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1、ACI 506.1R-08 Reported by ACI Committee 506 Guide to Fiber-Reinforced Shotcrete Guide to Fiber-Reinforced Shotcrete First Printing November 2008 ISBN 978-0-87031-312-7 American Concrete Institute Advancing concrete knowledge Copyright by the American Concrete Institute, Farmington Hills, MI. All rig
2、hts reserved. This material may not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of ACI. The technical committees responsible for ACI committee reports and standards strive to avoid ambig
3、uities, omissions, and errors in these documents. In spite of these efforts, the users of ACI documents occasionally find information or requirements that may be subject to more than one interpretation or may be incomplete or incorrect. Users who have suggestions for the improvement of ACI documents
4、 are requested to contact ACI. Proper use of this document includes periodically checking for errata at www.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 significance and limitat
5、ions of its content and recommendations and who will accept responsibility for the application of the material it contains. Individuals who use this publication in any way assume all risk and accept total responsibility for the application and use of this information. All information in this publica
6、tion 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 or non-infringement. ACI and its members disclaim liability for damages of any kind, including any special, indi
7、rect, incidental, or consequential damages, including without limitation, lost revenues or lost profits, which may result from the use of this publication. It is the responsibility of the user of this document to establish health and safety practices appropriate to the specific circumstances involve
8、d with its use. ACI does not make any representations with regard to health and safety issues and the use of this document. The user must determine the applicability of all regulatory limitations before applying the document and must comply with all applicable laws and regulations, including but not
9、 limited to, United States Occupational Safety and Health Administration (OSHA) health and safety standards. Order information: ACI documents are available in print, by download, on CD-ROM, through electronic subscription, or reprint and may be obtained by contacting ACI. Most ACI standards and comm
10、ittee reports are gathered together in the annually revised ACI Manual of Concrete Practice (MCP). American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331 U.S.A. Phone:248-848-3700 Fax:248-848-3701 www.concrete.org ACI 506.1R-08 supersedes ACI 506.1R-98 and was adopted and pu
11、blished November 2008. Copyright 2008, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound
12、or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors. 506.1R-1 ACI Committee Reports, Guides, Manuals, Standard Practices, and Commentaries are intended for guidance in planning, designing, executing
13、, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept responsibility for the application of the material it contains. The American Concrete Institute di
14、sclaims any and all responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom. Reference to this document shall not be made in contract documents. If items found in this document are desired by the Architect/Engineer to be a part of the cont
15、ract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer. Guide to Fiber-Reinforced Shotcrete Reported by ACI Committee 506 ACI 506.1R-08 This guide describes the technology and applications of fiber-reinforced shotcrete (FRS) using synthetic and steel
16、 fibers. Mechanical properties, particularly toughness, impact, and flexural strength, are improved by fiber addition, and these improvements are described along with other typical properties and benefits, such as control of shrinkage cracking. Proportions of typical mixtures, batching, mixing, and
17、application procedures are described, including methods of reducing rebound and equipment used to apply FRS. Applications of FRS are described, including rock-slope stabili- zation work, construction and repair of tunnel and mining linings, fire explosive spalling-resistant linings, channel linings,
18、 pools and rockscapes, and structure repair. Available design information is briefly discussed, and design references are listed. Keywords: fiber-reinforced shotcrete; fibers; linings; mining; repair; steel fibers; synthetic fibers; tunnels. CONTENTS Chapter 1Introduction and scope, p. 506.1R-2 1.1I
19、ntroduction 1.2Scope 1.3Historical background Chapter 2Notation and definitions, p. 506.1R-2 2.1Notation 2.2Definitions Chapter 3Materials, p. 506.1R-2 3.1General 3.2Fibers 3.3Other materials Chapter 4Mixture proportions, p. 506.1R-3 4.1General 4.2Wet-process 4.3Dry-process Jon B. ArdahlJill E. Glas
20、sgoldJeffery L. Novak*Raymond C. Schallom, III* Lars F. Balck, Jr.Charles S. HanskatH. Celik OzyildirimRaymond J. Schutz Michael Ballou*Warren L. HarrisonHarvey W. ParkerPhilip T. Seabrook Nemkumar Banthia*Thomas Hennings*Ryan E. PooleW. L. Snow, Sr. Chris D. BreedsMerlyn IsaakJohn H. PyeCurtis Whit
21、e Patrick O. BridgerMarc JolinJames A. Ragland*Peter T. Yen Wern-Ping “Nick” ChenKristian LoevlieVenkataswamy RamakrisnanGeorge Yoggy* Jean-Franois Dufour*Mark R. LukkarilaMichael RispinChristopher M. Zynda John R. FichterGregory McKinnon *Subcommittee members who prepared this report. Subcommittee
