ACI 549R-1997 Report on Ferrocement《钢丝网水泥报告》.pdf

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1、ACI 549R-97 became effective January 24, 1997. This document replaces ACI549R-93.Copyright 1997, 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 dev

2、ice, printed, written, or oral, or 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, Manuals, StandardPractices, and Commentaries are intended fo

3、r guidance inplanning, designing, executing, and inspecting construction.This document 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 conta

4、ins.The American Concrete Institute disclaims any and allresponsibility for 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/

5、Engineer to be a part of the contract documents, theyshall be restated in mandatory language for incorporation bythe Architect/Engineer.1The report and ACI publication SP-61, FerrocementMaterials and Appli-cations, provide technical information on the mechanical properties,performance, and applicati

6、ons of ferrocement. The intent of this report is topromote the more effective use of ferrocement as a construction materialfor terrestrial structures in contrast to marine structures, where it has beenso far most widely used.Keywords: composite materials; compressive strength; constructionmaterials;

7、 crack width and spacing; fatigue (materials); ferrocement;fibers; flexural strength; impact; mechanical properties; reinforced concrete;tension; welded wire fabric.CONTENTSChapter 1Introduction, p. 21.1Definition of ferrocement1.2Ferrocement trendsChapter 2History, p. 2Chapter 3Composition and cons

8、truction, p. 53.1Introduction3.2Matrix3.3Reinforcement3.4Admixtures3.5Matrix mix proportions3.6Coatings3.7Fabrication proceduresChapter 4Physical and mechanical properties,p. 84.1Introduction4.2Ultimate strength under static load4.3First crack strength under static load4.4Elasticity and load-deforma

9、tion behavior 4.5Strength under fatigue loading4.6Impact resistance4.7Crack development and leakage4.8Shrinkage and creep4.9Durability4.10Fire resistanceChapter 5Performance criteria, p. 165.1Introduction5.2Design methods5.3Definitions5.4Allowable tensile stress5.5Allowable compressive stress5.6Volu

10、me fraction and specific surface of reinforcement 5.7Cover requirements5.8Crack width limitations5.9Stress range5.10DurabilityChapter 6Applications of ferrocement, p. 186.1Introduction6.2Boats6.3Silos 6.4Tanks 6.5Roofs6.6Miscellaneous applications6.7SummaryReport on FerrocementReported by ACI Commit

11、tee 549ACI 549R-97(Reapproved 2009)P. N. Balaguru*ChairmanParviz SoroushianSecretaryShuaib H. Ahmad David M. Gale Barzin Mobasher D. V. Reddy Methi WecharatanaM. Arockiasamy Antonio J. Guerra John L. Mulder James P. Romauldi Robert B. WilliamsonNemkumar Banthia Lloyd Hackman Antoine E. Naaman Surend

12、ra P. Shah Robert C. ZellersGordon B. Batson Martin E. Iorns Antonio Nanni Narayan Swamy Ronald F. ZolloJose O. Castro Colin D. JohnstonP. Paramasivam*Ben L. Tilsen Rogerio C. ZubietaJames I. Daniel Mohammad Mansur*Members responsible for the revisionChairman of the subcommittee on ferrocement2 REPO

13、RT ON FERROCEMENT (ACI 549R-97)American Concrete Institute Copyrighted Materialwww.concrete.orgChapter 7Research needs, p. 227.1Introduction 7.2Scope of research needs7.3Specific research needs7.4SummaryChapter 8References, p. 238.1Specific and/or recommended references8.2Cited referencesCHAPTER 1IN

14、TRODUCTION1.1Definition of ferrocementFerrocement is a form of reinforced concrete that differsfrom conventional reinforced or prestressed concreteprimarily by the manner in which the reinforcing elements aredispersed and arranged. It consists of closely spaced, multiplelayers of mesh or fine rods c

15、ompletely embedded in cementmortar. A composite material is formed that behaves differ-ently from conventional reinforced concrete in strength, defor-mation, and potential applications, and thus is classified as aseparate and distinct material. It can be formed into thin panelsor sections, mostly le

16、ss than 1 in. (25 mm) thick, with only athin mortar cover over the outermost layers of reinforcement.Unlike conventional concrete, ferrocement reinforcement canbe assembled into its final desired shape and the mortar can beplastered directly in place without the use of a form.The term ferrocement im

17、plies the combination of a ferrousreinforcement embedded in a cementitious matrix. Yet thereare characteristics of ferrocement that can be achieved withreinforcement other than steel meshes or rods. For instance,the ancient and universal method of building huts by usingreeds to reinforce dried mud (

