1、Guide to Placing Concrete by Pumping Methods Reported by ACI Committee 304 ACI 304.2R-17First Printing October 2017 ISBN: 978-1-945487-82-8 Guide to Placing Concrete by Pumping Methods Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be r
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11、crete Practice (MCP). American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331 Phone: +1.248.848.3700 Fax: +1.248.848.3701 www.concrete.orgThis guide discusses the use of pumps for transporting and placing concrete. Rigid and flexible pipelines, couplings and other acces- sori
12、es, and the various types of concrete pumps are discussed. The importance of proportioning a pumpable concrete mixture is emphasized with reference to sources for further direction on its design. Evaluation of trial mixtures to ensure pumpability and strength is encouraged. Of specific importance is
13、 a discussion on the use of lightweight aggregates. Methods to saturate these aggre- gates and provide a consistent moisture content are discussed. Preconstruction planning for equipment placement and line routing are emphasized. Discussions on achieving a consistent mixture and its critical importa
14、nce are also addressed. Keywords: blockage; boundary layer; concrete pump; coupling; mixture design; pipeline; placing boom; preprimed; pumpability; reverse pumping; valve. CONTENTS CHAPTER 1INTRODUCTION AND SCOPE, p. 2 1.1Introduction, p. 2 1.2Scope, p. 2 CHAPTER 2DEFINITIONS, p. 2 CHAPTER 3PUMPING
15、 CONCRETE, p. 2 3.1Mixture component distribution, p. 2 3.2Disruptions to flow, p. 3 CHAPTER 4PUMPING EQUIPMENT AND COMPONENTS, p. 4 4.1Piston pumps, p. 4 4.2Valve types, p. 4 4.3Trailer pumps, p. 5 4.4Truck-mounted concrete pumps, p. 5 4.5Separate placing booms, p. 6 4.6Specialized equipment, p. 6
16、4.7Pipeline and accessories, p. 6 4.8Flexible system hose types and applications, p. 9 4.9Concrete placing system accessories, p. 9 CHAPTER 5PUMPABLE CONCRETE, p. 11 5.1Basic considerations, p. 11 5.2Normalweight aggregate, p. 11 5.3Lightweight aggregate concrete, p. 12 5.4Water and slump, p. 12 5.5
17、Cementitious materials, p. 14 5.6Admixtures, p. 14 5.7Fiber reinforcement, p. 14 5.8Trial mixtures and pumpability testing, p. 15 5.9Estimating performance, p. 15 Larry G. Leper, Chair ACI 304.2R-17 Guide to Placing Concrete by Pumping Methods Reported by ACI Committee 304 Hakim S. Abdelgader David
18、J. Akers Casimir J. Bognacki David A. Burg Manjit S. Chopra Bernard J. Eckholdt III J. Mitchell Engelstead Michael R. Gardner Daniel J. Green Neil R. Guptill Terence C. Holland Tarek S. Khan Gary R. Mass Larry W. Matejcek Avi A. Mor Mike Murray Dipak T. Parekh James S. Pierce Jorge L. Quiros Jr. Roy
19、ce J. Rhoads James M. Shilstone Jr. Boris Y . Stein Samuel X. Yao Richard Yelton Consulting Member Thomas R. Clapp The committee would like to give special acknowledgement to associate member J. Bury, Chair of the subcommittee that prepared this document, for his considerable contribution to its dev
20、elopment. ACI 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
21、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
22、in 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 304.2R-17 supersedes ACI 304.2R-96 and was adopted and published October
23、2017. Copyright 2017, 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 or visual reprodu
24、ction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors. 1CHAPTER 6FIELD PRACTICES, p. 15 6.1General, p. 15 6.2Pipeline concrete placement, p. 16 6.3Powered boom placement, p. 17 6.4Equipment and operational safety, p.
25、18 6.5Reduction in air content, p. 18 CHAPTER 7FIELD CONTROL, p. 19 CHAPTER 8REFERENCES, p. 19 Authored documents, p. 19 CHAPTER 1INTRODUCTION AND SCOPE 1.1Introduction Pumping concrete through metal pipelines by piston pumps was introduced to the United States in Milwaukee, WI, in 1933 (Ball 1933).
