ACI 523.1R-2006 Guide for Cast-in-Place Low-Density Cellular Concrete《现场浇筑低密度蜂窝混凝土用指南》.pdf

1、I Committee 523Guide for Cast-in-Place LoCellular ConcreteReported by ACThis guide provides information on the materials, properties, design,proper handling, and applications of cast-in-place low-density cellularconcretes having oven-dry densities of 50 lb/ft3(800 kg/m3) or less. Roofdeck systems an

2、d geotechnical applications often incorporate these low-density cellular concretes.Keywords: cellular concrete; engineered fill; foaming agent; geotechnicalfill; insulating concrete; insulating concrete roof decks; low-density cellularconcrete; low-density controlled low-strength material (LD-CLSM);

3、preformed foam.CONTENTSChapter 1General, p. 523.1R-21.1Definition of cellular concrete1.2Definition of low-density, controlled low-strengthmaterial (LD-CLSM)Chapter 2Materials, p. 523.1R-2Felipe Babbitt Wenyi HuBill T. Dye Keith ItzlerFouad H. Fouad Richard E. KlingnerDean M. Golden Leo A. LegatskiW

4、erner H. Gumpertz Daniel L. LiottiEdward M. “Ned” GlyssonChair523.1R-1ACI Committee Reports, Guides, Standard Practices, andCommentaries are intended for guidance in planning,designing, executing, and inspecting construction. Thisdocument is intended for the use of individuals who arecompetent to ev

5、aluate the significance and limitations of itscontent and recommendations and who will acceptresponsibility for the application of the material it contains.The American Concrete Institute disclaims any and allresponsibility for the stated principles. The Institute shall notbe liable for any loss or

6、damage arising therefrom.Reference to this document shall not be made in contractdocuments. If items found in this document are desired by theArchitect/Engineer to be a part of the contract documents, theyshall be restated in mandatory language for incorporation bythe Architect/Engineer.2.1Cement2.2

7、Water2.3Preformed foam2.4Aggregates2.5Admixtures2.6Nonstandard materials2.7Fiber reinforcementw-DensityACI 523.1R-06Chapter 3Physical properties, p. 523.1R-43.1As-cast density 3.2Oven-dry density3.3Compressive strength3.4Drying shrinkage3.5Thermal expansion3.6Walkability3.7Mechanical attachment3.8Th

8、ermal conductivity3.9Fire resistance3.10Permeability3.11Freezing-and-thawing resistanceChapter 4Proportioning and testing, p. 523.1R-64.1Proportioning4.2Ingredient compatibility4.3Cast densityFrances A. McNeal-Page Konstantin SobolevAli M. Memari Jennifer E. TannerEdgar Nunez Peter T. YenCaijun Shi

9、Ronald F. ZolloRonald E. BarnettSecretaryACI 523.1R-06 supersedes ACI 523.1R-92 and became effective August 15, 2006.Copyright 2006, 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 proces

10、s, or by electronic ormechanical device, printed, written, or oral, or recording for sound or visual reproductionor for use in any knowledge or retrieval system or device, unless permission in writingis obtained from the copyright proprietors.4.4Physical propertiesChapter 5Batching, mixing, placing,

11、 finishing, and curing, p. 523.1R-75.1Storage of materials5.2Batching5.3Mixing5.4Placing5.5Finishing5.6Curing5.7Placement in cold-weather conditions5.8Placement in hot-weather conditionsChapter 6Design considerations for roof decks, p. 523.1R-86.1Form systemsthick sections of cellular concrete with

12、low compressivestrengths (Fig. 1.3) for the replacement of poor soils, fills forabandoned structures (pipelines), and cellular concrete fillsdesigned, mixed, and placed to meet specific job conditionsand functional requirements.1.2Definition of low-density, controlledlow-strength material (LD-CLSM)C

13、ontrolled low-strength material (CLSM) is a cementitiousmaterial that is in a flowable state at the time of placement,and that has a specified compressive strength of 1200 psi(8.3 MPa) or less at the age of 28 days. This material isdiscussed further in ACI 229R. Low-density CLSM (LD-CLSM) meets this

14、 definition, and has a cast density that iscontrollable from 20 to 50 lb/ft3(320 to 800 kg/m3). Thequantity of preformed foam in the mixture determines themixtures final density.CHAPTER 2MATERIALSThe basic materials in low-density cellular concrete arecement, water, and preformed foam. Because the m

15、ainingredient by volume of a low-density cellular concretemixture is preformed foam, it is critical that all admixtures becompatible with the preformed foam within the specificmixture. Trial mixture tests are needed to determinecompatibility and the resulting physical properties. Low-density cellula

