1、Report on Service Life Prediction Reported by ACI Committee 365 ACI 365.1R-17First Printing September 2017 ISBN: 978-1-945487-74-3 Report on Service Life Prediction Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or copied,
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11、. American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331 Phone: +1.248.848.3700 Fax: +1.248.848.3701 www.concrete.orgThis report presents information to the owner and design profes- sional on the service life prediction of new and existing concrete structures. Key factors co
12、ntrolling the service life of concrete and methodologies for evaluating the condition of the existing concrete structures, including definitions of key physical proper- ties, are also presented. This report assists in the application of available methods and tools to predict the service life of exis
13、ting structures and provides procedures that can be taken at the design and construction stage to increase the service life of new struc- tures. Techniques for predicting the service life of concrete and the relationship between economics and the service life of struc- tures are discussed. Examples
14、provided discuss which service life techniques are applied to concrete structures or structural compo- nents. Needed developments to improve the reliability of service life predictions are also identified. Keywords: chemical attack; construction; corrosion; design; durability; rehabilitation; repair
15、; service life; sustainability. CONTENTS CHAPTER 1INTRODUCTION AND SCOPE, p. 2 1.1Introduction, p. 2 1.2Scope, p. 3 CHAPTER 2DEFINITIONS AND NOTATION, p. 3 2.1Definitions, p. 3 2.2Notation, p. 4 CHAPTER 3ENVIRONMENT, DESIGN, AND CONSTRUCTION CONSIDERATIONS, p. 5 3.1Introduction, p. 5 3.2Environmenta
16、l considerations, p. 5 3.3Design and structural loading considerations, p. 10 3.4Interaction of structural load and environmental effects, p. 11 3.5Construction-related considerations, p. 12 CHAPTER 4IN-SERVICE INSPECTION, CONDITION ASSESSMENT, AND REMAINING SERVICE LIFE, p. 13 4.1Introduction, p. 1
17、3 4.2Preliminary condition assessment, p. 14 4.3Detailed structural assessments, p. 17 4.4Inspection and maintenance to maintain or predict structural reliability, p. 18 CHAPTER 5METHODS FOR PREDICTING THE SERVICE LIFE OF CONCRETE STRUCTURES, p. 19 5.1Introduction, p. 19 5.2Approaches for predicting
18、 service life of new concrete structures, p. 20 5.3Prediction of remaining service life of existing concrete structures, p. 26 5.4Predictions for existing structures based on extrapo- lations, p. 27 Evan C. Bentz, Chair Kyle D. Stanish, Secretary ACI 365.1R-17 Report on Service Life Prediction Repor
19、ted by ACI Committee 365 Muhammed P. A. Basheer Neal S. Berke Shrinivas B. Bhide David N. Bilow Larry D. Church Carolyn M. Hansson R. Doug Hooton O. Burkan Isgor Anthony N. Kojundic Zoubir Lounis Tracy D. Marcotte David B. McDonald Matthew A. Miltenberger Mohamad Nagi Dan J. Naus Karthik H. Obla Bru
20、ce G. Smith Michael D. A. Thomas Paul G. Tourney Wael A. Zatar Shengjun Zhou Consulting Members Antonio J. Aldykiewicz Jr. James P . Archibald Francois Chapdelaine David G. Manning Charles D. Pomeroy Jesus Rodriguez Alexander M. Vaysburd Yash Paul Virmani ACI Committee Reports, Guides, and Commentar
21、ies 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 the application
22、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 in this document
23、 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 365.1R-17 supersedes ACI 365.1R-00 and was adopted and published September 2017. Copyright 2017, American Concrete Institute. A
24、ll 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 or visual reproduction or for use in any knowledge or retrieval syste
25、m or device, unless permission in writing is obtained from the copyright proprietors. 15.5Multi-species approaches, p. 27 5.6Summary, p. 28 CHAPTER 6ECONOMIC CONSIDERATIONS, p. 28 6.1Introduction, p. 28 6.2Life cycle cost analysis, p. 29 6.3Governing parameters in LCC analysis, p. 31 6.4Service life
26、 prediction and LCCA of concrete struc- tures, p. 32 6.5Example, p. 32 CHAPTER 7EXAMPLES OF SERVICE LIFE TECHNIQUES, p. 33 7.1Introduction, p. 33 7.2Example 1: Relationship of amount of steel corro- sion to time of spalling, p. 34 7.3Example 2: Use of multiple inputs to calculate life of structure,
27、p. 35 7.4Example 3: When to repair or rehabilitate, p. 36 7.5Example 4: Use of reaction rate to calculate life of sewer pipe, p. 38 7.6Example 5: Estimating service life and maintenance demands of diaphragm wall exposed to saline groundwater, p. 38 7.7Example 6: Application of time-dependent reli- a
28、bility concepts to concrete slab, p. 39 7.8Example 7: Use of stochastic cumulative damage models to predict service life of concrete structures, p. 40 7.9Example 8: Probabilistic service life prediction, p. 41 7.10Example 9: Predicting chloride ingress in a marine environment for concrete with diffe
29、rent cementitious mate- rials, p. 42 7.11Example 10: Multi-ionic finite element transport model (parking structure), p. 43 CHAPTER 8ONGOING WORK AND NEEDED DEVELOPMENTS, p. 45 8.1Introduction, p. 45 8.2Designing for durability, p. 46 8.3Needed developments, p. 47 CHAPTER 9REFERENCES, p. 47 Authored
30、documents, p. 49 CHAPTER 1INTRODUCTION AND SCOPE 1.1Introduction Service life concepts for buildings and structures date back to when early builders found that certain materials and designs lasted longer than others (Davey 1961). Since then, service life predictions of structures, equipment, and oth
31、er components have been generally qualitative and empir- ical. An understanding of the mechanisms and kinetics of many degradation processes of concrete has formed a basis for making quantitative predictions of the service life of concrete structures and components. In addition to actual or potentia
