1、Report on the Use of Fly Ash in Concrete Reported by ACI Committee 232 ACI 232.2R-18First Printing April 2018 ISBN: 978-1-64195-006-0 Report on the Use of Fly Ash in Concrete Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced
2、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 ambiguities, omissions, and errors in these documents.
3、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 are requested to contact ACI via the errata websi
4、te at http:/concrete.org/Publications/ DocumentErrata.aspx. Proper use of this document includes periodically checking for errata 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 limitations of its c
5、ontent 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 publication is provi
6、ded “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, indirect, inciden
7、tal, 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 involved with its us
8、e. 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 limited to,
9、United States Occupational Safety and Health Administration (OSHA) health and safety standards. Participation by governmental representatives in the work of the American Concrete Institute and in the development of Institute standards does not constitute governmental endorsement of ACI or the standa
10、rds that it develops. Order information: ACI documents are available in print, by download, through electronic subscription, or reprint and may be obtained by contacting ACI. Most ACI standards and committee reports are gathered together in the annually revised the ACI Collection of Concrete Codes,
11、Specifications, and Practices. American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331 Phone: +1.248.848.3700 Fax: +1.248.848.3701 www.concrete.orgFly ash is used in concrete and other portland cement-based systems primarily because of its pozzolanic and cementitious prop- er
12、ties. These properties contribute to strength gain and are known to improve the performance of fresh and hardened concrete, mortar , and grout. The use of fly ash typically results in more economical concrete construction. This report gives an overview of the origin and properties of fly ash, its ef
13、fect on the properties of hydraulic cement concrete, and the selection and use of fly ash in the production of hydraulic cement concrete and concrete products. Information and recommenda- tions concerning the selection and use of Class C and Class F fly ashes conforming to the requirements of ASTM C
14、618 are provided. Topics covered include a detailed description of the composition of fly ash, the physical and chemical effects of fly ash on properties of concrete, guidance on the handling and use of fly ash in concrete construction, use of fly ash in the production of concrete products and speci
15、alty concretes, and recommended procedures for quality control. High-volume fly ash concrete is covered in a general way in this report; readers can consult ACI 232.3R for more information. Keywords: alkali-aggregate reaction; controlled low-strength material; durability; fly ash; mass concrete; poz
16、zolan; sulfate resistance; sustain- ability; workability. CONTENTS CHAPTER 1INTRODUCTION, SCOPE, SOURCES, AND SUSTAINABILITY, p. 2 1.1Introduction, p. 2 1.2Scope, p. 3 1.3Source of fly ash, p. 3 1.4Fly ash and sustainability, p. 7 CHAPTER 2DEFINITIONS, p. 9 CHAPTER 3FLY ASH COMPOSITION, p. 9 3.1Gene
17、ral, p. 9 3.2Chemical composition, p. 10 3.3Crystalline constituents, p. 11 3.4Glassy constituents, p. 13 3.5Physical properties, p. 15 3.6Chemical activity of fly ash in hydraulic cement concrete, p. 17 3.7Future research needs, p. 18 Karthik H. Obla, Chair Robert E. Neal, Vice Chair Michael D. A.
