ACI 325 11R-2001 Accelerated Techniques for Concrete Paving《混凝土铺砌用加速技术》.pdf

1、ACI 325.11R-01 became effective January 3, 2001.Copyright 2001, 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, o

2、r recording for sound or visual reproduc-tion or for use in any knowledge or retrieval system or device, unless permission inwriting is obtained from the copyright proprietors.ACI Committee Reports, Guides, Standard Practices,and Commentaries are intended for guidance in planning,designing, executin

3、g, and inspecting construction. Thisdocument is intended for the use of individuals who arecompetent to evaluate the significance and limitations ofits content and recommendations and who will accept re-sponsibility for the application of the material it contains.The American Concrete Institute disc

4、laims any and all re-sponsibility for the stated principles. The Institute shallnot be liable for any loss or damage arising therefrom.Reference to this document shall not be made in con-tract documents. If items found in this document are de-sired by the Architect/Engineer to be a part of the contr

5、actdocuments, they shall be restated in mandatory languagefor incorporation by the Architect/Engineer.325.11R-1Accelerated Techniques for Concrete PavingACI 325.11R-01This report covers the state of the art of accelerated-concrete paving tech-niques, often referred to as “fast-track” concrete paving

6、. Accelerated-con-crete paving techniques are appropriate for roadways, airfield, and otherpaved surfaces where quick access is required. Considerations include plan-ning, concrete materials and properties, jointing and joint sealing, curingand temperature control, concrete strength testing, and ope

7、ning-to-traffic cri-teria. Applications and uses of accelerated-concrete paving are discussed.Keywords: accelerated paving; airports; admixtures; aggregates; cement;construction; concrete pavement; curing; fast-track paving; gradation;highways; intersections; joint sealing compound; jointing; nondes

8、tructivestrength testing; specifications; streets; temperature; opening-to-traffic.CONTENTSChapter 1Introduction, p. 325.11R-21.1General1.2Changes to construction specifications and processesChapter 2Project applications, p. 325.11R-22.1General2.2Highways and tollways2.3Streets2.4Intersections2.5Air

9、portsReported by ACI Committee 325Richard O. Albright Luis Amando Garcia James C. Mikulanec Raymond S. RollingsWilliam L. Arent Nader Ghafoori Paul E. Mueller Matthew W. RossJamshid M. Armaghani Jimmy D. Gillard Jon I. Mullarky Gene SapperWalter R. BarkerDennis W. Graber*Antonio Nanni Michel A. Sarg

10、iousBrian T. Bock W. Charles Greer Theodore L. Neff Milton R. SeesGlen Bollin Kathleen T. Hall Peter J. Nussbaum Kieran G. SharpDonald L. Brogna*Amir N. Hanna Emmanuel Owusu-AntwiJames M. Shilstone, Sr.*Archie F. Carter James C. Hawley Dipak T. Parekh Bernard J. SkarLawrence W. ColeMark K. Kaler Tho

11、mas J. Pasko, Jr.Shiraz D. Tayabji*Michael I. Darter Oswin Keifer, Jr. Ronald L. Peltz Alan H. TodresM. Nasser Darwish Starr D. Kohn Robert W. PiggotSuneel N. Vanikar*Norbert J. Delatte Ronald L. Larsen David W. Pittman Douglas W. WeaverDale H. Diulus Robert V. Lopez Steven A. Ragan David P. Whitney

12、Ralph L. Duncan*Gary R. Mass John L. Rice Dan G. ZollingerRobert J. Fluhr Tim McLaughlinTerry W. ShermanChairmanJack A. ScottSecretary*Member, Accelerated Rigid Paving Techniques Task Group.Chairman, Accelerated Rigid Paving Techniques Task Group.Note: ACI Committee 325 Associate Members Gerald F. V

13、oigt and William R. Hook also participated in the report preparation.ACI COMMITTEE REPORT 325.11R-2Chapter 3Planning, p. 325.11R-33.1Planning considerations3.2Lane rental3.3Partnering3.4Specifications3.5Innovative equipmentChapter 4Concrete materials, p. 325.11R-44.1Concrete mixture proportioning4.2

14、Cement4.3Supplementary cementitious materials4.4Air-entraining admixture4.5Water-reducing admixtures4.6Accelerating admixtures4.7Aggregate4.8WaterChapter 5Construction, p. 325.11R-95.1General5.2Curing and temperature management5.3Jointing and sealingChapter 6Nondestructive testing, p. 325.11R-136.1A

