ACI 345R-2011 Guide for Concrete Highway Bridge Deck Construction.pdf

1、ACI 345R-11Reported by ACI Committee 345Guide for Concrete HighwayBridge Deck ConstructionGuide for Concrete Highway Bridge Deck ConstructionFirst PrintingSeptember 2011ISBN 978-0-87031-410-0American Concrete InstituteAdvancing concrete knowledgeCopyright by the American Concrete Institute, Farmingt

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10、tandards and committee reports are gathered together in the annually revised ACI Manual ofConcrete Practice (MCP).American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgACI 345R-11 supersedes 345R-91 and was adopted and

11、published September 2011.Copyright 2011, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by anymeans, including the making of copies by any photo process, or by electronic ormechanical device, printed, written, or oral, or recording for sound o

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13、his document is intended for theuse of individuals who are competent to evaluate thesignificance and limitations of its content and recommendationsand who will accept responsibility for the application of thematerial it contains. The American Concrete Institute disclaimsany and all responsibility fo

14、r the stated principles. The Instituteshall not be liable for any loss or damage arising therefrom.Reference to this document shall not be made in contractdocuments. If items found in this document are desired by theArchitect/Engineer to be a part of the contract documents, theyshall be restated in

15、mandatory language for incorporation bythe Architect/Engineer.Guide for Concrete Highway Bridge Deck ConstructionReported by ACI Committee 345ACI 345R-11The service-life performance of concrete bridge decks, including maintenance,repair, and rehabilitation needs, is directly related to the care exer

16、cisedfrom the preconstruction through post-construction period. This guideprovides recommendations for bridge deck construction based onconsiderations of durability, concrete materials, reinforcement, placing,finishing and curing, and overlays.Keywords: admixtures; aggregate; air entrainment; bridge

17、 decks; concretecuring; concrete finishing; concrete overlays; concrete placing; cracking;durability; polymer concrete; reinforcing bars; scaling; shrinkage; skidresistance.CONTENTSChapter 1Introduction and scope, p. 21.1Introduction1.2ScopeChapter 2Definitions, p. 22.1DefinitionsChapter 3Design and

18、 durability considerations,p. 23.1General3.2Concrete and reinforcement materials3.3Positive protective systems3.4Arrangement and cover of reinforcement3.5Deck thickness3.6Deck drainage3.7Joint-forming materials and locations3.8Types and causes of deck crackingGerald H. Anderson Dena L. Guth Johan L.

19、 Silfwerbrand Paul J. St. JohnMichael C. Brown Alan B. Matejowsky Michael M. Sprinkel Jerzy Z. ZemajtisRobert J. Gulyas*Harold R. Sandberg*Deceased.Richard E. WeyersChairPaul D. CarterSecretaryConsulting membersJames C. Anderson Martin E. IornsByron T. Danley Yash Paul VirmaniFouad H. Fouad Jeffrey

20、P. WoutersAllan C. Harwood2 GUIDE FOR CONCRETE HIGHWAY BRIDGE DECK CONSTRUCTION (ACI 345R-11)American Concrete Institute Copyrighted Materialwww.concrete.orgChapter 4Concrete materials, p. 104.1General4.2Concrete-making materials4.3Chemical admixtures4.4Effects on concrete properties4.5Workability a

21、nd consistency4.6Bleeding4.7Air content4.8Setting time4.9Shrinkage4.10Durability4.11Strength4.12Skid resistanceChapter 5Reinforcement, p. 175.1General considerations5.2Reinforcement placement5.3Reinforcement supports and ties5.4Concrete cover over reinforcement5.5Cleanliness5.6Reinforcement typeChap

22、ter 6Placing, finishing, and curing, p. 226.1Placing6.2Finishing6.3CuringChapter 7Overlays, p. 317.1Scope7.2Need for overlays7.3Required properties of overlays7.4Types of overlays7.5Design considerations7.6Construction considerations7.7Other considerationsChapter 8References, p. 358.1Referenced stan

23、dards and reports8.2Cited referencesCHAPTER 1INTRODUCTION AND SCOPE1.1IntroductionThe deck of a highway bridge serves both structural andfunctional purposes for the structure. As a structuralcomponent, it provides the load path to safely transfer forcesfrom wheel loads to the supporting superstructu

24、re andsubstructure elements. It may also contribute, throughcomposite action, to the performance of primary superstructurecomponents. Equally, the construction and condition of adeck directly impacts serviceability or the ability of thestructure to safely and efficiently carry highway traffic byprov

25、iding smoothness, skid resistance, and resistance todeflections under wheel loads. The riding surface of ahighway bridge deck should provide a continuation of thepavement segments that it connects. The surface should befree from characteristics or profile deviations that impartobjectionable or unsaf

26、e riding qualities. The desirable qualitiesshould persist with minimum maintenance throughout theprojected service life of the structure.Roughness, cracking, spalling, scaling, and poor skidresistance are defects that result when the many details thatinfluence their occurrence are not given sufficie

27、nt attention.Recognition of the interaction of design, materials, andconstruction practices, as well as environmental factors, is theimportant first step in achieving smooth and durable decks.Many decks remain smooth and free from surface deterio-ration and retain skid resistance for many years. Whe

28、ndeficiencies occur, they usually take one of the formsdescribed in this guide. The contribution of various aspectsof deck construction to defects is discussed and guidelinesbased on theory and experience presented that should reducethe probabilities of occurrence to acceptable levels.1.2ScopeThis g

29、uide presents considerations to take in the designand a summary of construction practices for conventionallyreinforced concrete highway bridge decks. Such decks aretypically supported by multiple simple- or continuous-spansteel or prestressed concrete girders, or integral reinforcedconcrete members.