18、Thomas, Vice Chair Lawrence L. Sutter, Secretary ACI 232.2R-18 Report on the Use of Fly Ash in Concrete Reported by ACI Committee 232 Thomas H. Adams Gregory S. Barger Dale P. Bentz James C. Blankenship Julie K. Buffenbarger Ramon L. Carrasquillo Barry A. Descheneaux Jonathan E. Dongell John M. Fox
19、Thomas M. Greene Harvey H. Haynes James K. Hicks R. Doug Hooton Morris Huffman James S. Jensen Tilghman H. Keiper Steven H. Kosmatka Adrian Marc Nacamuli Bruce W. Ramme Steve Ratchye Michael D. Serra Ava Shypula Boris Y . Stein Oscar Tavares Paul J. Tikalsky Thomas J. Van Dam Craig R. Wallace Orvill
20、e R. Werner Consulting Members Mark A. Bury James E. Cook Dean M. Golden William Halczak G. Terry Harris Sr. Jan R. Prusinski Harry C. Roof Della M. Roy Special acknowledgements to M. U. Christiansen and K. A. MacDonald for their contributions to this report. ACI Committee Reports, Guides, and Comme
21、ntaries 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 applicat
22、ion 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 docu
23、ment 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 232.2R-18 supersedes ACI 232.2R-03 and was adopted and published April 2018. Copyright 2018, 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. 1CHAPTER 4EFFECTS OF FLY ASH ON CONCRETE, p. 18 4.1Effects on properties of fresh concrete, p. 18 4.2Effects on properties of hardened concrete, p. 20 CHAPTER 5CONCRETE MIXTURE PROPORTIONING, p. 26 5.1General, p. 2
26、6 5.2Considerations in mixture proportioning, p. 27 CHAPTER 6FLY ASH SPECIFICATIONS, TEST METHODS, AND QUALITY ASSURANCE/QUALITY CONTROL, p. 27 6.1Introduction, p. 27 6.2Chemical requirements, p. 28 6.3Physical requirements, p. 29 6.4General specification provisions, p. 30 6.5Methods of sampling and
27、 testing, p. 30 6.6Source quality control, p. 30 6.7Startup, oil, and stack additives, p. 31 6.8Rapid quality control tests, p. 32 CHAPTER 7FLY ASH IN CONCRETE CONSTRUCTION, p. 32 7.1Ready mixed concrete, p. 32 7.2Concrete pavement, p. 32 7.3Mass concrete, p. 33 7.4Roller-compacted concrete, p. 33 7
28、.5Self-consolidating concrete, p. 33 7.6High-volume fly ash concrete, p. 34 7.7High-performance concrete, p. 34 7.8Long-life structures, p. 34 7.9Bulk handling and storage, p. 35 7.10Batching, p. 36 CHAPTER 8FLY ASH IN CONCRETE PRODUCTS, p. 36 8.1Concrete masonry units, p. 36 8.2Concrete pipe, p. 37
29、 8.3Precast/prestressed concrete products, p. 37 8.4No-slump extruded hollow core slabs, p. 38 8.5Concrete tile, p. 38 8.6Miscellaneous concrete products, p. 38 CHAPTER 9OTHER USES OF FLY ASH, p. 38 9.1Grouts and mortar, p. 38 9.2Controlled low-strength material, p. 39 9.3Soil cement, p. 39 9.4Plast
30、ering, p. 39 9.5Cellular concrete, p. 39 9.6Shotcrete, p. 39 9.7Waste management, p. 40 9.8Cements, p. 40 CHAPTER 10REFERENCES, p. 40 Authored documents, p. 41 APPENDIX ARAPID QUALITY CONTROL TESTS, p. 54 A.1Loss on ignition, p. 54 A.2Carbon analysis, p. 54 A.3Particle size, p. 54 A.4Color, p. 55 A.
31、5Density (specific gravity), p. 55 A.6Fly ash adsorption, p. 55 A.7Organic material, p. 55 A.8CaO content, p. 55 A.9Presence of hydrocarbons (startup oil), p. 55 A.10Presence of ammonia (precipitator additive), p. 55 A.11Calorimetry, p. 55 CHAPTER 1INTRODUCTION, SCOPE, SOURCES, AND SUSTAINABILITY 1.
