicationofproductsandsystemsandquality control of the worksANNEX ATables 8-15:Table 8: Principle no. 1Principle No.Principle 1 [PI]Principle and its definitionProtection against ingressReducing or preventing theingress of adverse agents,e.g. water, other liquids,vapour, gas, chemicals andbiological agents.Methods based on the principle1.11.21.31.41.51.61.7Applying liquid products whichpenetrate the concrete and blockthe pore system.ImpregnationSurface coating with and withoutcrack bridging abilityLocally bandaged cracks 1)Filling cracksTransferring cracks into joints 1)Erecting external panels 1) 2)Applying membranes 1)1) These methods may make use of products and systems not covered by the EN 1504 series2)Inclusion of methods in this Prestandard does not imply their approvalTable 9: Principle no. 21) These methods may make use of products and systems not covered by the EN 1504 series2)Inclusion of methods in this Prestandard does not imply their approvalPrinciple No. Principle and its definition Methods based on the principlePrinciple 2 [MC] Moisture ControlAdjusting and maintainingthe moisture content inthe concret...