18、wattle and daub) could beconsidered a forerunner of ferrocement. The use of non-metallic mesh is being explored at several universities. Suchmeshes include woven alkali resistant glass, organic wovenfabrics such as polypropylene, and organic natural fabricsmade with jute, burlap, or bamboo fibers. T

19、herefore, theterm ferrocement currently implies the use of other than steelmaterial as reinforcement. The following definition wasadopted by the Committee: “Ferrocement is a type of thinwall reinforced concrete commonly constructed of hydrauliccement mortar reinforced with closely spaced layers ofco

20、ntinuous and relatively small size wire mesh. The meshmay be made of metallic or other suitable materials.”The preceding definition is relatively broad in scope. Itimplies that, although ferrocement is a form of reinforcedconcrete, it is a composite material. Hence the basic conceptsunderlying the b

21、ehavior and mechanics of composite mate-rials should be applicable to ferrocement.1.2Ferrocement trendsWidespread use of ferrocement in the construction industryhas occurred during the last 25 years, but the usage of thisnew construction material in the U.S. is still in its infancy.The main worldwid

22、e applications of ferrocement construc-tion to date have been for silos, tanks, roofs, and mostly boats.The construction of ferrocement can be divided into fourphases:1. fabricating the steel rods to form a skeletal framing system;2. tying or fastening rods and mesh to the skeletal framing;3. plaste

23、ring; and4. curing.Note that relatively low level technical skills are requiredfor Phases 1 and 3, while Phase 2 is very labor-intensive.This is a shortcoming for industrially developed countriesbut an advantage for countries where unskilled labor is rela-tively abundant. In developed countries wher

24、e labor is rela-tively expensive, shotcreting (as shown in Fig. 1.1),mechanized fabrication of reinforcement cages,1or lami-nating techniques similar to those developed for marinestructures can reduce the labor cost.2,3Experience has shownthat the quality of mortar and its application to the mesh ar

25、ethe most critical phases. Mortar can be applied by hand or byshotcreting. Since formwork is usually not required, incontrast to conventionally reinforced concrete construction,ferrocement is especially suitable for structures with curvedsurfaces, such as shells and free-form shapes. In someinstance

26、s, its use as a permanent form for a reinforcedconcrete structure can be economically justified.4Ferrocement has a very high tensile strength-to-weightratio and superior cracking behavior in comparison toconventional reinforced concrete. This means that thin ferroce-ment structures can be made relat

27、ively light and watertight.Hence, ferrocement is an attractive material for the constructionof boats, barges, prefabricated housing units, and other portablestructures. However, even though for these applications ferroce-ment is more efficient on a weight basis, it is frequently moreeconomical to bu

28、ild with conventionally reinforced concrete.This is especially true in developed countries where, due tohigher material cost and the labor-intensive nature of ferroce-ment, its use is limited to specialized applications such asdomes, wind tunnels, roof shells, mobile homes, modularhousing parts (Fig

29、. 1.2), tanks, and swimming pools.While construction with ferrocement may not be cost-effective in many applications, this material competes favor-ably with fiberglass laminates or steel used in special struc-tures. Two feasibility studies have shown ferrocement coststo be less than those of steel o

30、r fiberglass in the constructionof wind tunnels5or hot water storage tanks.6It is believedthat the development of new mesh reinforcing systems andmore efficient production techniques will make ferrocementcompetitive in a wide range of applications requiring thinstructural elements.CHAPTER 2HISTORYTh

31、e known use of lime, gypsum, and natural cement mortargoes back as far as 3000 B.C.7,8Early applications were gener-ally limited to joining stone blocks, plastering, or coating. Itwas not until the time of the Romans, however, that naturalcement mortar was widely used as a structural material.In all

32、 early developments, concrete was viewed as a materialthat could be used effectively only in compression. Althoughthe concept of embedding steel or iron rods within freshconcrete in the direction of anticipated tension is associatedwith the latter half of the 19th century, the construction of aREPOR

33、T ON FERROCEMENT (ACI 549R-97) 3American Concrete Institute Copyrighted Materialwww.concrete.orgFig. 1.1Mortar being applied to wire mesh by shotcreting to form a shell (Naaman).4 REPORT ON FERROCEMENT (ACI 549R-97)American Concrete Institute Copyrighted Materialwww.concrete.orggreat gateway to the