22、Chair. Peter C. Tatnall Chair Lawrence J. Totten Vice Chair Dudley R. Morgan* Secretary 506.1R-2ACI COMMITTEE REPORT Chapter 5Production, p. 506.1R-4 5.1General 5.2Batching and mixing 5.3Application Chapter 6Test procedures, p. 506.1R-4 6.1General 6.2Fresh properties 6.3Hardened properties Chapter 7
23、Performance of fiber-reinforced shotcrete, p. 506.1R-6 7.1Flexural strength 7.2Compressive strength 7.3Shear strength 7.4Bond strength 7.5Rebound considerations 7.6Shrinkage crack control 7.7Impact resistance 7.8Thermal explosive spalling Chapter 8Design considerations, p. 506.1R-8 8.1General 8.2Emp
24、irical design 8.3Comparable moment capacity Chapter 9Specification and quality control considerations, p. 506.1R-9 9.1General 9.2Performance specifications 9.3Prescriptive specifications Chapter 10Applications, p. 506.1R-9 10.1General 10.2Ground support 10.3Rehabilitation and repair 10.4Architectura
25、l shotcrete 10.5Explosive spalling resistance Chapter 11References, p. 506.1R-11 11.1Referenced standards and reports 11.2Cited references AppendixExample of comparable moment capacity calculations, p. 506.1R-13 CHAPTER 1INTRODUCTION AND SCOPE 1.1Introduction Fiber-reinforced shotcrete (FRS) is mort
26、ar or concrete containing discontinuous discrete fibers that is pneumatically projected at high velocity onto a surface. Continuous meshes, woven fabrics, and long rods are not considered as discrete fiber-type reinforcing elements in this guide. 1.2Scope This document provides information on fiber-
27、reinforced shotcrete using synthetic and steel fibers. Topics covered include materials used, mixture proportions, production of shotcrete, testing procedures, performance of FRS, design considerations (including an example in the Appendix), specifications, and some examples of applications. 1.3Hist
28、orical background FRS with steel fibers was first placed in North America early in 1971 in experimental work directed by Lankard, et al. (1971). Steel FRS (SFRS) was proposed for underground support by Parker in 1971 (Parker 1974). Additional trials were made by Poad in an investigation of new and i
29、mproved methods of using shotcrete for underground support (Poad et al. 1975). Subsequently, the first practical applications of SFRS were made in a tunnel adit at Ririe Dam, ID in 1973 (Kaden 1977). Since that time, SFRS has been used throughout the world. Shotcrete using micropolypropylene fibers
30、was first placed in Europe in 1968 (Hannant 1978). Macrosynthetic fibers for use in shotcrete were developed in the mid-1990s and have been used in mining and slope stabi- lization projects (Morgan and Heere 2000). CHAPTER 2NOTATION AND DEFINITIONS 2.1Notation AS= area of conventional steel per unit
31、 width a=ASfY/0.85fcb b=unit width of section d=moment arm from loaded surface to center of reinforcement =post-cracking residual flexural strength of a 4 in. (100 mm) deep beam as determined at 0.02 in. (0.5 mm) deflection (Span/600) using ASTM C1609/C1609M fY=yield strength of conventional reinfor
32、cement fc=compressive strength of shotcrete t=FRS section thickness =strength reduction factor, = 0.9 for flexure 2.2Definitions aspect ratio, fiberthe ratio of length to diameter of a fiber in which the diameter may be an equivalent diameter. deniermeasure of fiber diameter, taken as the mass in gr
33、ams of 9000 m (29,528 ft) of the fiber. equivalent diameter, fiberdiameter of a circle with an area equal to the cross-sectional area of the fiber. macrofibera fiber with an equivalent diameter greater than or equal to 0.012 in. (0.3 mm) for use in concrete. microfibera fiber with an equivalent diam
34、eter less than 0.012 in. (0.3 mm) for use in concrete. CHAPTER 3MATERIALS 3.1General FRS is conventional shotcrete with fibers added. Materials for use in FRS should conform to the requirements of ASTM C1436, which covers the typical materials used in shotcrete, including chemical and mineral admixt
35、ures, fibers, and the combined 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 mm to 150 m). f600 100 GUIDE TO FIBER-REINFORCED SHOTCRETE506.1R-3 3.2Fibers Fibers for use in shotcrete can be made o
36、f steel, glass, synthetic polymers, and natural materials. Only steel and synthetic fibers are considered herein because they are the most commonly used. Figures 3.1 and 3.2 illustrate steel and macrosynthetic fibers being used in shotcrete. Fibers for use in shotcrete are generally divided into two
37、 groups by their diameter. Fibers with equivalent diameters greater than 0.012 in. (0.3 mm) are known as macrofibers; fibers with diameters less than 0.012 in. (0.3 mm) are known as microfibers. The descriptor denier is often used to indicate the fineness of microfibers. A typical synthetic shotcret
38、e microfiber has a denier of 6, which results in an equivalent diameter of 0.0012 in. (32 m). More information on fibers, denier, and equivalent diameters can be found in ACI 544.1R. One parameter to characterize macrofibers is the aspect ratio. Typical aspect ratios of macrofibers for shotcrete ran
39、ge from 40 to 65 for common fiber lengths of 0.75 to 2 in. (19 to 50 mm), although steel fiber lengths are generally less than 1.5 in. (38 mm). Synthetic microfiber lengths vary from 0.25 to 2 in. (6 to 50 mm). ASTM C1116/C1116M defines the required properties of FRS and fibers used in shotcrete. 3.
