ACI 304R-2000 Guide for Measuring Mixing Transporting and Placing Concrete《测量、搅拌、运输和浇筑混凝土指南》.pdf

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1、ACI 304R-00(Reapproved 2009)Reported by ACI Committee 304Guide for Measuring, Mixing,Transporting, and Placing ConcreteGuide for Measuring, Mixing, Transporting, and Placing ConcreteISBN 978-0-87031-308-0American Concrete InstituteAdvancing concrete knowledgeCopyright by the American Concrete Instit

2、ute, Farmington Hills, MI. All rights reserved. This materialmay not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or otherdistribution and storage media, without the written consent of ACI.The technical committees responsible for ACI committee reports and

3、standards strive to avoid ambiguities,omissions, and errors in these documents. In spite of these efforts, the users of ACI documents occasionallyfind information or requirements that may be subject to more than one interpretation or may beincomplete or incorrect. Users who have suggestions for the

4、improvement of ACI documents arerequested to contact ACI. Proper use of this document includes periodically checking for errata atwww.concrete.org/committees/errata.asp for the most up-to-date revisions.ACI committee documents are intended for the use of individuals who are competent to evaluate the

5、significance and limitations of its content and recommendations and who will accept responsibility for theapplication of the material it contains. Individuals who use this publication in any way assume all risk andaccept total responsibility for the application and use of this information.All inform

6、ation in this publication is provided “as is” without warranty of any kind, either express or implied,including but not limited to, the implied warranties of merchantability, fitness for a particular purpose ornon-infringement.ACI and its members disclaim liability for damages of any kind, including

7、 any special, indirect, incidental,or consequential damages, including without limitation, lost revenues or lost profits, which may resultfrom the use of this publication.It is the responsibility of the user of this document to establish health and safety practices appropriate tothe specific circums

8、tances involved with its use. ACI does not make any representations with regard tohealth and safety issues and the use of this document. The user must determine the applicability of allregulatory limitations before applying the document and must comply with all applicable laws and regulations,includ

9、ing but not limited to, United States Occupational Safety and Health Administration (OSHA) healthand safety standards.Order information: ACI documents are available in print, by download, on CD-ROM, through electronicsubscription, or reprint and may be obtained by contacting ACI.Most ACI standards a

10、nd 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 304R-00 supersedes ACI 304R-89 and became effective Janua

11、ry 10, 2000.Copyright 2000, 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 or visualrepro

12、duction or for use in any knowledge or retrieval system or device, unlesspermission in writing is obtained from the copyright proprietors.304R-1ACI Committee Reports, Guides, Standard Practices, andCommentaries are intended for guidance in planning,designing, executing, and inspecting construction.

13、Thisdocument is intended for the use of individuals who arecompetent to evaluate the significance and limitations of itscontent and recommendations and who will acceptresponsibility for the application of the material it contains.The American Concrete Institute disclaims any and allresponsibility fo

14、r the stated principles. The Institute shall notbe 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.This guide presents information on the handling, measuring, and batchingof all the materials used in making normalweight, lightweight structural,and heavyweight concrete. It covers both weight and volumetricmeasuring; mixing in central mi

16、xture plants and truck mixers; and concreteplacement using buckets, buggies, pumps, and conveyors. Underwaterconcrete placement and preplaced aggregate concrete are also covered inthis guide, as well as procedures for achieving good quality concrete incompleted structures.Keywords: batching; continu

17、ous mixing; conveying; heavyweight concretes;lightweight concretes; materials handling; mixing; placing; preplacedaggregate concrete; pumped concrete; tremie concrete; volumetric measuring.CONTENTSChapter 1Introduction, p. 304R-21.1Scope1.2Objective1.3Other considerationsChapter 2Control, handling,

18、and storage of materials, p. 304R-32.1General considerations2.2AggregatesGuide for Measuring, Mixing, Transporting,and Placing ConcreteReported by ACI Committee 304ACI 304R-00(Reapproved 2009)Neil R. GuptillChairmanDavid J. Akers John C. King Kenneth L. SaucierCasimir Bognacki Gary R. Mass James M.

