ACI 549 1R-1993 Guide for the Design Construction and Repair of Ferrocement《钢丝网水泥的设计、施工和维修指南》.pdf

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1、ACI 549.1R-93Guide for the Design, Construction, (Reapproved 2009)and Repair of FerrocementReported by ACI Committee 549Gordon B. Batson*ChairmanPerumalsamy N. Balaguru*Jose O. CastroAntonio J. GuerraMartin E. Iorns*Colin D. JohnstonAntoine E. NaamanJames P. RomualdiSurendra P. ShahRonald F. Zollo*S

2、ecretary(former Chairman) *Narayan SwamyBen L. TilsenRobert B. WilliamsonRogerio C. Zubieta* Principal authorsThe following associate members of Committee 549 contributed to the preparation of this report: Shuaib H. Ahmad, Dougla s Alexander, Antonio Nanni, RicardoP. Pama, P. Paramasivam, Sherwood P

3、. Prawel, and Andrei M. Reinhorn.Members of the Committee voting on the 1993 revisions:P.N. BalaguruChairmanM. ArockiasamyNemkumar BanthiaGordon B. BatsonJose O. CastroJames I. DanielDavid M. GaleAntonio J. GuerraLloyd HackmanMartin E. IornsColin D. JohnstonMohammad MansurJohn L MulderAntoine E. Naa

4、manAntonio NanniD.V. ReddyJames P. RomualdiThis guide supplements two earlier publications (ACI 549R, State-of-the-Art Report of Ferrocement, and SP-61, Ferrocement-Materials andApplications). It provides technical information on materials and materialselection, design criteria and approaches, const

5、ruction methods, main-tenance and repair procedures, and testing. The objectives are to promotethe more effective use of ferrocement in terrestrial structures, providearchitects and engineers with the necessary tools to specify, and use ferro-cement, and provide owners or their representutives with

6、a reference docu-ment to check the acceptability of ferrocement alternative in a given ap-plication.Keywords: admixtures; cements; composite materials; construction; constructionmaterials; ferrocement; fibers; flexural strength, maintenance; metals; modulus ofelasticity; reinforced concrete; reinfor

7、cing materials; repairs; structural design;tension tests; welded wire fabric.CONTENTSChapter l-General, pg. 549.1R-2ACI Committee Reports, Guides, Standard Practices, andCommentaries are intended for guidance in designing, plan-ning, executing, or inspecting construction and in preparingspecificatio

8、ns. References to these documents shall not bemade in the Project Documents. If items found in thesedocuments are desired to be a part of the Project Docu-ments, they should be phrased in mandatory language andincorporated into the Project Documents.Parviz SoroushianSecretarySurendra P. ShahNarayan

9、SwamyBen L. TilsenMethi WecharatanaRobert B. WilliamsonRobert C. ZellersRonald F. ZolloRogerio C. Zubietal.l-Scope1.2-Approval to use proceduresChapter 2-Terminology, pg. 549.lR-22.1-Reinforcement parameters2.2-Notation2.3-DefinitionsChapter 3-Materials, pg. 549.1R-43.1-Matrix3.2-ReinforcementChapte

10、r 4-Design, pg. 549.1R.84.1-Design methods4.2-Strength requirements4.3-Service load design4.4-Serviceability4.5-Particular design parametersACI 549.lR-93 supersedes ACI 549.1R-88 and became effective November 1,1993.Copyright 0 1988, American Concrete Institute.All rights reserved including rights o

11、f reproduction and use in any form or byany means, including the making of copies by any photo process, or by any elec-tronic or mechanical device, printed, written, or oral, or recording for sound orvisual reproduction or for use in any knowledge or retrieval system or device,unless permission in w

12、riting is obtained from the copyright proprietors.549.1R-l549.1R-2 ACI COMMITTEE REPORT4.6-Examples4.7-Design aidsChapter 5-Fabrication, pg. 549.1R-115.1-General requirements5.2-Construction methodsChapter 6-Maintenance and repair, pg. 549.lR-156.1-Introduction6.2-Blemish and stain removal6.3-Protec

13、tive surface treatments6.4-Damage repair6.5-Repair materials6.6-Repair procedureChapter 7-Testing, pg. 549.lR-207.1-Test methodsChapter 8-References, pg. 549.1R-228.1-Recommended references8.2-Cited referencesAppendix A-Calculation of volume fraction of rein-forcement, pg. 549.1R-25Appendix B-Flexur

14、al strength analysis of ferrocementsections, pg. 549.1R-25Appendix C-SimpIified design aids, pg. 549,1R-28Appendix D-Surface treatment for ferrocement struc-tures attacked by commonly used chemicals, pg. 549.1R-29CHAPTER l-GENERALl.l-ScopeThis guide is based on technical information as-sembled b y A

15、CI Committee 549, Ferrocement, from cur-rent practice, developments, and advances in the field offerrocement around the world. It represents a practicalsupplement to the state-of-the-art report (ACI 549R)published earlier by the committee. The guide coversmaterials for ferrocement, materials selecti

