1、ACI 303R-12Guide to Cast-in-Place Architectural Concrete Practice Reported by ACI Committee 303First PrintingJune 2012Guide to Cast-in-Place Architectural Concrete PracticeCopyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or
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7、ial 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 use. ACI does not mak
8、e 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, United States Occup
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11、oncrete Institute38800 Country Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgISBN 978-0-87031-771-2American Concrete InstituteAdvancing concrete knowledgeThis guide presents recommendations for producing cast-in-place architectural concrete. The import
12、ance of specified materials, forming, concrete placement, curing, additional treatment, inspec-tion, and their effect on the appearance of the finished product are discussed. Architectural concrete requires special construction techniques, materials, and requirements that are unique to each project.
13、 The specific recommendations and information presented in this guide should be used accordingly.Keywords: admixture; aggregate; architectural concrete; beam; bush-hammer; cement; coating; column; consolidation; cracking; curing; deflec-tion; exposed-aggregate finish; finish; form lining; formwork;
14、joint; joint sealant; mixture proportion; pigment; placing; quality control; release agent; repair; retarder; sealant; texture; wall.CONTENTSChapter 1Introduction, p. 2Chapter 2Definitions, p. 2Chapter 3Architectural considerations, p. 33.1Architectural features3.2Architectural design3.3Coatings and
15、 sealers3.4Joint sealants3.5SpecificationsChapter 4Structural considerations, p. 74.1Spalling4.2Deflections4.3Cracking4.4Joints4.5Beams and slabs4.6Columns4.7WallsChapter 5Forms, p. 105.1General5.2MaterialsACI 303R-12Guide to Cast-in-Place Architectural Concrete PracticeReported by ACI Committee 303
16、Chris A. Forster, ChairKeith AhalGeorge F. BatyEugene H. Boeke Jr.Daniel P. DorfmuellerThomas J. GrisingerGardner P. HorstJames M. Shilstone Jr.Michael S. SmithDavid M. SuchorskiClaude B. Trusty Jr.Gregory R. WagnerThe committee would like to thank the late Louis Tallarico for his contribution to th
17、is guide.1ACI Committee Reports, Guides, 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 a
18、nd who will accept responsibility for 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 i
19、n contract documents. If items found 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 303R-12 supersedes ACI 303R-04 and became effective June 2012Copyright 2012
20、, American Concrete InstituteAll 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 repro-duction or for use in a
21、ny knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.5.3Economics5.4Formwork accuracy5.5Form joints5.6Textures and patterns5.7Formwork accessories5.8Form coatings and sealers5.9Form release agents5.10Form removalChapter 6Reinforcement, p
22、. 186.1General6.2Clear space6.3Reinforcement supports and spacers6.4Tie wire6.5Zinc-coated (galvanized) steel reinforcement6.6Epoxy-coated reinforcing barsChapter 7Concrete materials and mixture proportioning, p. 207.1General7.2Materials7.3Proportioning, mixing, and temperature controlChapter 8Placi
23、ng and consolidation, p. 228.1Conveying and placing8.2ConsolidationChapter 9Curing, p. 249.1General9.2Curing in forms9.3Moist curing9.4Membrane curing9.5Hot weather curingChapter 10Treated architectural surfaces, p. 2410.1Surface retarders10.2High-pressure water jet10.3Acid wash10.4Abrasive blasting
24、10.5Tooling or other mechanical treatmentsChapter 11Finishing and final cleanup, p. 2611.1General11.2Tie holes11.3Blemish repair11.4Stain removal11.5Sealers and coatingsChapter 12References, p. 27Appendix AArchitectural concrete photos, p. 29CHAPTER 1INTRODUCTIONThis guide presents recommendations f
25、or cast-in-place architectural concrete that is exposed to view. Architectural concrete requires special care in the selection of concrete materials, forming, placing, and finishing to achieve the desired architectural appearance. Refer to the photos in Appendix A for examples of architectural cast-
26、in-place concrete. Various procedures are recommended for deter-mining requirements of the architect, contractor, concrete producer, and inspector. Critical areas are indicated for special attention, and means for prevention or correction of defects are discussed. Specific surface treatments and spe
27、cial forming techniques are presented. Applicable codes, specifi-cations, and recommendations are given. A good resource for general information about architectural concrete can be found in several papers published in Concrete International (1984(a) to (i); 1988(a) to (h), as well as the Concrete Co
28、nstruction Engineering Handbook (Kenny and Freedman 1997).The information presented in this guide is broad and covers several special conditions for specific architectural concrete. Information that may be applicable for use in producing a specific result may not be applicable to another. The user s
29、hould also be aware that recommendations in this guide are subjective to the means and methods used for accomplishing a specific task for a specific level of architectural effect, and should be tested before use to ensure it will produce the required result. Further research is needed to provide add
30、i-tional information on surface air voids and other construc-tion problems. This guide does not address all the problems associated with architectural concrete.CHAPTER 2DEFINITIONSACI provides a comprehensive list of definitions through an online resource, “ACI Concrete Terminology,” (http:/terminol