16、r concrete mixtures may also includesupplementary cementitious materials.2.1CementThe cement should meet the requirements of ASTM C 150(portland cement), C 595 (blended cement), or C 1157(hydraulic cement). Blended cements include cementcontaining combinations of portland cement, pozzolans, slag,oth

17、er hydraulic cement, or some combination of these.Fig. 1.3Geotechnical application (click on picture to viewvideo).foam to form a hardened material having an oven-drydensity of 50 lb/ft3(800 kg/m3) or less. These mixtures mayinclude aggregate and other material components including,but not limited t

18、o, fly ash and chemical admixtures.This guide provides data and techniques pertaining to theproperties and applications of cast-in-place low-densitycellular concrete. Common applications of cast-in-placelow-density cellular concrete are on roof decks andgeotechnical applications. On roof decks, the

19、materialprovides roofing base, thermal insulation, and drainage slopefor flat-roofed industrial and commercial buildings (Fig. 1.2).In geotechnical applications, the material is applied invideo).1.1Definition of cellular concreteLow-density cellular concrete (Fig. 1.1) is defined asconcrete made wit

20、h hydraulic cement, water, and preformedFig. 1.1Typical cell structure of cellular concrete.Fig. 1.2Roof deck application (click on picture to view523.1R-2 ACI COMMITTEE REPORT6.2Roofing readiness6.3Load-carrying capacity6.4Expansion and contraction joints6.5Relief of vapor pressure6.6Standard roofi

21、ng detailsChapter 7Geotechnical applications,p. 523.1R-107.1Backfill7.2Roadway bases7.3Pipeline and culvert fills7.4Void fills7.5Tank fills7.6Insulation and isolation fillsChapter 8References, p. 523.1R-128.1Referenced standards and reports8.2Cited referencesCHAPTER 1GENERALBlended cement may result

22、 in lower rates of early strengthand other properties. The user should review major fly ashfor using them is available from foam manufacturers.2.4AggregatesLow-density cellular concrete may include lightweightaggregates such as vermiculite or perlite meeting the require-ments of ASTM C 332 Group 1 t

23、o lower the slump toachieve steeper roof slopes, and to maintain moisture in dryclimates. Wilson (1981) provides additional information onthe use of lightweight aggregates used in cellular concrete.Any proposed aggregates should be tested for physicalproperties, pumpability, and compatibility in tri

24、al mixtures.2.5Admixtures2.5.1 Chemical admixturesChemical admixtures, suchas water-reducing admixtures and set accelerators, are usedwith cellular concretes. Water-reducing admixtures can improvecompressive strength for special mixtures or applications.Hot water, high-early-strength (Type III or HE

25、) cement, andchemical accelerators can be used singly or in combinationand be used at dosages recommended by the manufacturer ordetermined by trial mixtures.Not all chemical admixtures are compatible for use infoamed cellular concrete. Individual manufacturers of foamconcentrate should be contacted

26、for information about thecompatibility of specific admixtures with their foamconcentrates, and trial batches should be used to determinethe resulting mixture characteristics.2.5.2 Supplementary cementitious materialsIn theproduction of cellular concrete, supplementary cementitiousmaterials such as f

27、ly ash, silica fume, high reactivitymetakaolin, or ground-granulated blast-furnace slag (slagcement) are included to reduce bleeding and segregation andto increase strength. Trial batches should be used to confirmthe compatibility of the selected foam concentrate with otheradmixtures, and to help de

28、termine the proper admixturedosages and resulting physical properties. Various mineraladmixtures may differ considerably in composition, fineness,concrete. This specification provides the means for evaluatingthe performance of a specific foaming agent. Furtherinformation concerning these formulation

29、s and the proceduresto accelerate setting. Accelerators containing chloride ionsshould not be used in cellular concrete placed in contact withsteel. Chemical admixtures should conform to ASTM C 494Fig. 2.2Metering preformed foam into cement-water slurry(click on picture to view video).CAST-IN-PLACE

30、LOW-DENSITY CELLULAR CONCRETEdevelopment and should be tested for specific applications.High-early-strength (Type III or HE) cement produces cellularconcrete with higher rates of early strength development.2.2WaterMixing water for concrete should be clean and free fromdetrimental amounts of oils, ac

31、ids, alkalis, salts, organicmaterials, or other substances deleterious to concrete orreinforcement. Any nonpotable water should be tested forhardness, pH, suspended solids, total salt content, andother characteristics that might affect the preformedfoam, the setting time, and the strength of the low

32、-densitycellular concrete.2.3Preformed foamPreformed foam is created by diluting a liquid foamconcentrate with water in predetermined proportions (Fig. 2.1)and passing this mixture through a foam generator. Meter thepreformed foam directly into the cement-water slurry at the jobsite (Fig. 2.2). The

