ACI 506.1R-2008 Guide to Fiber-Reinforced Shotcrete《纤维-钢筋喷浆混凝土指南》.pdf

1、ACI 506.1R-08Reported by ACI Committee 506Guide to Fiber-Reinforced ShotcreteGuide to Fiber-Reinforced ShotcreteFirst PrintingNovember 2008ISBN 978-0-87031-312-7American Concrete InstituteAdvancing concrete knowledgeCopyright by the American Concrete Institute, Farmington Hills, MI. All rights reser

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10、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 506.1R-08 supersedes ACI 506.1R-98 and was adopted and publishedNovember 2008.Copyright 2008, Americ

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12、e or retrieval system or device, unless permission in writingis obtained from the copyright proprietors.506.1R-1ACI Committee Reports, Guides, Manuals, StandardPractices, and Commentaries are intended for guidance inplanning, designing, executing, and inspecting construction.This document is intende

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14、. 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 mandatory language for

15、incorporation bythe Architect/Engineer.Guide to Fiber-Reinforced ShotcreteReported by ACI Committee 506ACI 506.1R-08This guide describes the technology and applications of fiber-reinforcedshotcrete (FRS) using synthetic and steel fibers. Mechanical properties,particularly toughness, impact, and flex

16、ural strength, are improved by fiberaddition, and these improvements are described along with other typicalproperties and benefits, such as control of shrinkage cracking. Proportionsof typical mixtures, batching, mixing, and application procedures aredescribed, including methods of reducing rebound

17、and equipment used toapply FRS. Applications of FRS are described, including rock-slope stabili-zation work, construction and repair of tunnel and mining linings, fireexplosive spalling-resistant linings, channel linings, pools and rockscapes,and structure repair. Available design information is bri

18、efly discussed, anddesign references are listed.Keywords: fiber-reinforced shotcrete; fibers; linings; mining; repair; steelfibers; synthetic fibers; tunnels.CONTENTSChapter 1Introduction and scope, p. 506.1R-21.1Introduction1.2Scope1.3Historical backgroundChapter 2Notation and definitions, p. 506.1

19、R-22.1Notation2.2DefinitionsChapter 3Materials, p. 506.1R-23.1General3.2Fibers3.3Other materialsChapter 4Mixture proportions, p. 506.1R-34.1General4.2Wet-process4.3Dry-processJon B. Ardahl Jill E. Glassgold Jeffery L. Novak*Raymond C. Schallom, III*Lars F. Balck, Jr. Charles S. Hanskat H. Celik Ozyi

20、ldirim Raymond J. SchutzMichael Ballou*Warren L. Harrison Harvey W. Parker Philip T. SeabrookNemkumar Banthia*Thomas Hennings*Ryan E. Poole W. L. Snow, Sr.Chris D. Breeds Merlyn Isaak John H. Pye Curtis WhitePatrick O. Bridger Marc Jolin James A. Ragland*Peter T. YenWern-Ping “Nick” Chen Kristian Lo

21、evlie Venkataswamy Ramakrisnan George Yoggy*Jean-Franois Dufour*Mark R. Lukkarila Michael Rispin Christopher M. ZyndaJohn R. Fichter Gregory McKinnon*Subcommittee members who prepared this report.Subcommittee Chair.Peter C. TatnallChairLawrence J. TottenVice ChairDudley R. Morgan*Secretary506.1R-2 A

22、CI COMMITTEE REPORTChapter 5Production, p. 506.1R-45.1General5.2Batching and mixing5.3ApplicationChapter 6Test procedures, p. 506.1R-46.1General6.2Fresh properties6.3Hardened propertiesChapter 7Performance of fiber-reinforced shotcrete, p. 506.1R-67.1Flexural strength7.2Compressive strength7.3Shear

23、strength7.4Bond strength7.5Rebound considerations7.6Shrinkage crack control7.7Impact resistance7.8Thermal explosive spallingChapter 8Design considerations, p. 506.1R-88.1General8.2Empirical design8.3Comparable moment capacityChapter 9Specification and quality control considerations, p. 506.1R-99.1Ge