40、2.1 MacrofibersMacrofibers are defined as those fibers for use in shotcrete with equivalent diameters greater than 0.012 in. (0.3 mm). The majority of macrofibers used in shotcrete are either steel or synthetic fibers. Steel fibers used in shotcrete are generally between 0.75 to 1.4 in. (19 to 35 mm
41、) in length and 0.016 to 0.03 in. (0.4 to 0.8 mm) in equivalent diameter. Synthetic macrofibers can be longer and vary between 1.5 to 2 in. (40 to 50 mm) long, with equivalent diameters similar to the steel fibers. The fibers should meet the requirements of ASTM C1436. 3.2.2 MicrofibersMicrofibers u
42、sed in shotcrete are normally polyolefin-based or nylon, and should meet the requirements of ASTM C1436. If the microfibers are used to resist explosive spalling in fires, then fibers should be polypropylene, with equivalent diameters less than 0.0013 in. (33 m) and less than 0.5 in. (12 mm) long (T
43、atnall 2002). 3.3Other materials While the normal materials used in shotcrete are used in FRS, supplementary cementitious materials are often used, such as silica fume, slag, and fly ash. For applications that require vertical and overhead placement with macrofibers, these materials can help build t
44、hicker layers without sloughing and reduce fiber rebound. For shotcretes that contain more than about 0.3% by volume of fibers, the addition of water-reducing admixtures is common to maintain desired water-cementitious material ratios. Admixtures that meet the requirements of ASTM C1436 are normally
45、 acceptable for use in FRS. CHAPTER 4MIXTURE PROPORTIONS 4.1General Proportioning shotcrete mixtures that contain fibers should follow the general guidelines outlined in ACI 506R. While FRS mixtures are normally proportioned to attain a specified compressive strength, many times an ultimate flexural
46、 strength and postcrack performance, such as residual strength(s), or an energy absorption, toughness, or both, are specified. Nonfibrous shotcrete proportioning methods should be used to attain compressive and flexural require- ments (ACI 506R), and the recommendations from fiber suppliers selected
47、 for the type (material and shape) and quantity of fibers to attain postcrack performance require- ments should be used. 4.2Wet process FRS for wet-process shotcrete is typically delivered to the pump in accordance with ASTM C1116/C1116M. Because rebound of macrofibers is typically less in wet-proce
48、ss shotcrete, fiber dosages are sometimes less than for dry-process shotcrete for the same postcrack performance. Steel fiber quantities used are in the range of 20 to 100 lb/yd3 (12 to 60 kg/m3). Macrosynthetic fiber quantities are usually in the range of 8.5 to 15 lb/yd3 (5 to 9 kg/m3). Microsynth
49、etic fibers are normally used at dosages of 1 to 4 lb/yd3 (0.6 to 2.4 kg/m3). 4.3Dry process Dry-process shotcrete can be delivered to the shotcrete machine in transit mix trucks, volumetric batcher, in Fig. 3.1Examples of steel fibers. Fig. 3.2Examples of macrosynthetic fibers. 506.1R-4ACI COMMITTEE REPORT prepared prepackaged containers, or mixed on site. Because rebound of fibers in dry-process is normally greater than rebound of fibers for wet-process shotcrete, fiber quantities may be slightly higher t
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