30、 The service-life performance of concretebridge decks, including maintenance, repair, and rehabilitationneeds, is directly related to the care exercised frompreconstruction through the post-construction period.Recommendations are presented for design and durabilityconsiderations, concrete materials,

31、 reinforcement, placing,finishing and curing, and the use of overlays.Although some performance and durability factorsdiscussed may be applicable, design and construction ofprestressed bridge decks are presently beyond the scope ofthis guide. Thus, prestressing steel is not included in thereinforcem

32、ent section. Guidance for the design ofprestressed bridge decks is being developed elsewhere(Swartz and Schokker 2008).CHAPTER 2DEFINITIONS2.1DefinitionsACI provides a comprehensive list of definitions throughan online resource, “ACI Concrete Terminology,” athttp:/terminology.concrete.org. Definitio

33、ns provided hereincomplement that resource.crack, reflectivea crack that forms in a bonded overlayor wearing course caused by upward extension of movingcrack or joint in the substrate.washboardingundulations in the finished surface of adeck that cause vibrations of undesirable frequency andamplitude

34、 in passing vehicles.CHAPTER 3DESIGN AND DURABILITY CONSIDERATIONS3.1GeneralChapter 3 emphasizes design factors that may affect theresistance of a bridge deck to chemical and environmentalexposure, including potential for freezing and thawing,deleterious chemical reactions with concrete constituents

35、, orchloride-induced corrosion damage. The design considerationsof this chapter are not concerned with the structural analysisof the bridge deck. Structural aspects of the design, however,can have implications in the development of internal stressesGUIDE FOR CONCRETE HIGHWAY BRIDGE DECK CONSTRUCTION

36、 (ACI 345R-11) 3American Concrete Institute Copyrighted Materialwww.concrete.organd subsequent cracking in bridge decks, which may negativelyimpact durability. The items discussed in this chapter aregenerally within the purview of the bridge designer, andshould receive due consideration.3.2Concrete

37、and reinforcement materialsAlthough the specific topics of material selection forconcrete mixture proportioning and bridge deck reinforce-ment are covered in greater detail in Chapters 4 and 5,respectively, it is important to emphasize the influence ofmaterial selection during the design process on

38、the long-termdurability of a bridge deck. Most modern bridge deck designsgenerally employ some strategy for deterring corrosion andenhancing exposure-related durability. These may include theuse of epoxy-coated, galvanized, or metallic-clad reinforce-ment; alternative reinforcement materials such as

39、 variousgrades of stainless steel, specialized steel alloy formulations; orfiber-reinforced polymer (FRP) reinforcement.The use of better-quality concrete mixtures has gainedfavor, either separately from, or in conjunction with,alternative reinforcement strategies. Such strategies mayinclude minimiz

40、ing the water-cementitious material ratio(w/cm) of a concrete mixture or the use of mineral admixtures,such as fly ash, silica fume, slag cement, or metakaolin, toreduce permeability characteristics of the concrete. Manyother admixtures are commercially available to addressworkability and placement

41、characteristics, resistance tofreezing and thawing, and increased corrosion resistance.Other products are available to reduce susceptibility toplastic and drying shrinkage.Careful consideration should be given to the selection ofdeck materials. One common myth is that compressivestrength is the sing

42、le most important factor in specifyingquality deck concrete. In fact, concrete bridge deckscomposed of concrete with excessively high compressivestrength tend to be less flexible, have greater shrinkagepotential, and have less ability to redistribute load andthermal- or shrinkage-induced strains. Th

43、e result is a greatertendency toward cracking, which leads to premature deteriora-tion from the ingress of moisture and aggressive chemicals,such as deicing salts. Recently, many agencies have consideredperformance-based specifications that rely more on measuresof permeability than strength as crite

44、ria for acceptance.Alternatively, reinforcing materials such as FRP bars,which are not affected by chlorides, can be considered viablealternatives to ferrous reinforcing bars. The use of FRP barsis governed by the American Association of State HighwayTransportation Officials (AASHTO) LRFD design gui

45、delines(AASHTO 1998) and by the Canadian Highway BridgeDesign Code (CAN/CSA-S6-06) (Canadian StandardsAssociation 2006).3.3Positive protective systems3.3.1 OverlaysThe common forms of bridge deck deteri-oration, such as scaling, some types of cracking, and surfacespalling, generally occur within the

46、 top 2 in. (50 mm) of adeck. Improper concrete placing and finishing practices oftenresult in a lower-quality concrete in this area. Because it issubjected to the most severe exposure and service conditions,the top portion of the deck slab should have the best possibleconcrete quality. Consideration

47、 should be given to placing anoverlay on the bridge deck when it is constructed. Manydifferent types of overlays have been used successfully.Chapter 7 discusses several types of overlays in detail.3.3.2 Other positive protective systemsBecause of thehigh cost of repairing corrosion-induced damage, s

48、everaldifferent protective systems are being used for bridge decksin severe deicing salt areas and for structures in marineenvironments. Other systems used to enhance durability orprotect decks, some of which have been mentioned already,may include:1. High-performance concretes that employ fly ash,

49、silicafume, and slag cement as mineral additives for reducedpermeability and protection against sulfate attack andalkali-silica reaction (ASR);2. Shrinkage-compensating cements or shrinkage-reducing admixtures (SRA) in concrete for crackreduction;3. Calcium nitrite, or other (anodic) corrosion-inhibitingadmixtures, for increasing the threshold value ofchloride concentration required for corrosion;4. Waterproofing membranes with or without a bituminousconcrete wearing surface for protection against chlorideion penetration;5. Pa