34、Acropolis (437 B.C.) required widerspans than were the custom for Greek builders; Mnesiclesused iron rods cemented within grooves cut into the tensionside of the marble beams. In the 18th century a Frenchman,Soufflot, attempted to increase the strength of masonryconstruction by burying iron rods in

35、the mortar between thejoints. This attempt had limited success because the iron rodsrusted and expansive pressures caused by the products ofcorrosion ruptured the joints.The concept of embedding reinforcement into wetconcrete to form what we now recognize as reinforcedconcrete almost simultaneously

36、to three persons. JosephMonier (1823-1906), a French gardener, incorporated amesh of iron rods into large planting pots in 1849. AnEnglishman, Wilkinson, made reinforced concrete beams forbuildings by putting old mining ropes in the tension side ofthe beams.9And finally, J. L. Lambot made a concrete

37、rowing boat in which the reinforcement was in the form of anetwork (or basket) of wires and interlaced thin rods.10,11Inthe U.S., during about the same period, Thaddeus Hyatt(1816-1901) undertook extensive tests on reinforcedconcrete slabs and beams and greatly contributed to rational-izing reinforc

38、ed concrete theory.12It is, however, the early work of Lambot that is of mostinterest to us, not only because it was one of the first applica-tions of reinforced concrete, but also because it was a form offerrocement. His patent on wire-reinforced boats that wasissued in 1847 (translated from French

39、 in Ref. 13) stated:“My invention shows a new product which helps toreplace timber where it is endangered by wetness, as in woodflooring, water containers, plant pots, etc. The new substanceconsists of a metal net of wire or sticks which are connectedor formed like a flexible woven mat. I give this

40、net a formwhich looks in the best possible way, similar to the articles,I want to create. Then I put in hydraulic cement or similarbitumen tar or mix, to fill up the joints.”This was the birth of reinforced concrete, but subsequentdevelopment differed from Lambots concept. The tech-nology of the per

41、iod could not accommodate the time andeffort needed to make mesh of thousands of wires. Instead,large rods were used to make what is now called conven-tional reinforced concrete, and the concept of ferrocementwas almost forgotten for 100 years.Reinforced concrete for boat building reappeared briefly

42、during the First World War, when a shortage of steel platesforced a search for other boat-building materials.14However,the conventional use of large-diameter steel rods to reinforcethe concrete required thick hulls, making the vessels lesspractical to operate than lighter wood or steel ships.In the

43、early 1940s, Pier Luigi Nervi resurrected the originalferrocement concept when he observed that reinforcingconcrete with layers of wire mesh produced a materialFig. 1.2Prefabrication of housing modules.REPORT ON FERROCEMENT (ACI 549R-97) 5American Concrete Institute Copyrighted Materialwww.concrete.

44、orgpossessing the mechanical characteristics of an approxi-mately homogeneous material and capable of resistingimpact.15,16Thin slabs of concrete reinforced in this mannerproved to be flexible, elastic, and exceptionally strong. Afterthe Second World War, Nervi demonstrated the utility offerrocement

45、 as a boat-building material. His firm built the165-ton motor sailer Irene with a ferrocement hull 1.4 in.(36 mm) thick.15Ferrocement gained wide acceptance in the early 1960s inthe United Kingdom, New Zealand, and Australia. In 1965,an American-owned ferrocement yacht built in NewZealand, the 53 ft

46、 (16 m) Awahnee, circumnavigated theworld twice without serious problems, although it encoun-tered several mishaps.13Emphasis on ferrocement as a boat-building materialduring the 1960s has obscured Nervis noteworthy applica-tions to buildings. He built a small storehouse of ferroce-ment in 1947. Lat

47、er he covered the swimming pool at theItalian Naval Academy with a 50 ft (15 m) diameter domeand then the famous Turin Exhibition Halla roof systemspanning 300 ft (91 m).16In both cases, ferrocement servedas permanent forms for the structural system, including themain support ribs.In spite of the ra

48、ther unique properties of ferrocement,and the interest created by Nervis work, use of the materialdid not expand much beyond its application to boatconstruction. However, the universal availability of thebasic ingredients of ferrocement, steel mesh, and concretecreated interest in the potential appl

49、ication of this materialin developing countries for everything from roofs to wallsof low cost housing to food storage bins and irrigationtroughs. In 1972, the National Academy of Sciences,through its Board on Science and Technology for Interna-tional Development, established the Ad Hoc Panel on theUtilization of Ferrocement in Developing Countries. Thereport of the Panel greatly stimulated interest in thenonmarine applications of this versatile material.17-19During the late 1960s and early 1970s, the interest of thescientifi