19、Shilstone, Jr.James L. Cope Patrick L. McDowell Ronald J. StickelMichael R. Gardner Dipak T. Parekh William X. SypherDaniel J. Green Roger J. Phares J.A. Tony TinkerBrian Hanlin James S. Pierce Robert E. TobinTerence C. Holland Paul E. Reinhart Joel B. TuckerThomas A. Johnson Royce J. Rhoads Kevin W

20、olf2.3Cement2.4Ground slag and pozzolans2.5Admixtures2.6Water and ice2.7Fiber reinforcementChapter 3Measurement and batching, p. 304R-63.1General requirements3.2Bins and weigh batchers3.3Plant type3.4Cementitious materials3.5Water and ice measurement3.6Measurement of admixtures3.7Measurement of mate

21、rials for small jobs3.8Other considerationsChapter 4Mixing and transporting, p. 304R-104.1General requirements4.2Mixing equipment4.3Central-mixed concrete4.4Truck-mixed concrete4.5Charging and mixing4.6Mixture temperature4.7Discharging4.8Mixer performance4.9Maintenance4.10General considerations for

22、transporting concrete4.11Returned concrete304R-2 ACI COMMITTEE REPORTChapter 5Placing concrete, p. 304R-145.1General considerations5.2Planning5.3Reinforcement and embedded items5.4Placing5.5Consolidation5.6Mass concretingChapter 6Forms, joint preparation, and finishing, p. 304R-196.1Forms6.2Joint pr

23、eparation6.3Finishing unformed surfacesChapter 7Preplaced-aggregate concrete,p. 304R-217.1General considerations7.2Materials7.3Grout proportioning7.4Temperature control7.5Forms7.6Grout pipe systems7.7Coarse aggregate placement7.8Grout mixing and pumping7.9Joint construction7.10Finishing7.11Quality c

24、ontrolChapter 8Concrete placed under water,p. 304R-258.1General considerations8.2Materials8.3Mixture proportioning8.4Concrete production and testing8.5Tremie equipment and placement procedure8.6Direct pumping8.7Concrete characteristics8.8Precautions8.9Special applications8.10Antiwashout admixturesCh

25、apter 9Pumping concrete, p. 304R-289.1General considerations9.2Pumping equipment9.3Pipeline and accessories9.4Proportioning pumpable concrete9.5Field practice9.6Field controlChapter 10Conveying concrete, p. 304R-3210.1General considerations10.2Conveyor operation10.3Conveyor design10.4Types of concre

26、te conveyors10.5Field practiceChapter 11Heavyweight and radiation-shielding concrete, p. 304R-3511.1General considerations11.2Materials11.3Concrete characteristics11.4Mixing equipment11.5Formwork 11.6Placement 11.7Quality controlChapter 12Lightweight structural concrete,p. 304R-3612.1General conside

27、rations12.2Measuring and batching12.3Mixing12.4Job controlsChapter 13Volumetric-measuring and continuous-mixing concrete equipment,p. 304R-4013.1General considerations13.2Operations13.3Fresh concrete propertiesChapter 14References, p. 304R-4114.1Referenced standards and reports14.2Cited referencesCH

28、APTER 1INTRODUCTION1.1ScopeThis guide outlines procedures for achieving good results inmeasuring and mixing ingredients for concrete, transporting itto the site, and placing it. The first six chapters are general andapply to all types of projects and concrete. The following fourchapters deal with pr

29、eplaced-aggregate concrete, underwaterplacing, pumping, and conveying on belts. The concludingthree chapters deal with heavyweight, radiation-shieldingconcrete, lightweight concrete, and volumetric-measuring andcontinuous-mixing concrete equipment.1.2ObjectiveWhen preparing this guide, ACI Committee

30、 304 followedthis philosophy:Progress in improvement of concrete construction isbetter served by the presentation of high standardsrather than common practices;In many, if not most, cases, practices resulting in theproduction and placement of high-quality concrete can beperformed as economically as

31、those resulting in poorconcrete. Many of the practices recommended in thisdocument improve concrete uniformity as well as quality,yielding a smoother operation and higher productionrates, both of which offset potential additional cost; andAnyone planning to use this guide should have a basicknowledg

32、e of the general practices involved in concretework. If more specific information on measuring,mixing, transporting, and placing concrete is desired,the reader should refer to the list of references given atthe end of this document, and particularly to the workof the U.S. Bureau of Reclamation (1981

33、), the U.S.Department of Commerce (1966), the Corps of Engi-neers (1994a), ASTM C 94, ACI 311.1R, and ACI 318.To portray more clearly certain principles involved inachieving maximum uniformity, homogeneity, andquality of concrete in place, figures that illustrate goodand poor practices are also incl

34、uded in this guide. MEASURING, MIXING, TRANSPORTING, AND PLACING CONCRETE 304R-31.3Other considerationsAll who are involved with concrete work should know theimportance of maintaining the unit water content as low aspossible and still consistent with placing requirements(Mielenz 1994; Lovern 1966).

