ACI 440.9R-2015 Guide to Accelerated Conditioning Protocols for Durability Assessment of Internal and External Fiber-Reinforced Polymer (FRP) Reinforcement.pdf

1、Guide to Accelerated Conditioning Protocols for Durability Assessment of Internal and External Fiber-Reinforced Polymer (FRP) ReinforcementReported by ACI Committee 440ACI 440.9R-15First PrintingMay 2015ISBN: 978-1-942727-17-0Guide to Accelerated Conditioning Protocols for Durability Assessment of I

2、nternal and External Fiber-Reinforced Polymer (FRP) ReinforcementCopyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or other distribution and storage m

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11、nic subscription, or reprint and may be obtained by contacting ACI.Most ACI standards and committee reports are gathered together in the annually revised ACI Manual of Concrete Practice (MCP).American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331Phone: +1.248.848.3700Fax: +1.2

12、48.848.3701www.concrete.orgFiber-reinforced polymer (FRP) composites, when designed, fabri-cated, and installed, provide a sustainable and durable reinforce-ment system for concrete. This document presents guidance for assessing the durability performance of internal and external FRP composite reinf

13、orcement using accelerated conditioning protocols (ACPs) in combination with standard test methods for mechanical properties. The objective of ACPs is to enable manufacturers to characterize the durability of their FRP composite products and encourage researchers and testing laboratories to adopt co

14、mmon test protocols to build a meaningful database of durability testing of FRP materials. Results of the tests conducted using the recom-mended ACPs are not intended to be used in the design of FRP composites as concrete reinforcement. In the future, however, when the relationship between field per

15、formance and ACPs is better understood, ACPs may be refined to allow use in quality control and design.Keywords: accelerated conditioning; bond; durability; externally bonded; fiber-reinforced polymer composites; modulus of elasticity.CONTENTSCHAPTER 1INTRODUCTION AND SCOPE, p. 21.1Introduction, p.

16、21.2Scope, p. 2Carol K. Shield, Chair William J. Gold, SecretaryACI 440.9R-15Guide to Accelerated Conditioning Protocols for Durability Assessment of Internal and External Fiber-Reinforced Polymer (FRP) ReinforcementReported by ACI Committee 440Tarek AlkhrdajiRussell GentryMaria E. Lopez de MurphyRu

17、dolf SeracinoCharles E. BakisNabil F. GraceIbrahim M. MahfouzVenkatesh SeshappaLawrence C. BankMark F. GreenAmir MirmiranPedro F. SilvaAbdeldjelil BelarbiZareh B. GregorianJohn J. Myers*Samuel A. Steere IIIBrahim BenmokraneDoug D. GremelAntonio NanniJennifer E. Tanner*Luke A. BisbyShawn P. GrossAyma

18、n M. OkeilJay ThomasGregg J. BlaszakH. R. Trey Hamilton, III*Carlos E. OspinaHoussam A. ToutanjiHakim BouadiIssam E. HarikRenato ParrettiJ. Gustavo TumialanTimothy E. BradberryKent A. HarriesMaria A. PolakMilan VatovecVicki L. BrownMark P. HendersonMax L. PorterDavid WhiteJohn P. BuselBohdan N. Hore

19、czkoAndrea ProtaSarah E. WittRaafat El-HachaRavindra KanitkarHayder A. RasheedGarth J. FallisYail Jimmy KimSami H. RizkallaAmir Z. FamMichael W. LeeRajan SenConsulting MembersP. N. BalaguruCraig A. BallingerHarald G. F. BudelmannC. J. BurgoyneRami M. ElhassanDavid M. GaleSrinivasa L. IyerKoichi Kish

20、itaniHoward S. KligerKyuichi MaruyamaAntoine E. NaamanHajime OkamuraMark A. PostmaFerdinand S. RostasySurendra P. ShahMohsen ShahawyYasuhisa SonobeMinoru SugitaLuc R. TaerweRalejs TepfersTaketo UomotoPaul Zia_*Chairs of the subcommittee who prepared this document.Deceased.ACI Committee Reports, Guid

21、es, and Commentaries are intended for guidance in planning, designing, executing, 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

22、 the application of the material it contains. The American Concrete Institute disclaims 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

23、in this document are desired by the Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer.ACI 440.9R-15 was adopted and published May 2015.Copyright 2015, American Concrete Institute.All rights reserved inc

24、luding 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 or visual reproduc-tion or for use in any knowledge or retrieval system or device, unless p

25、ermission in writing is obtained from the copyright proprietors.1CHAPTER 2NOTATION AND DEFINITIONS, p. 32.1Notation, p. 32.2Definitions, p. 3CHAPTER 3DURABILITY OF FIBER-REINFORCED POLYMER COMPOSITES, p. 4CHAPTER 4ACCELERATED CONDITIONING, p. 44.1Background, p. 44.2Accelerated conditioning protocols

26、, p. 54.3Mass change, p. 5CHAPTER 5FIBER-REINFORCED POLYMER REINFORCING BAR TESTS, p. 55.1Sustained bending stress test, p. 5CHAPTER 6EXTERNALLY BONDED FIBER-REINFORCED POLYMER TESTS, p. 66.1Specimen fabrication and preparation, p. 66.2Beam bond test, p. 86.3Pull-off bond test, p. 96.4Tensile test o

27、f fiber-reinforced polymer, p. 9CHAPTER 7FUTURE WORK AND RECOMMENDATIONS, p. 9CHAPTER 8REFERENCES, p. 10Authored documents, p. 10CHAPTER 1INTRODUCTION AND SCOPE1.1IntroductionThis document is a guide to the assessment of the dura-bility performance of internal and external fiber-reinforced polymer (