16、on, and stan-dards; design criteria and approaches; construction meth-ods; maintenance and repair procedures; and testing.The objectives of this guide are to promote the effec-tive use of ferrocement in terrestrial structures, providearchitects and engineers with the necessary tools to spe-cify and

17、use ferrocement, and provide owners or their re-presentatives with a reference document to check theacceptability of a ferrocement alternative in a givenapplication. This guide is consistent with ACI BuildingCode Requirements for Reinforced Concrete (ACI 318)except for the special characteristics of

18、 ferrocement, suchas reinforcement cover and limits on deflection.Ferrocement is a form of reinforced concrete usingclosely spaced multiple layers of mesh and/or small-diameter rods completely infiltrated with, or encapsul-ated, in mortar. The most common type of reinforcementis steel mesh. Other ma

19、terials such as selected organic,natural, or synthetic fibers may be combined with metal-lic mesh. This guide addresses only the use of steel rein-forcement in a hydraulic cement mortar matrix.Applications of ferrocement are numerous, especiallyin structures or structural components where self-help

20、orlow levels of skills are required. Besides boats andmarine structures, ferrocement is used for housing units,water tanks, grain silos, flat or corrugated roofing sheets,irrigation channels, and the like (see ACI 549R).1.2-Approval for use in design and constructionUse of ferrocement and the proced

21、ures covered in thisguide may require approval by the authority or govern-mental agency having jurisdiction over the project.CHAPTER 2-TERMINOLOGY2.1-Reinforcing parametersThree parameters are commonly used in characterizingthe reinforcement in ferrocement applications: the vol-ume fraction, the spe

22、cific surface of reinforcement, andthe effective modulus of the reinforcement.2.1.1 Volume fraction of reinforcement Vf- Vfis thetotal volume of reinforcement divided by the volume ofcomposite (reinforcement and matrix). For a compositereinforced with meshes with square openings, Vf is equal-ly divi

23、ded into Vfland Vftfor the longitudinal and trans-verse directions, respectively. For other types of rein-forcement, such as expanded metal, Vfland Vftmay beunequal. Examples of computation of Vf are shown inAppendix A.2.1.2 Specific surface of reinforcement Sr- Sris the totalbonded area of reinforc

24、ement (interface area or area ofthe steel that comes in contact with the mortar) dividedby the volume of composite. Sris not to be confused withthe surface area of reinforcement divided by the volumeof reinforcement. For a composite using square meshes,Sris divided equally into Srland Srtin the long

25、itudinaland transverse directions, respectively.For a ferrocement plate of width b and depth h, thespecific surface of reinforcement can be computed from:cS0=7tbh(2-1)in which x0 is the total surface area of bonded rein-forcement per unit length.2.1.3 Relation between Srand Vf- The relation betweenS

26、rand Vf when square-grid wire meshes are used is4vSf=-fdbFERROCEMENT 549.1R-3where dbis the diameter of the wire . For other types ofreinforcement, such as expanded metal , Srland Srtmaybe unequal.2.1.3 Effective modulus of the reinforcement -Althoughthe definitions of most ferrocement properties ar

27、e thesame as for reinforced concrete, one property that maybe different is the effective modulus of the reinforcingsystem Er. This is because the elastic modulus of a mesh(steel or other) is not necessarily the same as the elasticmodulus of the filament (wire or other) from which it ismade. In a wov

28、en steel mesh, weaving imparts an undul-ating profile to the wires. When tested in tension, thewoven mesh made from these wires stretches more thana similar welded mesh made from identical straight wires.Hence, the woven mesh behaves as if it has a lower elas-tic modulus than that of the steel wires

29、 from which it ismade.In addition, when a woven mesh is embedded in amortar matrix and tends to straighten under tension, thematrix resists the straightening, leading to a form oftension stiffening .A similar behavior occurs withexpanded metal mesh (lath) and hexagonal mesh. Toaccount for the above

30、effects, the term “effective modulusof the reinforcing system ” Eris used. For welded steelmeshes, Ermay be taken equal to the elastic modulus ofthe steel wires; for other meshes , Ermay be determinedfrom tensile tests on the ferrocement composite as ex-plained in Chapter 7. Design values for common

31、 meshesused in ferrocement are recommended in Chapter 4.2.2-NotationAc =A=SAsi -b=c=d“ =db=di=cross-sectional area of ferrocement compositetotal effective cross-sectional area of rein-forcement in the direction consideredA, = f: As ii=leffective cross-sectional area of reinforcementof mesh layer i i

32、 n the direction consideredwidth of ferrocement sectiondistance from extreme compression fiber toneutral axisclear cover of mortar over first layer of meshdiameter or equivalent diameter of reinforce-ment useddistance from extreme compression fiber tocentroid of reinforcing laye r ielastic modulus o

33、f mortar matrixelastic modulus of cracked ferrocement in ten-sion (slope of the stress-strain curve in thecracked elastic state)effective modulus of the reinforcing systemelastic modulus of steel reinforcementspecified compressive strength of mortarstress in reinforcing layer istrength of mesh reinf