31、ogy.concrete.org). Definitions provided herein complement that resource.blemishany superficial defect that causes visible varia-tion from a consistently smooth and uniformly colored surface of hardened concrete.checkingdevelopment of shallow cracks at closely spaced but irregular intervals on the su
32、rface of plaster, cement paste, mortar, or concrete.concrete, architecturalconcrete that will be perma-nently exposed to view and therefore requires special care in the selection of the concrete materials, forming, placing, and finishing to obtain the desired architectural appearance.concrete, cast-
33、in-placeconcrete that is deposited and allowed to harden in the place where it is required to be in the completed structure, as opposed to precast concrete.concrete, exposedconcrete surfaces formed so as to yield an acceptable texture and finish for permanent expo-sure to view. (Refer to concrete, a
34、rchitectural.)finish, exposed-aggregatea decorative finish for concrete work achieved by removing, generally before the concrete has fully hardened, the outer skin of mortar and exposing the coarse aggregate.finish, rubbeda finish obtained by using an abrasive to remove surface irregularities from c
35、oncrete. (Refer to sack rub.)mottlinguneven color shading or blotchiness across a surface.quality controlactions taken by an organization to provide control and documentation over what is being done and what is being provided so that the applicable standard of American Concrete Institute Copyrighted
36、 Materialwww.concrete.org2 GUIDE TO CAST-IN-PLACE ARCHITECTURAL CONCRETE (ACI 303R-12)good practice and the contract documents for the work are followed.sack ruba finish for formed concrete surfaces, designed to produce even texture and fill pits and air holes; after damp-ening the surface, mortar i
37、s rubbed over the surface; then, before the surface dries, a mixture of dry cement and sand is rubbed over it with either a wad of burlap or a sponge-rubber float to remove surplus mortar and fill voids.sandblasta system of cutting or abrading a surface such as concrete by a stream of sand ejected f
38、rom a nozzle at high speed by compressed air; often used for cleanup of horizontal construction joints or for exposure of aggregate in architectural concrete.snap tiea proprietary concrete wall-form tie, the end of which can be twisted or snapped off after the forms have been removed.texturethe patt
39、ern or configuration apparent in an exposed surface, as in concrete and mortar, including rough-ness, streaking, striation, or departure from flatness.CHAPTER 3ARCHITECTURAL CONSIDERATIONS3.1Architectural features3.1.1 General acceptance criteriaArchitecturally acceptable concrete surfaces should be
40、 aesthetically compat-ible with minimal color and texture variations and surface defects when viewed at a distance of approximately 20 ft (6 m) or more, as agreed upon by the architect, owner, and contractor, or as otherwise specified.3.1.2 MeasurementIt is beyond the scope of this guide to establis
41、h precise or definitive rules of measurement. Within any discrete building element or series of like elements, however, a high degree of visual uniformity is generally expected and required. The preconstruction mockup panel would normally be used to establish acceptance criteria (Section 3.5.4).3.1.
42、3 Variations in color and shadingVariations in color and shades within a color can be expected due to the many variables encountered with cast-in-place architectural concrete. These are minimized by: Quality control of ingredients, concrete mixtures, and consistency (Sections 7.2 and 7.3); Uniform c
43、oncrete delivery schedules (Section 8.1.1); Uniformity of form surface, form release agent, applica-tion rate, and formwork reusage, erection, and stripping (Sections 5.10.2 to 5.10.4); Uniform rates of placement and consistent methods of placement and consolidation of concrete (Chapter 8); Placemen
44、t schedules to minimize extreme variations of ambient conditions (Section 8.1.1); Consistent curing procedure and material (Chapter 9); and Properly timed or executed finishing operations (Chapter 11).3.1.4 FinishesSurface textures are grouped into two general classes: Untreated surfaces where the m
45、ortar is the principal visible constituent, and the texture is that which is imparted by the formwork sheathing or form liner; and Surfaces that are mechanically or chemically treated in place by removal of surface mortar to expose the under-lying aggregate, thus wholly or partially obscuring the te
46、xture of the form sheathing or form liner.High-build polymer coatings and cementitious or polymer-modified coatings that obscure both color and texture are not included in this guide.3.2Architectural design3.2.1 General criteriaArchitectural design criteria for readily obtainable and acceptable resu
47、lts should include: Isolation or division of concrete surfaces to allow reuse of formwork modules by the incorporation of rustica-tion or joint patterns, or by the employment of a paneled effect; Systematic planning of construction joints that allows a reusable formwork module and conforms to struct
48、ural requirements; Use of textured form sheathing (face sheets) or form liners, mechanically or chemically textured concrete finishes, or other relief features; and Limitations on the size of panels bounded by rustication or joint patterns; large, smooth, uninterrupted expanses of concrete surfaces
49、should be avoided.3.2.2 Details of architectural design3.2.2.1 Unchamfered cornersAlthough acute- and right-angle corners can be obtained, they are difficult to construct and maintain, especially during construction. Proper consol-idation of the concrete is essential, and self-consolidating concrete (SCC) may be required to achieve a crisp edge (Fig. 3.2.2.1). Forms should be designed and sealed to resist concrete placing pressures, and fabricated such that they can be stripped without damag