28、FRP) composite reinforcement using accelerated conditioning protocols (ACPs) in combination with stan-dard test methods for mechanical properties. The purpose of this guide is to document ACPs so that a standardized method can be created to gather data to eventually be used as a screening or accepta

29、nce tool.FRP composites are increasingly being used in infra-structure applications as reinforcing bars and externally bonded reinforcement for strengthening reinforced concrete elements. The use of FRP composites is predicated on perfor-mance attributes linked to their light weight, high stiffness-

30、to-weight and strength-to-weight ratios, ease of installation in the field, potential low system cost, and potentially high overall durability.FRP composites are used by many industries, including automotive, marine, and aerospace. They have success-fully been applied in pipelines, underground stora

31、ge tanks, building faades, and as architectural components. The materials, loading conditions, and environments seen in many infrastructure applications, however, are unique. Anecdotal evidence provides substantial reason to believe that, if appropriately designed and fabricated, FRP compos-ites can

32、 provide longer service life and lower maintenance costs than steel-reinforced structures.FRP composites have been in use as concrete reinforce-ment since the 1980s. Consequently, long-term performance field data are limited, making it essential that potential vulnerabilities regarding FRP durabilit

33、y be identified and addressed early to ensure expected long-term service. One means to identify long-term vulnerability is through the use of accelerated conditioning. Few standard protocols for conducting durability testing exist, making it difficult to draw detailed conclusions from the present da

34、tabase of test results generated over the past two decades. Comparing tests conducted at different laboratories is often complicated by the large number of variables among tests.FRP composite reinforcement embedded in concrete will experience different environmental influences than those experienced

35、 by externally bonded FRP composite reinforce-ment. Externally bonded FRP composite reinforcement is typically exposed directly to ambient environmental condi-tions where embedded reinforcement is not. In many appli-cations, the bond of externally bonded FRP composite rein-forcement is critical to t

36、he short- and long-term structural performance of the system. Due to the fundamental differ-ence in exposure conditions of internal and external FRP composite reinforcement, different ACPs and mechanical testing for internal and external FRP composite reinforce-ment are necessary. In either case, du

37、rability, in the context of this guide, is defined as a measure of the retention of FRP physical and mechanical properties when exposed to the ACP environments for the prescribed duration.An overview of the evaluation process includes the following four elements:1) Specimen fabrication and preparati

38、onProcess used to fabricate the specimen and prepare it for exposure to the ACP.2) Accelerated conditioning protocolSets out the parameters for the environment and stress, including dura-tion, to which the specimen will be exposed (Chapter 4). Additional control specimens are stored in ambient labor

39、a-tory conditions.3) Mechanical testingTests the accelerated conditioned (AC) and control specimens following the exposure period. Testing is completed under unexposed conditions (Chapters 5 and 6).4) Residual mechanical property determinationThe method used to evaluate the effect of ACP on mechanic

40、al properties (Chapters 5 and 6).1.2ScopeThis document provides guidance on using ACPs and associated standard mechanical test methods to assess the durability of FRP composite reinforcement for concrete with the objective to enable manufacturers to characterize the durability of their FRP products

41、and to encourage researchers and testing laboratories to adopt common test protocols to build a meaningful database of durability test results for FRP materials. Results of the tests conducted using the recommended protocols are not intended for use directly in the design of FRP composites. They are

42、 meant to generate a database of consistent test results that can be American Concrete Institute Copyrighted Material www.concrete.org2 ACCELERATED CONDITIONING PROTOCOLS FOR DURABILITY ASSESSMENT OF FRP REINFORCEMENT (ACI 440.9R-15)used in the future to refine the environmental factors recom-mended

43、 in ACI 440.1R, 440.2R, and 440.7R. Recommended environmental reduction factors used in the design of FRP composite reinforcement are provided in ACI 440.1R and 440.2R and are outside the scope of this guide.The results of the conditioning and testing recommended in this guide are not intended to be

44、 useful in the prediction of service life. The use of these methods in conjunction with field evaluations of the performance of structures with FRP composite reinforcement in service conditions is encouraged. Future correlation of accelerated methods with field perfor-mance can help validate and imp

45、rove confidence in their use.Physicochemical tests that measure the changes in the physical and chemical properties of FRP materials can also be useful in assessing degradation of the material and its constituents after being subjected to the ACPs described in this guide.CHAPTER 2NOTATION AND DEFINI

46、TIONS2.1Notationb = cross-sectional width of beam specimenEL1= average elastic modulus of unexposed control spec-imens, psi (MPa)EL2= average elastic modulus of accelerated conditioned specimens, psi (MPa)fu= ultimate tensile strength of fiber-reinforced polymer reinforcing bar, psi (MPa)Fp1= averag

47、e pull-off bond strength of unexposed control specimens, lbf (N)Fp2= average pull-off bond strength of accelerated condi-tioned specimens, lbf (N)Fu1= average tensile strength of unexposed control spec-imens, lbf (N)Fu2= average tensile strength of accelerated conditioned specimens, lbf (N)h = cross

48、-sectional height of beam specimenL = length of beam specimenPb1= average beam strength of unexposed control speci-mens, lbf (N)Pb2= average beam strength of accelerated conditioned specimens, lbf (N)Reb= beam bond retention, percentRem= elastic modulus retention, percentRep= pull-off bond retention

49、, percentRes= ultimate strain retention, percentRet= tensile strength retention, percentW0= average unexposed specimen mass, gW1= average specimen mass of accelerated conditioned specimens, gu1= average ultimate strain of unexposed control specimensu2= average ultimate strain of accelerated conditioned specimens2.2DefinitionsACI provides a comprehensive list of definitions through an online resource, “ACI Concrete Terminology,” http:/concrete.org/tools/concreteterminology.aspx. Defini-tions provided herein complement that source.aramid fib