ASTM_D_7522_-_D_7522M_-_15.pdf

Designation:D7522/D7522M15Standard Test Method forPull-Off Strength for FRP Laminate Systems Bonded toConcrete Substrate1This standard is issued under the fixed designation D7522/D7522M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes the apparatus and procedurefor evaluating the pull-off strength of wet lay-up or pultruded(shop-fabricated)Fiber Reinforced Polymer(FRP)laminatesystems adhesively bonded to a flat concrete substrate.The testdetermines the greatest perpendicular force(in tension)that anFRP system can bear before a plug of material is detached.Failure will occur along the weakest plane within the systemcomprised of the test fixture,FRP laminate,adhesive andsubstrate.1.2 This test method is primarily used for quality controland assessment of field repairs of structures using adhesive-applied composite materials.1.3 This test method is appropriate for use with FRPsystems having any fiber orientation or combination of plyorientations comprising the FRP laminate.1.4 This test method is not appropriate for use as an“acceptance”or“proof”wherein the FRP system remainingintact at a prescribed force is an acceptable result.1.5 Pull-off strength measurements depend upon both ma-terial and instrumental parameters.Different adhesion testdevices and procedures will give different results and cannot bedirectly compared.1.6 This test method can be destructive.Spot repairs may benecessary.The test method will result in an exposed cut FRPsection;repair methods must consider the potential for mois-ture uptake through this cut section.1.7 Prior to the installation of some adhesively bonded FRPsystems,the substrate concrete must be patched(often toreplace lost concrete volume).This test method is not appro-priate for determining the pull-off strength of the FRP from thepatch material.An additional test method is required todetermine the pull-off strength of the patch from the substrateconcrete.Throughout this standard,“substrate”is understoodto mean the concrete or concrete patch material to which theFRP is adhered.1.8 The values stated in either SI units or inch-pound unitsare to be regarded as standard.Within the text,the inch-poundunits are shown in brackets.The values stated in each systemare not exact equivalents;therefore,each system must be usedindependently of the other.Combining values from the twosystems may result in nonconformance with the standard.1.9 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C125 Terminology Relating to Concrete and Concrete Ag-gregatesD883 Terminology Relating to PlasticsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning of Polymer MatrixComposite MaterialsE6 Terminology Relating to Methods of Mechanical TestingE122 Practice for Calculating Sample Size to Estimate,WithSpecified Precision,the Average for a Characteristic of aLot or Process3.Terminology3.1 DefinitionsTerminology D3878 defines terms relatingto high-modulus fibers and their composites.TerminologyD883 defines terms relating to plastics.Terminology E6 definesterms relating to mechanical testing.Terminology C125 definesterms relating to concrete.In the event of a conflict betweenterms,Terminology D3878 shall have precedence over theother standards.1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.10 onComposites for Civil Structures.Current edition approved April 15,2015.Published May 2015.Originallyapproved in 2009.Last previous edition approved in 2009 as D7522/D7522M-09.DOI:10.1520/D7522_D7522M-15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2 Symbols:3.2.1 Ddiameter of the loading fixture.3.2.2 Fppull-off force.3.2.3 ppull-off bond stress.4.Summary of Test Method4.1 The pull-off test is performed by securing a circularloading fixture(dolly)normal(perpendicular)to the flatsurface of the FRP laminate with an affixing adhesive.Anadhesion testing device is attached to the loading fixture andaligned to apply tension normal to the test surface.The forceapplied to the loading fixture is gradually increased andmonito