35、If the water-cementitiousmaterials ratio (w/cm) is kept constant, an increase in unitwater content increases the potential for drying-shrinkagecracking, and with this cracking, the concrete can lose aportion of its durability and other favorable characteristics,such as monolithic properties and low

36、permeability.Indiscriminate addition of water that increases the w/cmadversely affects both strength and durability.The more a form is filled with the right combination of solidsand the less it is filled with water, the better the resultingconcrete will be. Use only as much cement as is required toa

37、chieve adequate strength, durability, placeability, workability,and other specified properties. Minimizing the cement contentis particularly important in massive sections subject torestraint, as the temperature rise associated with the hydrationof cement can result in cracking because of the change

38、involume (ACI 207.1R and 207.2R). Use only as much water andfine aggregate as is required to achieve suitable workability forproper placement and consolidation by means of vibration.CHAPTER 2CONTROL, HANDLING,AND STORAGE OF MATERIALS2.1General considerationsCoarse and fine aggregates, cement, pozzol

39、ans, and chem-ical admixtures should be properly stored, batched, andhandled to maintain the quality of the resulting concrete.2.2AggregatesFine and coarse aggregates should be of good quality,uncontaminated, and uniform in grading and moisture content.Unless this is accomplished through appropriate

40、 specifica-tions (ASTM C 33) and effective selection, preparation, andhandling of aggregates (Fig. 2.1), the production of uniformconcrete will be difficult (Mielenz 1994; ACI 221R).2.2.1 Coarse aggregateThe coarse aggregate should becontrolled to minimize segregation and undersized material.The fol

41、lowing sections deal with prevention of segregationand control of undersized material.2.2.1.1 SizesA practical method of minimizing coarseaggregate segregation is to separate the material into severalsize fractions and batch these fractions separately. As therange of sizes in each fraction is decrea

42、sed and the numberof size separations is increased, segregation is furtherreduced. Effective control of segregation and undersizedmaterials is most easily accomplished when the ratio ofmaximum-to-minimum size in each fraction is held to notmore than four for aggregates smaller than 1 in. (25 mm) and

43、to two for larger sizes. Examples of some appropriate aggre-gate fraction groupings follow:Example 1Sieve designationsNo. 8 to 3/8 in. (2.36 to 9.5 mm)No. 4 to 1 in. (4.75 to 25.0 mm)3/4 to 1-1/2 in. (19.0 to 37.5 mm)Example 2Sieve designationsNo. 4 to 3/4 in. (4.75 to 19.0 mm)3/4 to 1-1/2 in. (19.0

44、 to 37.5 mm)1-1/2 to 3 in. (37.5 to 75 mm)3 to 6 in. (75 to 150 mm)2.2.1.2 Control of undersized materialUndersizedmaterial for a given aggregate fraction is defined as materialthat will pass a sieve having an opening 5/6 of the nominalminimum size of each aggregate fraction (U.S. Bureau ofReclamati

45、on 1981). In Example 2 in Section 2.2.1.1, it wouldbe material passing the following sieves: No. 5 (4.0 mm),5/8 in. (16.0 mm), 1-1/4 in. (31.5 mm), and 2-1/2 in. (63 mm).For effective control of gradation, handling operations that donot increase the undersized materials in aggregates significantlybe

46、fore their use in concrete are essential (Fig. 2.1 and 2.2). Thegradation of aggregate as it enters the concrete mixer shouldbe uniform and within specification limits. Sieve analyses ofcoarse aggregate should be made with sufficient frequency toensure that grading requirements are met. When two or

47、moreaggregate sizes are used, changes may be necessary in theproportions of the sizes to maintain the overall grading of thecombined aggregate. When specification limits for gradingcannot be met consistently, special handling methods shouldbe instituted. Materials tend to segregate during transporta

48、tion,so reblending may be necessary. Rescreening the coarseaggregate as it is charged to the bins at the batch plant toremove undersized materials will effectively eliminate unde-sirable fines when usual storage and handling methods arenot satisfactory. Undersized materials in the smaller coarseaggr

49、egate fractions can be consistently reduced to as low as2% by rescreening (Fig. 2.2). Although rescreening is effectivein removing undersized particles, it will not regrade segregatedaggregates.2.2.2 Fine aggregate (sand)Fine aggregate should becontrolled to minimize variations in gradation, giving specialattention to keeping finer fractions uniform and exercisingcare to avoid excessive removal of fines during processing.If the ratio of fine-to-coarse aggregate is adjusted in accor