ASTM_D_6087_-_22.pdf

Designation:D608722Standard Test Method forEvaluating Asphalt-Covered Concrete Bridge Decks UsingGround Penetrating Radar1This standard is issued under the fixed designation D6087;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers several ground penetratingradar(GPR)evaluation procedures that can be used to evaluatethe condition of concrete bridge decks overlaid with asphalticconcrete wearing surfaces.These procedures can also be usedfor bridge decks overlaid with portland cement concrete andfor bridge decks without an overlay.Specifically,this testmethod predicts the presence or absence of concrete or rebardeterioration at or above the level of the top layer of reinforc-ing bar.1.2 Deterioration in concrete bridge decks is manifested bythe corrosion of embedded reinforcement or the decompositionof concrete,or both.The most serious form of deterioration isthat which is caused by corrosion of embedded reinforcement.Corrosion may be initiated by deicing salts,used for snow andice control in the winter months,penetrating the concrete.Inarid climates,the corrosion can be initiated by chloride ionscontained in the mix ingredients.Deterioration may also beinitiated by the intrusion of water and aggravated by subse-quent freeze/thaw cycles,causing damage to the concrete andsubsequent debonding of the reinforcing steel with the sur-rounding compromised concrete.1.2.1 As the reinforcing steel corrodes,it expands andcreates a crack or subsurface fracture plane in the concrete ator just above the level of the reinforcement.The fracture plane,or delamination,may be localized or may extend over asubstantial area,especially if the concrete cover to the rein-forcement is small.It is not uncommon for more than onedelamination to occur on different planes between the concretesurface and the reinforcing steel.Delaminations are not visibleon the concrete surface.However,if repairs are not made,thedelaminations progress to open spalls and,with continuedcorrosion,eventually affect the structural integrity of the deck.1.2.2 The portion of concrete contaminated with excessivechlorides is generally structurally deficient compared withnon-contaminated concrete.Additionally,the chloride-contaminated concrete provides a pathway for the chloride ionsto initiate corrosion of the reinforcing steel.It is therefore ofparticular interest in bridge deck condition investigations tolocate not only the areas of active reinforcement corrosion,butalso areas of chloride-contaminated and otherwise deterioratedconcrete.1.3 This test method may not be suitable for evaluatingbridges with delaminations that are localized over the diameterof the reinforcement,or for those bridges that have cathodicprotection(coke breeze as cathode)installed on the bridge orfor which a conductive aggregate has been used in the asphalt(that is,blast furnace slag).This is because metals are perfectreflectors of electromagnetic waves,since the wave imped-ances for metals are zero.1.4 Since a precision estimate for this standard has not beendeveloped,the test method is to be used for research andinformational purposes only.Therefore,this standard shouldnot be used for acceptance or rejection of a material forpurchasing purposes.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 The text of this standard references notes and footnoteswhich provide explanatory material.These notes and footnotes(excluding those in tables and figures)shall not be consideredas requirements of the standard.1.7 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.Specific precautionary statements are given in Section 5.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.32 onBridges and Structures.Current edition approved Nov.1,2022.Published November 2022.Originallyapproved in 1997.Last previous edition approved in 2015 as D6087 08(2015)1.DOI:10.1520/D6087-22.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in