32、1Introduction Fly ash, a material resulting from the combustion of pulverized coal, is widely used as a cementitious and pozzo- lanic ingredient in concrete and related products. Fly ash is introduced in concrete either as a separately batched material (ASTM C618, Class C or F) or as a component of
33、blended cement (ASTM C595/C595M; ASTM C1157/C1157M; ASTM C1600/C1600M). Fly ash possesses pozzolanic properties similar to the natu- rally occurring pozzolans of volcanic or sedimentary origin found in many parts of the world. Two thousand years ago, the Romans mixed volcanic ash with lime, aggregat
34、e, and water to produce mortar and concrete (Vitruvius 1960). In modern concrete, fly ash combines with calcium hydroxide (Ca(OH) 2 , also known as portlandite, which predominately results from the hydration of portland cement, and with water to form additional cementing product. This process, calle
35、d the pozzolanic reaction, creates a finer pore structure, which in turn increases the durability of mortar and concrete. All fly ashes exhibit pozzolanic properties to some extent. However, some fly ashes also display varying degrees of cementitious properties without the addition of Ca(OH) 2or hyd
36、raulic cement. The cementitious nature of the latter type of fly ash is primarily attributed to the presence of reactive constituents such as calcium aluminate and calcium silicate phases, and calcium oxide. The role of fly ash in concrete with hydraulic cement is summarized as: a) Calcium and alkal
37、i hydroxides that are released into solution in the pore structure of the paste by hydrating cement combine with the pozzolanic phases of fly ash, to form additional calcium silicate hydrate (C-S-H) gel (cementing matrix) b) The heat of hydration helps to initiate the pozzolanic reaction and contrib
38、utes to the rate of the reaction When concrete containing fly ash is cured, fly ash reac- tion products fill spaces originally occupied by mixing water but not filled by the hydration products of the cement, thus reducing the concrete permeability to fluids (Manmohan and Mehta 1981). The slower reac
39、tion rate of fly ash, when compared with hydraulic cement, limits the amount of early heat generation and the detrimental effect of early American Concrete Institute Copyrighted Material www.concrete.org 2 REPORT ON THE USE OF FLY ASH IN CONCRETE (ACI 232.2R-18)temperature rise in massive concrete s
40、tructures. Concrete proportioned with fly ash can develop properties that are not achievable through the use of hydraulic cement alone. 1.1.1 HistoryFly ash from coal-burning electric power plants became readily available in the 1930s and, shortly thereafter, the study of fly ash for use in hydrauli
41、c cement concrete began (Davis et al. 1937; Stanton 1940). This early research served as the foundation for initial specifications, methods of testing, and use of fly ash. Abdun-Nur (1961) covers much of the early history and technology of using fly ash in construction and includes an annotated bibl
42、iography (1934-1959). Since this early work, much research has been performed regarding alkali-silica reaction (ASR) mitigation using fly ash. A recent summary is provided by Thomas et al. (2013). Initially, fly ash was used as a partial replacement of hydraulic cement, which is typically the most e
43、xpensive manufactured component of concrete. As fly ash usage increased, researchers recognized that fly ash could impart beneficial properties to concrete. Additional research was done on the reactivity of fly ash with calcium and alkali hydroxides in portland cement paste, and the ability of fly a
44、sh to act as a mitigator of deleterious alkali-silica reactions was identified (Davis et al. 1937). Other research has shown that fly ash often improves concretes resistance to deteriora- tion from sulfates (Dunstan 1976, 1980; Tikalsky et al. 1992; Tikalsky and Carrasquillo 1993). Fly ash also incr
45、eases the workability of fresh concrete and reduces the peak tempera- ture of hydration in mass concrete. The beneficial aspects of fly ash were especially notable in the construction of large concrete dams (Mielenz 1983). Some major projects, including the Thames Barrier in the UK (Newman and Choo
46、2003) and the Upper Stillwater Dam in the United States (Poole 1995), incorporated 50 and 65 percent mass replacement of hydraulic cement with fly ash to reduce heat generation and decrease permeability, respectively. The Iraivan Temple, built in Kauai, HI, in 1999, has a foundation composed of high
47、-volume fly ash (HVFA) concrete with an estimated service life of 1000 years (Mehta and Langley 2000). This concept of HVFA concrete was adopted for foundation construction of at least two additional temples in the United State: one located in Chicago, IL, and the other in Houston, TX (Malhotra and
48、Mehta 2012). In addition, numerous projects in the United States have used HVFA concrete for sustainable construction. More information on HVFA usage is available in Chapter 7 and ACI 232.3R. A new generation of coal-fired power plants were built in the United States during the late 1960s and 70s us
49、ing effi - cient coal mills and state-of-the-art pyroprocessing tech- nology. These plants produce fly ash with a smaller average particle size and lower carbon content. Fly ash containing high levels of calcium oxide became available because of the use of western U.S. coal sources, typically subbituminous and lignite. Enhanced economics and improved technologies, both material- and mechanical-based, have led to a greater use of fly ash throughout the ready mixed concrete industry. Exten - sive research has led t