33、density of the preformed foam is typicallybetween 2.5 and 4.0 lb/ft3 (40 and 65 kg/m3).The foam concentrate should have a chemical compositioncapable of producing and maintaining stable air cells withinthe concrete mixture. The air cells should be able to resist thephysical and chemical forces impos

34、ed during mixing,pumping, placing, and setting of the cellular concrete. If thecellular (air-cell) structure is not stable, it may break downunder these forces, resulting in an increased concretedensity. Most common proprietary formulations of foamconcentrates contain protein hydrozylates or synthet

35、icsurfactants. ASTM C 796 provides a standard method forlaboratory measurement of the performance of a foamingchemical to be used in producing foam (air cells) for makingcellular concrete. ASTM C 869 is a standard specificationthat covers foaming agents specifically formulated formaking preformed fo

36、am for use in the production of cellular523.1R-3Fig. 2.1Diluting foam concentrate in water (click on pic-ture to view video).propertiesloss on ignition (LOI), cementing activity, and523.1R-4 ACI COMMITTEE REPORTwater demand of the fly ashbefore including fly ash in alow-density cellular concrete mix

37、ture. The first of theseproperties (LOI) is addressed in ASTM C 618. A fly ash witha high LOI (carbon content) may adversely affect thepreformed foam by causing an increase in density and loss ofyield. If cementing activity is low, the concrete may set tooslowly, resulting in a lower strength and a

38、higher density. Highwater demand may require that the water-cementitious materialratio (w/cm) be adjusted to achieve the desired strength.2.6Nonstandard materialsSpecial cements, supplementary cementitious materials,and aggregates may be included as nonstandard materials.Some mine-fill applications

39、may use local materials asaggregates or fillers in low-density cellular concrete to extendthe mixture when transportation of materials to remote areas isdifficult. The user should pretest nonstandard mixtures forproper development of the desired fill properties.2.7Fiber reinforcementLow-density cell

40、ular concrete may include commerciallyavailable fibers, such as nylon, polypropylene, polyester,and alkali-resistant glass, as reinforcing materials (Fig. 2.3).The choice of fiber type depends on performance require-Fig. 2.3Typical fiber types.Fig. 2.4Fibers in cellular concrete.ments. Cellular conc

41、retes flexural and tensile strength,impact resistance, fatigue limit, energy absorption, andspalling resistance can be enhanced through the use of fibersthat are known to be sufficiently durable under the expectedservice conditions. Zollo and Hays (1998) address thematerial and engineering propertie

42、s of fiber-reinforcedcellular concrete. Fibers can also help control plasticshrinkage cracking (Fig. 2.4).CHAPTER 3PHYSICAL PROPERTIES3.1As-cast densityThe as-cast density at the point of placement should bedetermined by calculating the density of samples using acontainer of known volume and empty w

43、eight, as prescribedin applicable sections of ASTM C 796 (Fig. 3.1). Monitoringthe as-cast density of the cellular concrete is an importantjob-site quality-assurance tool for controlling the uniformityand density of the mixture at the point of placement. Proceduresfor sampling and testing hardened i

44、nsulating cellularconcrete are given in ASTM C 513.3.2Oven-dry densityOven-dry density, evaluated using ASTM C 796 and C 495,determines the unit weight used to define low-densitycellular concrete, which by definition has a maximum oven-dry density of 50 lb/ft3(800 kg/m3).3.3Compressive strengthThe r

45、elationship between compressive strength and as-castdensity is an important indicator of the quality of cellularconcrete (Kearsley and Wainwright 2002b). The compressivestrength of cellular concrete should be evaluated in accordancewith ASTM C 796 and C 495. Compressive strength specimensshould not

46、be oven-dried. When it is necessary to determineoven-dry density, it is necessary to make companion specimensfor this test in addition to those specimens for compressivestrength testing. The user should relate compressive strengthto the oven-dry density of cellular concrete as indicated inTable 3.1.

47、 Table 3.1 is a guideline only, based on Type Icement, no cement substitution, and using local materials.The user should test specific local materials to determinethese properties.For geotechnical applications, the cast density of thematerial is usually the most significant property and is moreFig.

48、3.1Measuring as-cast density (click on picture toview video).important than bearing capacity (unconfined compressiveand highway construction per ACI SP-29 (ACI Committees213 and 523 1971).3.4Drying shrinkageDrying shrinkage is not usually critical in cellular concreteused for roof deck insulation or

49、 geotechnical applications.The reason for this is that when cellular concrete is used toinsulate roof decks, it is not considered to contribute structur-ally; and when it is used in geotechnical applications, anyshrinkage cracking that it might undergo does not significantlyreduce bearing capacity. Drying shrinkage is typically0.30 to 0.60% after 6 months at 50% relative humidity and73 F (23 C), and increases with decreasing density. SomeCAST-IN-PLACE LOW-DENSITY CELLULAR CONCRETEstrength). As a result, the