32、l structural collapse, other factors can govern the service life of a concrete structure. This document reports on these service life factors for new and existing concrete structures and components. Historically, three types of service life have been defined (Sommerville 1992): (1) Technical service
33、 life is the time in service until a defined unacceptable state is reached, such as spalling of concrete, unacceptable safety level, or failure of elements. Examples of technical end of service life include: (a) Structural safety is unacceptable due to material degra- dation or exceeding the design
34、load-carrying capacity (b) Severe material degradation, such as extensive corrosion of steel reinforcement (c) Excessive deflection under service loads due to decreased stiffness (2) Functional service life is the time in service until the structure no longer fulfills the functional requirements or
35、becomes obsolete due to change in functional requirements. Examples include: (a) Need for increased clearance, higher axle and wheel loads, or road widening (b) Aesthetics become unacceptablefor example, excessive corrosion staining (c) Functional capacity of the structure is no longer sufficientfor
36、 example, a football stadium with insuf- ficient seating capacity (3) Economic service life is the time in service until replacement of the structure or part of it is more economical than keeping it in service. Examples include: (a) Maintenance requirements exceed available resource limits (b) Repla
37、cement to improve economic opportunities for example, replacing an existing parking garage with a larger one due to increased demand Essentially, decisions concerning the end of service life are related to public safety, serviceability, functionality, and economic considerations. In most cases, the
38、performance, appearance, or capacity of a structure can be upgraded to an acceptable level bearing in mind costs, which are addressed in Chapter 6 of this report. ACI 562, a performance-based code for the repair of struc- tural concrete buildings, has taken the terms for “durability” and “service li
39、fe,” and defined “design service life” (refer to Chapter 2 of this report) such that licensed design profes- sionals can design rehabilitation and repair programs for owners, allowing for extension of service life for a given structure. Regardless of the service life concept, the terms “durability”
40、and “service life” are often erroneously inter- changed. The distinction between the two terms is that dura- bility is about performance for a given time frame in a given environment, and service life is the amount of time to be expected in a given environment or a specific structure. Service life e
41、valuation methodologies have applica- tion both in the design stage of a structurewhere certain parameters are established, such as selection of the water- cementitious materials ratio (w/cm), concrete cover, and admixturesand in the operation phase where inspection and maintenance strategies are de
42、veloped in support of life cycle cost analyses (LCCA) (Zatar 2014). During the American Concrete Institute Copyrighted Material www.concrete.org 2 REPORT ON SERVICE LIFE PREDICTION (ACI 365.1R-17)design stage, there is typically a design service life that is anticipated. This is either implicitly es
43、tablished or explicitly considered. The implicit design life relies on code minimums to achieve satisfactory performance for a typical life of a concrete structure. Explicitly considering a design service life allows the owner more control over the long-term expec- tations for the performance of the
44、 structure, although code minimums still need to be met. Service life design includes the architectural and structural design, selection and design of materials, maintenance plans, and quality assurance and quality control plans for a future structure (RILEM 1986). Service life can be predicted base
45、d on mixture proportioning, including selection of concrete constituents; known material properties; expected service environment; structural detailing, such as concrete cover; construction methods; projected loading history; and the defi- nition of end-of-life. This allows concrete structures to ha
46、ve a reasonable assurance of meeting the specified design service life (Jubb 1992; Clifton and Knab 1989; Sommerville 2003). The acceptance of advanced materials, such as high-perfor- mance concrete, can depend on life cycle cost (LCC) analyses that consider predictions of their increased service li
47、fe. Methodologies are being developed that predict the service life of existing concrete structures (Ahmad 2003; Zatar 2014). To make these predictions, information is required on the present condition of concrete and reinforce- ment, rates of degradation, past and future loading, and defi- nition o
48、f the end-of-life (Clifton 1991). Based on remaining life predictions, economic decisions can be made on whether a structure should be repaired, rehabilitated, or replaced. Service life evaluations have also been used to establish inspection frequencies to minimize expected expenditures (Mori and El
49、lingwood 1994a,b). For rehabilitation and repair programs, this methodology becomes complicated and is not yet well understood, as estimating the service life of a repaired component or structure depends on the type and quality of repair (ACI 546R) as well as the performance of the initial structure, and the materials and systems can vary from traditional concrete and its deterioration mechanisms. Service life comparisons can also be performed by defining a study period over which alternative durability approaches are considered. P
