ACI 304 2R-1996 Placing Concrete by Pumping Methods《抽运法浇筑混凝土》.pdf

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1、 304.2R-1ACI 304.2R-96 supersedes ACI 304.2R-91 and became effective January 1, 1996.Copyright 1996, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by anymeans, including the making of copies by any photo process, or by any electronic ormechan

2、ical device, printed or written or oral, or recording for sound or visual repro-duction or for use in any knowledge or retrieval system or device, unless permission inwriting is obtained for the copyright proprietors.ACI Committee Reports, Guides, Standard Practices, andCommentaries are intended for

3、 guidance in planning,designing, executing, and inspecting construction. Thisdocument is intended for the use of individuals who arecompetent to evaluate the significance and limitations of itscontent and recommendations and who will acceptresponsibility for the application of the material it contai

4、ns.The American Concrete Institute disclaims any and allresponsibility for the stated principles. The Institute shall notbe liable for any loss or damage arising therefrom.Reference to this document shall not be made in contractdocuments. If items found in this document are desired by theArchitect/E

5、ngineer to be a part of the contract documents, theyshall be restated in mandatory language for incorporation bythe Architect/Engineer.ACI 304.2R-96(Reapproved 2008)This report describes pumps for transporting and placing concrete. Rigidand flexible pipelines are discussed and couplings and other ac

6、cessoriesdescribed. Recommendations for proportioning pumpable concrete suggestoptimum gradation of aggregates; outline water, cement, and admixturerequirements; and emphasize the need for evaluation of trial mixes forpumpability. The importance of saturating lightweight aggregates isstressed. Sugge

7、stions are given for layout of lines; for maintaining uniformdelivery rate, as well as uniform quality of concrete at the end of the line;and for cleaning out pipelines.This report does not cover shotcreting or pumping of nonstructural insu-lating or cellular concrete.Keywords: admixtures; aggregate

8、 gradation; aggregates; cement content;coarse aggregates; concrete construction; concretes; conveying; couplings;fine aggregates; fineness modulus; lightweight aggregate concrete; light-weight aggregates; mix proportioning; pipeline; placing; placing boom;pozzolans; pumped concrete; pumps; quality c

9、ontrol; water content.CONTENTSChapter 1Introduction, p. 304.2R-2Chapter 2Pumping equipment, p. 304.2R-22.1Piston pumps2.2Types of valves2.3Trailer pumps2.4Truck-mounted concrete pumps2.5Placing booms2.6Specialized equipment 2.7SafetyChapter 3Pipeline and accessories, p. 304.2R-63.1General descriptio

10、n3.2System pressure capacity3.3Rigid placing lineStraight sections, bends, andelbows3.4System connection3.5Flexible systemHose types and applications3.6Concrete placing system accessoriesChapter 4Proportioning pumpable concrete,p. 304.2R-104.1Basic considerations4.2Normal weight aggregate4.3Lightwei

11、ght aggregate concrete4.4Water and slump4.5Cementitious materials4.6Admixtures4.7Fiber reinforcement4.8Trial mixes4.9Testing for pumpabilityChapter 5Field practices, p. 304.2R-195.1General5.2Pipeline concrete placement5.3Powered boom placementPlacing Concrete by Pumping MethodsReported by ACI Commit

12、tee 304Neil R. Guptill,ChairmanDavid J. Akers Robert A. Kelsey*James S. PierceCasimir Bognacki*John C. King Paul E. ReinhartJames L. CopeWilliam C. Krell Royce J. Rhoads*Michael Gardner Gary R. Mass Kenneth L. SaucierDaniel J. Green*Patrick McDowell Paul R. StodolaTerrence C. Holland Dipak T. Parekh

13、 William X. Sypher*Thomas A. Johnson*Roger J. Phares*Robert E. Tobin*Samuel A. Kalat Kevin Wolf*Member of subcommittee that prepared this report.Chairman of subcommittee that prepared this report.304.2R-2 ACI COMMITTEE REPORTFig. 1Piston pump and powered valve pumping trainChapter 6Field control, p.

14、 304.2R-24Chapter 7References, p. 304.2R-247.1Recommended references7.2Cited references7.3Other referencesAppendix 1Metric (SI) system adaptation, p. 304.2R-25CHAPTER 1INTRODUCTIONACI defines pumped concrete as concrete that is transport-ed through hose or pipe by means of a pump. Pumping con-crete

15、through metal pipelines by piston pumps wasintroduced in the United States in Milwaukee in 1933. Thisconcrete pump used mechanical linkages to operate thepump and usually pumped through pipelines 6 in. or larger indiameter.Many new developments have since been made in the con-crete pumping field. Th

16、ese include new and improvedpumps, truck-mounted and stationary placing booms, andpipeline and hose that withstand higher pumping pressures.As a result of these innovations, concrete placement bypumps has become one of the most widely used practices ofthe construction industry.Pumping may be used fo