15、ppropriate methods6.2Maturity6.3Pulse-velocityChapter 7Traffic opening, p. 325.11R-147.1Strength criteria7.2Construction traffic7.3Public traffic7.4Aircraft trafficChapter 8References, p. 325.11R-168.1Referenced standards and reports8.2Cited references8.3Other referencesAppendixOpening to public tra

16、ffic, p. 325.11R-17CHAPTER 1INTRODUCTION1.1GeneralAirport authorities and road agencies face major challeng-es from increasing traffic volumes on existing airports, road-ways, and urban streets. Owners must repair or replacedeteriorated pavements while maintaining traffic on thesestructures. Traditi

17、onal pavement construction, repair, or re-placement solutions may no longer be universally acceptabledue to increasing public impatience with traffic interruption.Traditional solutions are especially inappropriate in urbanareas where congestion is severe. Accelerated constructiontechniques for portl

18、and cement concrete pavement resolvethese problems by providing quick public access to a high-quality, long-lasting pavement. Accelerated constructiontechniques are suitable for new construction, reconstruction,or resurfacing projects. Accelerated construction for con-crete paving is often referred

19、to as “fast-track” concrete pav-ing. Accelerated paving encompasses two classes ofactivities: technological methods to accelerate the rate ofstrength gain and contractual methods to minimize the con-struction time. Many methods exist to accelerate pavement construction.1Two traditional acceleration

20、methods are time incentives andpenalties for project completion. Agencies have been usingthese time-of-completion incentives for many years, and of-ten contractors will meet these requirements by lengtheningthe work day or increasing the size of construction crews.Using accelerated paving techniques

21、, a contractor often cancomplete a project without increasing crew size or changingnormal labor schedules.1.2Changes to construction specifications and processesTo build an accelerated paving project, both the contractorand the agency must make some changes to traditional con-struction specification

22、s and processes. Often, these involvehigh-early-strength concrete, but they also can include revis-ing opening-to-traffic criteria, construction staging, jointconstruction, and worker responsibilities. Table 1.2 suggestschanges to project components that can decrease construc-tion time.CHAPTER 2PROJ

23、ECT APPLICATIONS2.1GeneralAccelerated techniques for concrete paving allow trans-portation officials to consider concrete for projects thatTable 1.2Changes to project components useful to shorten concrete pavement construction time2Project Component Possible changesPlanningImplement partnering-based

24、 project management.Implement lane rental charges.Allow night construction.Allow contractor to use innovative equipment or procedures to expedite construction (for example, minimum-clearance machines, dowel inserters, and ultra-light saws).Specify more than one concrete mixture for varied strength d

25、evelopment.Provide options to contractors, not step-by-step procedures.Use time-of-completion incentives and disincen-tives.Concrete materialsTry different cement types (particularly Type III).Use helpful admixtures.Use a well-graded aggregate.Keep water-cementitious materials ratio (w/cm) below 0.4

26、3.Jointing andsealingAllow early-age sawing.Use dry-sawing blades.Use step-cut blades for single-pass joint sawing.Use a sealant that is unaffected by moisture or res-ervoir cleanliness.Concrete curing and temperatureSuggest blanket curing to aid strength gain when beneficial.Monitor concrete temper

27、ature and understand rela-tionship of ambient, subgrade, and mixture tem-perature on strength gain.Elevate concrete temperature before placement.Strength testingUse nondestructive methods to replace or supple-ment cylinders and beams for strength testing.Use concrete maturity or pulse velocity testi

28、ng to predict strength.Traffic openingcriterionRevise from a time criterion to a strength criterion. Channel early loads away from slab edges.Resist truck traffic.ACCELERATED TECHNIQUES FOR CONCRETE PAVING 325.11R-3might not otherwise be feasible because of lengthy concretecuring intervals. Some spe

29、cifications require cure intervalsfrom 5 to 14 days for conventional concrete mixtures.3Withaccelerated paving techniques, concrete can meet openingstrengths in less than 12 hours.2,4,52.2Highways and tollwaysMany highway agencies use accelerated techniques for con-crete paving techniques to expedit

30、e construction and easework-zone congestion. Major projects in Chicago and Denverhave shown how accelerated-concrete paving can decreaseconstruction time for urban and suburban roadways.6,7Tollway authorities lose revenue as a result of lane clo-sures because traffic delays cause many drivers to fin

31、d alter-native routes. Accelerated-concrete pavement minimizesrevenue loss by allowing earlier access at high-congestionareas like toll booths and interchanges.The need for accelerated techniques on rural highway orroad construction is more limited. A contractor may use ac-celerated techniques to sp