26、 This concrete pump used mechan- ical linkages to operate, and usually pumped through pipe- lines 6 in. (150 mm) or larger in diameter. Many new developments have since been made in the concrete pumping field. These include new and improved pumps, truck-mounted and stationary placing booms, and pipe
27、lines and hoses that withstand higher pumping pressures. Pumps are available with maximum theoretical output capaci- ties of over 250 yd 3 /h (190 m 3 /h). As a result of these innova- tions, concrete placement by pumps has become one of the most widely used practices of the construction industry. T
28、he construction industry recognizes that concrete pumping is useful when space for construction equipment is limited. Cranes and hoists are freed up and other crafts can work unhampered while pumping is in progress. Concrete pumps are designed to deliver the best combination of volume output and con
29、crete line pressure possible. How well the pump performs in an application depends on many factors, both internal and external to the equipment itselffor example, ambient temperature influences pump performance. Pipe diameter, pumping direction both for vertical and horizontal distance, and concrete
30、 mixture char- acteristics also have an effect. As construction designs and projects become more sophisticated, such as requiring higher strength and greater durability, concrete mixture design today is more complex than what was traditionally placed (Putzmeister America, Inc 2010; American Concrete
31、 Pumping Association 2007, 2010, 2011b). Pumpability is one consideration the contractor can request from the designer when specifying mixtures. Engi- neered mixtures, using special materials and processing, must consider design details including final strength, curing characteristics, site conditio
32、ns such as underwater place- ment, material and handling expenses, flow characteristics, delivery/placement, and sustainability impacts. In cases where these features are in direct conflict, a compromise or alternate solution is necessary. Given the popularity and benefits of placement by pumping, i
33、t could become critical to a specific application that the components and proportions of a mixture be designed with consideration of pumpability. There are many variables that could affect the successful pumping of a mixture in an application, including the specific requirements of a specific combin
34、ation of materials, equipment components, and installation circumstances, of which several will be discussed in more detail in this guide. This guide discusses concrete placement using the pumping method and how it affects the supplied concrete mixture when considering pumpability in mixture design,
35、 and with the goal to obtain optimum concrete pumping results. 1.2Scope This guide for concrete pumping discusses equipment use, proper mixtures for good pumpability, and field prac- tices. References cited provide more detailed information on specific subjects. This guide does not address shotcreti
36、ng or pumping of nonstructural insulating or cellular concrete. CHAPTER 2DEFINITIONS ACI provides a comprehensive list of definitions through an online resource, “ACI Concrete Terminology”, https:/ www.concrete.org/store/productdetail.aspx?ItemID=CT13. Definitions provided herein complement that sou
37、rce. boundary layerthin coating of mortar fraction that lines the inner pipeline wall during pumping. degree of pumpabilitythe amount of resistance of a specific concrete mixture to being pumped through a delivery pipeline. pumpabilitycapability of a specific concrete mixture to being pumped through
38、 a delivery pipeline. relative movementability of concrete components to navigate small distances within the mixture and to position differently compared to the other components. stable concreteconcrete mixture that resists the tendency to segregate. CHAPTER 3PUMPING CONCRETE Pumped concrete moves a
39、s a cylinder riding on a thin lubricating film of grout or mortar on the inside diameter of the pipeline. Before pumping begins, the entire pipe- lines interior diameter must be coated with either grout or a specialized commercial primer using the methods for 100 percent coating of the pipe walls as
40、 recommended by the manufacturer. Once concrete flow through the pipeline is established, the lubrication will be maintained as long as pumping continues with a properly proportioned and consistent mixture. A steady supply of pumpable concrete, defined as a mixture that is capable of being pumped th
41、rough a hose or pipe, is necessary for satisfactory pumping (U.S. Bureau of Reclamation 1981). A pumpable concrete, such as conventional concrete, requires good quality control; that is, it is uniform, has properly graded aggregate, and its mate- rials are uniformly batched and mixed thoroughly. 3.1
42、Mixture component distribution 3.1.1 Boundary layerFrom the concrete pumps delivery cylinder to the point-of-placement end hose, effective and efficient concrete pumping depends on minimizing any American Concrete Institute Copyrighted Material www.concrete.org 2 GUIDE TO PLACING CONCRETE BY PUMPING
43、 METHODS (ACI 304.2R-17)drag caused by the inside wall of the delivery vessel. One suggestion is to have the inside wall continuously bordered by a boundary layer that gives the least resistance to move- ment as possible. At the start of each placement or “pour,” to which it is sometimes referred, t
44、his boundary layer is achieved by priming the line with a thin film of grout or commercial primer. This coating provides a slicker surface with lower frictional resistance for the mixture to glide along than would a steel pipe or rubber hose. To ensure that this low resistance-force action continues
45、, the mixture should have enough mortar content to maintain a boundary layer between the body of mixture and the pipeline wall. This is similar to the need for a certain level of work- ability resulting from the mortar fraction when finishing concrete. A boundary layer allows the concrete mass to mo
46、ve through the pipeline without the aggregates scraping the pipe wall. If scraping occurs, the contact friction causes resistance to pumping. The magnitude of the pumping resis- tance depends on the aggregate, pipe wall composition, and line pressure pushing the aggregate into the wall. This resis-
47、tance is somewhat self-perpetuating because the line pres- sure increases the friction of the concrete being pumped, which in turn increases the amount of pressure in the line. The boundary layer also increases the useful life of the pipeline. If the pipeline wall is not subjected to frictional scra
48、ping, it is more likely to remain coated and less likely to be worn down or damaged. This extends the amount of material that can be safely pumped through it before a replacement is needed. 3.1.2 Mortar contentIn addition to the need for a mortar-based boundary layer, the remaining concrete mass als
49、o requires a minimum amount of mortar to transport effi- ciently through the pipeline (Fig. 3.1.2). With a properly proportioned mortar content, the concrete mixture will: a) Provide enough mortar fraction to suspend the aggre- gate during pumping, as well as facilitate finishing and strength development. b) Quickly achieve a preferred arrangement with all components located in positions that best arranges them to both physical and electrostatic attraction/repulsion charac- teristics. This spatial arrangement remains intact unless it