17、r most concrete construction, butis especially useful where space for construction equipmentis limited. Concrete pumping frees hoists and cranes to de-liver the other materials of construction concurrently withconcrete placing. Also, other crafts can work unhampered byconcrete operations.A steady su

18、pply of pumpable concrete is necessary for sat-isfactory pumping.1 A pumpable concrete, like conventionalconcrete, requires good quality control, i.e., uniform, proper-ly graded aggregate, materials uniformly batched and mixedthoroughly.2 Concrete pumps are available with maximumoutput capacities ra

19、nging from 15 to 250 yd3/hr.Maximum volume output and maximum pressure on theconcrete cannot be achieved simultaneously from most con-crete pumps because this combination requires too muchpower. Each foot of vertical rise reduces the horizontalpumping distance about 3 to 4 ft because three to four t

20、imesmore pressure is required per foot of vertical rise than is nec-essary per foot of horizontal movement.Pumped concrete moves as a cylinder riding on a thin lu-bricant film of grout or mortar on the inside diameter of thepipeline.3-5 Before pumping begins, the pipeline interior di-ameter should b

21、e coated with grout. Depending on the natureof material used, this initial pipeline coating mixture may ormay not be used in the concrete placement. Once concreteflow through the pipeline is established, the lubrication willbe maintained as long as pumping continues with a properlyproportioned and c

22、onsistent mixture.CHAPTER 2PUMPING EQUIPMENT2.1Piston pumpsThe most common concrete pumps consist of a receivinghopper, two concrete pumping cylinders, and a valving sys-tem to alternately direct the flow of concrete into the pump-ing cylinders and from them to the pipeline (Fig. 1). Oneconcrete cyl

23、inder receives concrete from the receiving hop-per while the other discharges into the pipeline to provide arelatively constant flow of concrete through the pipeline tothe placing area. Pistons in the concrete cylinders create avacuum to draw in concrete on the intake stroke and mechan-ically push i

24、t into the pipeline on the discharge stroke. Thesepistons are driven by hydraulic cylinders on most pumps, butmay be driven mechanically. Primary power is provided bydiesel, gasoline, or electric motors. The cost of concretepumps and their maximum pumping capacity and pressureapplied to the concrete

25、 vary greatly. Components are sized toprovide the desired output, volume, and pressure on the con-crete in the pipeline. The hydraulic pumps on most units areequipped with horsepower limiters that protect the powerunit by destroking or reducing displacement to reduce thevolume output of the hydrauli

26、c pump so it can provide thepressure required to move concrete at the maximum heightor distance of the concrete pumps capability. Receiving hop-pers vary in size to match the volume capacity of the pumpand are usually equipped with agitators which prevent aggre-gate segregation and stacking in the h

27、opper. The hopper de-PLACING CONCRETE BY PUMPING METHODS 304.2R-3sign should maintain a head of concrete at the intake to theconcrete cylinders.2.2Types of valves2.2.1 Hydraulically powered valvesPumps in this classuse different types of valves, but all of them are operated hy-draulically and have t

28、he ability to crush or displace aggre-gate which becomes trapped in the valve area. The size of themaximum size aggregate (MSA) which can be pumped bythese units is controlled by the diameter of the concrete pas-sages within the pump and the diameter of the pipeline intowhich concrete is being pumpe

29、d (see Section 4.2.1). Most ofthese pumps have an outlet port 5 in. or larger in diameterand utilize reducers to reach smaller pipeline size as is nec-essary. Fig. 1 is typical of these units.The capacity of these pumps may vary from 20 to 250 yd3/hr. They handle the broadest possible range of concr

30、ete mix-tures that can be pumped.2.2.2 Ball-check concrete pumpsThis type of pump uti-lizes steel balls and mating seats to control the flow of con-crete from the hopper into the pumping cylinder and out ofthe pumping cylinder into the pipeline. The ball is forced intoits seat by the concrete being

31、pumped and has a very limitedability to displace or break aggregate which may be trappedin the valve area. Failure of the ball to seat results in loss ofpumping efficiency (Fig. 2). These units are limited topumping concrete with smaller than 1/2 in. MSA. The con-crete pistons in these units are fre

32、quently mechanically driv-en although there are hydraulically powered units available.They are usually rated at 20 yd3/hr or less. Because they areFig. 2Ball check pump schematicFig. 3Ball check concrete pump304.2R-4 ACI COMMITTEE REPORTlimited to small aggregate and low volume, they are fre-quently

33、 used for grouting and may pump through pipeline orhose as small as 2 in. in diameter (Fig. 3).2.3Trailer pumps2.3.1 GeneralTrailer-mounted pumps are available witha very wide range of capacities and pressures. These units areusually rated for maximum theoretical volume in yd3/hrbased on the diamete

34、r of the concrete cylinders and thelength and frequency of the pumping strokes and the pres-sure applied to the concrete at the piston face. The most sig-nificant comparison factor is the horsepower available topump concrete. The effect of horsepower limiters mentionedin Section 2.1 is most pronounc

35、ed on general purpose andmedium-duty trailer-mounted pumps because they use lowerhorsepower engines. Most trailer pumps are powered withdiesel engines and fall into relatively standard horsepowerranges that are determined by the number of cylinders in thepower unit and whether it is turbo-charged.2.