32、eed construction on portions of aproject to allow construction equipment on the pavementsooner than usual. The contractor also may use accelerated-concrete paving for the last portion of a project to speed finalopening to public vehicles. The Federal Highway Adminis-tration (FHWA) is encouraging all

33、 highway agencies to useaccelerated techniques for concrete paving to meet specialconstruction needs.22.3StreetsAccelerated paving technology also provides solutions forpublic access on residential and urban streets. Residentsalong suburban streets can usually gain access to their drive-ways within

34、24 hours.2.4IntersectionsIntersections pose major construction staging and traffic in-terruption challenges because they affect two or more streets.A unique project by the Iowa Department of Transportationinvolved the replacement of nine intersections using acceler-ated paving.8,9Using two concrete

35、mixtures and night con-struction, the contractor finished each intersection withoutdisrupting daily rush-hour traffic.9Reconstructing intersections one quadrant at a time allowstraffic to continue to use the roadways. With acceleratedconstruction techniques and quadrant construction, a con-tractor c

36、an pave the intersection in less than one week.Where it is feasible to close the entire intersection for a shorttime, a contractor can use accelerated paving techniques tocomplete reconstruction over a weekend.2.5AirportsOn airport aprons, runways, and taxiways, accelerated-con-crete paving speeds s

37、equential paving placements. Such pave-ment gains strength quickly and allows contractors to operateslipform equipment sooner on completed adjacent pavinglanes. The construction schedule is reduced by shortening thewait before paving interior lanes. Accelerated paving tech-niques also can speed reco

38、nstruction of cross-runway intersec-tions, runway extensions, and runway keel sections. This maybe necessary to maintain traffic at commercial airports or forthe national defense at military air bases. Accelerated-con-crete paving reduces the time that passenger loading gates areout of service at co

39、mmercial airports for apron reconstruction.CHAPTER 3PLANNING3.1Planning considerationsDeveloping a traffic-control plan before construction is es-sential for projects with high traffic volumes. The goal is toreduce the construction period and minimize traffic disrup-tion. An agency will benefit beca

40、use meeting this goal willreduce public complaints, business impacts, user-delaycosts, and traffic-control costs. The contractor will benefit byreducing workers exposure to accidents and reducing thetime for which equipment is committed to a project.Planners should include accelerated paving techniq

41、ueswhen assessing project feasibility or when developing con-struction staging plans. Table 3.1 lists other issues thatshould be considered when planning an accelerated project.One common method specifiers use to ensure project com-pletion by a certain date is through a time-of-completioncontract th

42、at offers monetary incentives and penalties to thecontractor. The agency specifies the completion date and thedaily incentive or penalty value. The contractor earns the in-centive for completing the project before the deadline orpays the penalty for finishing late. These arrangements areeasily under

43、stood and usually ensure timely construction.Certain new lane-rental contracting techniques may be moreuseful for accelerated-concrete pavement construction, be-cause they encourage more contractor flexibility and innova-tion than a completion-time contract.3.2Lane rentalLane rental is an innovative

44、 contracting practice that en-courages contractors to lessen the construction impact onroad users.10,11There are three basic lane rental methods:cost-plus-time bidding; continuous site rental; and lane-by-lane rental. For each method, the agency must determine arental charge for use of all or part o

45、f the roadway by thecontractor. The rental charge usually coincides with theuser cost estimate for delays during project construction.The user costs vary for each project and, consequently, soshould rental charges. Computer programs are available todetermine work zone user costs.12Table 3.1Important

46、 considerations for planning accelerated-concrete paving projectsImportant planning considerationsAccess for local trafficLocal business disruptionUtility workConstruction equipment access and operationAvailability of suitable materialsWork-zone safetyPavement edge drop-off requirementsCrossovers th

47、at disrupt both directions of trafficDetour routes that can suffer damage and congestion from prolonged construction zone detoursUsing fast-track concrete near the end of one days paving can facilitate next-day startupACI COMMITTEE REPORT 325.11R-4Not all projects warrant lane-rental assessments. A

48、lane-rental contract requires special contracting terms and is mostsuitable for large projects where construction congestionmanagement is critical. To reduce congestion on smallerprojects, an agency can modify concrete materials and con-struction specifications to decrease road or lane closure time.

49、Contract management and record keeping on lane-rentalprojects can be difficult. Accounting for partial completionof portions of a project can be confusing. Therefore, it is im-portant for contract language to cover these situations.Cost-plus-time bidding (also called “A+B bidding”) di-vides each contractors bid into two parts: the constructioncost and the time cost.10,11Along with construction costs,the contractor must include an estimate of the number ofdays necessary to complete the project in the bid. The agencymultiplies the ti