24、neral9.2Performance specifications9.3Prescriptive specificationsChapter 10Applications, p. 506.1R-910.1General10.2Ground support10.3Rehabilitation and repair10.4Architectural shotcrete10.5Explosive spalling resistanceChapter 11References, p. 506.1R-1111.1Referenced standards and reports11.2Cited ref

25、erencesAppendixExample of comparable moment capacity calculations, p. 506.1R-13CHAPTER 1INTRODUCTION AND SCOPE1.1IntroductionFiber-reinforced shotcrete (FRS) is mortar or concretecontaining discontinuous discrete fibers that is pneumaticallyprojected at high velocity onto a surface. Continuousmeshes

26、, woven fabrics, and long rods are not considered asdiscrete fiber-type reinforcing elements in this guide.1.2ScopeThis document provides information on fiber-reinforcedshotcrete using synthetic and steel fibers. Topics coveredinclude materials used, mixture proportions, production ofshotcrete, test

27、ing procedures, performance of FRS, designconsiderations (including an example in the Appendix),specifications, and some examples of applications.1.3Historical backgroundFRS with steel fibers was first placed in North Americaearly in 1971 in experimental work directed by Lankard, etal. (1971). Steel

28、 FRS (SFRS) was proposed for undergroundsupport by Parker in 1971 (Parker 1974). Additional trialswere made by Poad in an investigation of new and improvedmethods of using shotcrete for underground support (Poad etal. 1975). Subsequently, the first practical applications ofSFRS were made in a tunnel

29、 adit at Ririe Dam, ID in 1973(Kaden 1977). Since that time, SFRS has been usedthroughout the world. Shotcrete using micropolypropylenefibers was first placed in Europe in 1968 (Hannant 1978).Macrosynthetic fibers for use in shotcrete were developed inthe mid-1990s and have been used in mining and s

30、lope stabi-lization projects (Morgan and Heere 2000).CHAPTER 2NOTATION AND DEFINITIONS2.1NotationAS= area of conventional steel per unit widtha = ASfY/0.85fc bb = unit width of sectiond = moment arm from loaded surface to center ofreinforcement= post-cracking residual flexural strength of a 4 in.(10

31、0 mm) deep beam as determined at 0.02 in.(0.5 mm) deflection (Span/600) using ASTMC1609/C1609MfY= yield strength of conventional reinforcementfc = compressive strength of shotcretet = FRS section thickness = strength reduction factor, = 0.9 for flexure2.2Definitionsaspect ratio, fiberthe ratio of le

32、ngth to diameter of afiber in which the diameter may be an equivalent diameter.deniermeasure of fiber diameter, taken as the mass ingrams of 9000 m (29,528 ft) of the fiber.equivalent diameter, fiberdiameter of a circle with anarea equal to the cross-sectional area of the fiber.macrofibera fiber wit

33、h an equivalent diameter greaterthan or equal to 0.012 in. (0.3 mm) for use in concrete.microfibera fiber with an equivalent diameter less than0.012 in. (0.3 mm) for use in concrete.CHAPTER 3MATERIALS3.1GeneralFRS is conventional shotcrete with fibers added. Materialsfor use in FRS should conform to

34、 the requirements of ASTMC1436, which covers the typical materials used in shotcrete,including chemical and mineral admixtures, fibers, and thecombined grading of aggregates for fine and coarse mixtures:Grading No. 1: No. 4 to No. 100 sieve (4.75 mm to 150 m),and No. 2: 3/8 in. to No. 100 sieve (9.5

35、 mm to 150 m).f600100GUIDE TO FIBER-REINFORCED SHOTCRETE 506.1R-33.2FibersFibers for use in shotcrete can be made of steel, glass,synthetic polymers, and natural materials. Only steel andsynthetic fibers are considered herein because they are themost commonly used. Figures 3.1 and 3.2 illustrate ste

36、el andmacrosynthetic fibers being used in shotcrete.Fibers for use in shotcrete are generally divided into twogroups by their diameter. Fibers with equivalent diametersgreater than 0.012 in. (0.3 mm) are known as macrofibers;fibers with diameters less than 0.012 in. (0.3 mm) are knownas microfibers.