36、3.2 Small general purpose pumpsThese trailer-mount-ed pumps are generally rated from about 20 to 35 yd3/hr, arepowered with up to 60 hp engines, and weigh up to 5000 lb.They may have either hydraulically powered or ball-checkvalves. They generally utilize 5- and 6-in.-diameter concretecylinders and

37、apply pressures up to about 750 psi on the con-crete. They are capable of pumping up to 250 ft vertically orup to 1000 ft horizontally. They are most suitable for grout-ing masonry walls and placing concrete in floor slabs, foot-ings, walls, columns, and decks where the limitationsimposed by forming

38、 or finishing requirements limit the vol-ume of concrete and the rate at which it can be placed (Fig.4). Operators usually use the smallest possible pipeline di-ameter (Section 4.2.1) for the grout or concrete being pumped 2 in., 2 1/2 in., and 3 in. are the most popular sizes.2.3.3 Medium duty pump

39、sThese units have a capacityrange from about 40 to 80 yd3/hr, are powered with enginesfrom 60 to 110 hp, and weigh from 5000 to 10,000 lb. Theygenerally use 6-, 7-, or 8-in.-diameter concrete cylinders andare capable of applying pressures up to 900 psi on the con-crete. This pressure allows them to

40、pump up to 300 ft verti-cally or 1200 ft horizontally. They are used on larger volumeconcrete placements where the ability to place concrete morequickly justifies their higher cost of ownership and operation(Fig. 5). Operators generally use 4- or 5-in.-diameter pipe-lines.2.3.4 Special application p

41、umpsThese trailer-mountedpumps place over 80 yd3/hr, utilize engines with 110 hp andmore, and weigh over 10,000 lb. They have a wide variety ofpressure and volume capacities depending on the applica-tions for which they are used. Typical applications are spe-cialty projects like high-rise buildings

42、and tunnel projectsthat require pumping long horizontal distances because oflimited access (see Fig. 6). Pumps in this class have pumpedconcrete over 1400 ft vertically and over 4600 ft horizontal-ly. Pipeline is selected to match the volume and pressure re-quirements of the project (Chapter 3).2.4T

43、ruck-mounted concrete pumps2.4.1 Separate engine driveSeparate engine-driven con-crete pumps mounted on trucks are used primarily forprojects with capacity requirements where the horsepowerrequired for pumping the concrete is considerably less thanthat required to move the vehicle over the road. Suc

44、h pumpsare frequently modified versions of the general purpose trail-er pumps and have the same operating capacities.2.4.2 Truck engine-driven pumpsThese pumps have ca-pacities ranging from about 100 to 200 yd3/hr. They general-ly use 8- and 9-in.-diameter concrete cylinders and concretepressures ra

45、nge from about 640 to 1250 psi. Many units havedifferent ratings when pumping oil is applied to the rod side(high capacity) or to the piston side (high pressure) of the hy-draulic pumping cylinder. With such wide variations in ca-pacity, it is not possible to summarize maximum vertical andhorizontal

46、 pumping distances. These pumps are generallyused with placing booms and require a heavy-duty truckchassis to carry their combined weight. A larger engine is re-quired for highway travel than is normally required for thepumping operation. The most economical combination inthis case is to use the tru

47、ck engine and a split shaft or powerdivider that can use the truck engine to power the runninggear of the truck or to drive hydraulic pumps to providepumping power. These units have receiving hoppers muchlarger than those on most trailer pumps to accommodate theirhigher pumping rates (Fig. 7). High-

48、volume pumping re-quires that the receiving hopper have an effective agitator.2.5Placing boomsPlacing booms support a 5-in.-diameter pipeline which re-ceives the discharge from a concrete pump and places it inthe forms. Booms have three or four articulating sections.Fig. 4Pump with hydraulically pow

49、ered valvePLACING CONCRETE BY PUMPING METHODS 304.2R-5The booms are mounted on a turret that rotates to enable thedischarge of the pipeline to be located anywhere within a cir-cle. One type of boom telescopes 17 ft. Most booms are per-manently mounted to the trucks on which they aretransported, along with the concrete pump. Some booms aredesigned to be removed from the truck and mounted on apedestal that can be located in the placement area or support-ed on the floors of buildings under construction. There alsoare placing booms de