34、orcement or reinforcingbarsf=YhM=nN =n N =nr=s =Sr =Srl=S=rtV =fVfi=V =flV =ftPI =rl=772 =rlt =rl =c =cul . =CZEy =I:0 -Q =o-=cuyield strength of mesh reinforcement or rein-forcing barsthickness of ferrocement sectionnominal moment strengthnominal tensile strengthnumber of layers of mesh; nominal re

35、sistancemodular ratio of reinforcementmesh opening or sizespecific surface of reinforcementspecific surface of reinforcement in the longi-tudinal directionspecific surface of reinforcement in the trans-verse directionvolumevolumefractionfractionof reinforcementof reinforceme n t fo r meshlayer ivolu

36、me fraction of reinforcement in the longi-tudinal directionvolume fractionverse directionof reinforcement in th e trans-factor defining depth of rectangular stressblock (ACI 318, Section 10.2.7.3)global efficiency factor of embedded rein-forcement in resisting tension or tensile-bending loadsvalue o

37、f q when the load or stress is appliedalong the longitudinal direction of the meshsystem or rod reinforcementvalue of q when the load o r stress is Sappliedalong the transverse direction of the mesh re-inforcement system or rod reinforcementvalue of 7 when the load or stress is appliedalong a direct

38、ion forming an angle 0 with thelongitudinal directionultimate compressive strain of mortar (gener-ally assumed to be 0.003)strain of mesh reinforcement at laye r iJnominal yield strain of mesh reinforcement =VEtotal surface area of bonded reinforcementper unit lengthstress in ferrocement composite a

39、t yielding ofthe reinforcementstress i n ferrocement composit e a t ultimatestrengt h in tension2.3-DefinitionsThe following terms are defined because they do notappear in ACI 116R, Cement and Concrete Terminology,or have another meaning as applied to ferrocement.Armature -The total reinforcement sy

40、stem or skeletalreinforcement and mesh for a ferrocement boat.Longitudinal direction -Th e roll direction (longerdirection) of the mesh as produced in plant (see Fig.2 . 1) .Skeletal reinforcement - A planar framework of widelyspaced tied steel bars that provides shape and support forlayers of mesh

41、or fabric attached to either side.Fig. 2. l-Assumed longitudinal and transverse directions o f re in for cem entSpritzing -Spraying or squirting a mortar onto a sur-face.Transverse direction -Directio n of mesh normal to itslongitudinal direction ; also width direction of mesh asproduced in plant (s

42、ee Fig. 2.1).CHAPTER 3-MATERIALS REQUIREMENTS3.1-MatrixThe matrix used in ferrocement primarily consists ofmortar made with portland cement, water, and aggregate.A mineral admixture may be blended with the cement forspecial applications. Normally, the aggregate consists ofwell-graded fine aggregate

43、(sand) that passes a n ASTMNo. 8 (2.36 mm) sieve. If permitted by the size of themesh openings and the distance between layers o f mesh,small-size coarse aggregate may be added to the sand.The mortar matrix usually comprises more tha n 95percent of the ferrocement volume and has a great in-fluence o

44、n the behavior of the final product. Hence,great care should be exercised in choosing the constituentmaterials, namely cement, mineral admixtures, and fineaggregates, and in mixing and placing the mortar. Thechemical composition of the cement, the nature of theaggregate, the aggregate-cement ratio,

45、and the water-cement ratio are the major parameters governing theproperties of the mortar. The importance of these para-meters is discussed in detail i n ACI 549R and i n Refer-ences 1 through 4. The following sections give a briefsummary of the material requirements.3.1.1 Cement -The cement should

46、comply with ASTMC 150, ASTM C 595, or an equivalent standard. The ce-ment should be fresh, of uniform consistency, and free oflumps and foreign matter. It should be stored under dryconditions for as short a duration as possible.Detailed information regarding the types of cements,chemical and mineral

47、 admixtures, sampling , testing, andcorrosion can be found i n ACI 225R and in Referenc e 2.The most commonly used cement typ e is designated asType I i n ASTM C 150. Type II cement generates lessheat during hydration and is also moderately resistant tosulfates. Type III is a rapid-hardening cement

48、whichacquires early strength more rapidly than Type I cement.Type IV is a low-heat cement used for mass concrete andis seldom considered for ferrocement. Typ e V is a sul-fate-resisting cement used in structures exposed to sul-fate.The choice of a particular cement should depend onthe service condit

49、ions. Service conditions can be classifiedas electrochemically passive or active. Land-based struc-tures such as ferrocement silos, bins, and water tanks canbe considered as passive structures, except when in con-tact with sulfate-bearing soils, in which case the use ofsulfate-resistant cement, such as ASTM Type II or TypeV, may be necessary.For structures in electrochemically active environmentssuch as boats and barges, it may be necessary to specifysulfate-resistant cement because of the sulfates present insea water . ACI 357R reports that Type II cement wasfound adequate for sulfate resis