37、 The descriptor denier is often used to indicatethe fineness of microfibers. A typical synthetic shotcretemicrofiber has a denier of 6, which results in an equivalentdiameter of 0.0012 in. (32 m). More information on fibers,denier, and equivalent diameters can be found in ACI 544.1R.One parameter to

38、 characterize macrofibers is the aspectratio. Typical aspect ratios of macrofibers for shotcrete rangefrom 40 to 65 for common fiber lengths of 0.75 to 2 in. (19to 50 mm), although steel fiber lengths are generally lessthan 1.5 in. (38 mm). Synthetic microfiber lengths vary from0.25 to 2 in. (6 to 5

39、0 mm).ASTM C1116/C1116M defines the required properties ofFRS and fibers used in shotcrete.3.2.1 MacrofibersMacrofibers are defined as thosefibers for use in shotcrete with equivalent diameters greaterthan 0.012 in. (0.3 mm). The majority of macrofibers used inshotcrete are either steel or synthetic

40、 fibers. Steel fibers usedin shotcrete are generally between 0.75 to 1.4 in. (19 to 35 mm)in length and 0.016 to 0.03 in. (0.4 to 0.8 mm) in equivalentdiameter. Synthetic macrofibers can be longer and varybetween 1.5 to 2 in. (40 to 50 mm) long, with equivalentdiameters similar to the steel fibers.

41、The fibers should meetthe requirements of ASTM C1436.3.2.2 MicrofibersMicrofibers used in shotcrete arenormally polyolefin-based or nylon, and should meet therequirements of ASTM C1436. If the microfibers are used toresist explosive spalling in fires, then fibers should bepolypropylene, with equival

42、ent diameters less than 0.0013 in.(33 m) and less than 0.5 in. (12 mm) long (Tatnall 2002).3.3Other materialsWhile the normal materials used in shotcrete are used inFRS, supplementary cementitious materials are often used,such as silica fume, slag, and fly ash. For applications thatrequire vertical

43、and overhead placement with macrofibers,these materials can help build thicker layers withoutsloughing and reduce fiber rebound. For shotcretes thatcontain more than about 0.3% by volume of fibers, the additionof water-reducing admixtures is common to maintain desiredwater-cementitious material rati

44、os. Admixtures that meet therequirements of ASTM C1436 are normally acceptable foruse in FRS.CHAPTER 4MIXTURE PROPORTIONS4.1GeneralProportioning shotcrete mixtures that contain fibersshould follow the general guidelines outlined in ACI 506R.While FRS mixtures are normally proportioned to attain aspe

45、cified compressive strength, many times an ultimate flexuralstrength and postcrack performance, such as residualstrength(s), or an energy absorption, toughness, or both, arespecified. Nonfibrous shotcrete proportioning methodsshould be used to attain compressive and flexural require-ments (ACI 506R)

46、, and the recommendations from fibersuppliers selected for the type (material and shape) andquantity of fibers to attain postcrack performance require-ments should be used.4.2Wet processFRS for wet-process shotcrete is typically delivered to thepump in accordance with ASTM C1116/C1116M. Becauserebou

47、nd of macrofibers is typically less in wet-process shotcrete,fiber dosages are sometimes less than for dry-process shotcretefor the same postcrack performance. Steel fiber quantities usedare in the range of 20 to 100 lb/yd3(12 to 60 kg/m3).Macrosynthetic fiber quantities are usually in the range of8

48、.5 to 15 lb/yd3(5 to 9 kg/m3). Microsynthetic fibers arenormally used at dosages of 1 to 4 lb/yd3(0.6 to 2.4 kg/m3).4.3Dry processDry-process shotcrete can be delivered to the shotcretemachine in transit mix trucks, volumetric batcher, inFig. 3.1Examples of steel fibers.Fig. 3.2Examples of macrosynt

49、hetic fibers.506.1R-4 ACI COMMITTEE REPORTprepared prepackaged containers, or mixed on site. Becauserebound of fibers in dry-process is normally greater thanrebound of fibers for wet-process shotcrete, fiber quantitiesmay be slightly higher than those indicated in Section 4.2(Dufour et al. 2006). Therefore some macrosynthetic fibersdo not lend themselves to successful shooting using the dry-process because they do not get coated with the cementitiouspaste and can tend to fly away in the shotcrete stream. Use