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

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1、ACI 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 any means, including the making of copies by any photo process, or by electronic or mechanical devi

2、ce, printed, written, or oral, or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.523.1R-1 ACI Committee Reports, Guides, Standard Practices, and Commentaries are intended fo

3、r 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 application of the material it

4、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 document are desired by the

5、 Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer. Guide for Cast-in-Place Low-Density Cellular Concrete Reported by ACI Committee 523 ACI 523.1R-06 This guide provides information on the materials, pr

6、operties, design, proper handling, and applications of cast-in-place low-density cellular concretes having oven-dry densities of 50 lb/ft 3(800 kg/m 3 ) or less. Roof deck systems and geotechnical applications often incorporate these low- density cellular concretes. Keywords: cellular concrete; engi

7、neered fill; foaming agent; geotechnical fill; insulating concrete; insulating concrete roof decks; low-density cellular concrete; low-density controlled low-strength material (LD-CLSM); preformed foam. CONTENTS Chapter 1General, p. 523.1R-2 1.1Definition of cellular concrete 1.2Definition of low-de

8、nsity, controlled low-strength material (LD-CLSM) Chapter 2Materials, p. 523.1R-2 2.1Cement 2.2Water 2.3Preformed foam 2.4Aggregates 2.5Admixtures 2.6Nonstandard materials 2.7Fiber reinforcement Chapter 3Physical properties, p. 523.1R-4 3.1As-cast density 3.2Oven-dry density 3.3Compressive strength

9、3.4Drying shrinkage 3.5Thermal expansion 3.6Walkability 3.7Mechanical attachment 3.8Thermal conductivity 3.9Fire resistance 3.10Permeability 3.11Freezing-and-thawing resistance Chapter 4Proportioning and testing, p. 523.1R-6 4.1Proportioning 4.2Ingredient compatibility 4.3Cast density 4.4Physical pr

10、operties Chapter 5Batching, mixing, placing, finishing, and curing, p. 523.1R-7 5.1Storage of materials 5.2Batching 5.3Mixing 5.4Placing 5.5Finishing 5.6Curing 5.7Placement in cold-weather conditions 5.8Placement in hot-weather conditions Chapter 6Design considerations for roof decks, p. 523.1R-8 6.

11、1Form systems Felipe Babbitt Wenyi Hu Frances A. McNeal-Page Konstantin Sobolev Bill T. Dye Keith Itzler Ali M. Memari Jennifer E. Tanner Fouad H. Fouad Richard E. Klingner Edgar Nunez Peter T. Yen Dean M. Golden Leo A. Legatski Caijun Shi Ronald F. Zollo Werner H. Gumpertz Daniel L. Liotti Edward M

12、. “Ned” Glysson Chair Ronald E. Barnett Secretary523.1R-2 ACI COMMITTEE REPORT 6.2Roofing readiness 6.3Load-carrying capacity 6.4Expansion and contraction joints 6.5Relief of vapor pressure 6.6Standard roofing details Chapter 7Geotechnical applications, p. 523.1R-10 7.1Backfill 7.2Roadway bases 7.3P

13、ipeline and culvert fills 7.4Void fills 7.5Tank fills 7.6Insulation and isolation fills Chapter 8References, p. 523.1R-12 8.1Referenced standards and reports 8.2Cited references CHAPTER 1GENERAL 1.1Definition of cellular concrete Low-density cellular concrete (Fig. 1.1) is defined as concrete made w

14、ith hydraulic cement, water, and preformed foam to form a hardened material having an oven-dry density of 50 lb/ft 3(800 kg/m 3 ) or less. These mixtures may include aggregate and other material components including, but not limited to, fly ash and chemical admixtures. This guide provides data and t

15、echniques pertaining to the properties and applications of cast-in-place low-density cellular concrete. Common applications of cast-in-place low-density cellular concrete are on roof decks and geotechnical applications. On roof decks, the material provides roofing base, thermal insulation, and drain

16、age slope for flat-roofed industrial and commercial buildings (Fig. 1.2). In geotechnical applications, the material is applied in thick sections of cellular concrete with low compressive strengths (Fig. 1.3) for the replacement of poor soils, fills for abandoned structures (pipelines), and cellular

17、 concrete fills designed, mixed, and placed to meet specific job conditions and functional requirements. 1.2Definition of low-density, controlled low-strength material (LD-CLSM) Controlled low-strength material (CLSM) is a cementitious material that is in a flowable state at the time of placement, a

18、nd that has a specified compressive strength of 1200 psi (8.3 MPa) or less at the age of 28 days. This material is discussed further in ACI 229R. Low-density CLSM (LD- CLSM) meets this definition, and has a cast density that is controllable from 20 to 50 lb/ft 3(320 to 800 kg/m 3 ). The quantity of

19、preformed foam in the mixture determines the mixtures final density. CHAPTER 2MATERIALS The basic materials in low-density cellular concrete are cement, water, and preformed foam. Because the main ingredient by volume of a low-density cellular concrete mixture is preformed foam, it is critical that

20、all admixtures be compatible with the preformed foam within the specific mixture. Trial mixture tests are needed to determine compatibility and the resulting physical properties. Low- density cellular concrete mixtures may also include supplementary cementitious materials. 2.1Cement The cement shoul

21、d meet the requirements of ASTM C 150 (portland cement), C 595 (blended cement), or C 1157 (hydraulic cement). Blended cements include cement containing combinations of portland cement, pozzolans, slag, other hydraulic cement, or some combination of these. Blended cement may result in lower rates of

22、 early strength Fig. 1.1Typical cell structure of cellular concrete. Fig. 1.2Roof deck application (click on picture to view video). Fig. 1.3Geotechnical application (click on picture to view video).CAST-IN-PLACE LOW-DENSITY CELLULAR CONCRETE 523.1R-3 development and should be tested for specific ap

23、plications. High-early-strength (Type III or HE) cement produces cellular concrete with higher rates of early strength development. 2.2Water Mixing water for concrete should be clean and free from detrimental amounts of oils, acids, alkalis, salts, organic materials, or other substances deleterious

24、to concrete or reinforcement. Any nonpotable water should be tested for hardness, pH, suspended solids, total salt content, and other characteristics that might affect the preformed foam, the setting time, and the strength of the low-density cellular concrete. 2.3Preformed foam Preformed foam is cre

25、ated by diluting a liquid foam concentrate with water in predetermined proportions (Fig. 2.1) and passing this mixture through a foam generator. Meter the preformed foam directly into the cement-water slurry at the job site (Fig. 2.2). The density of the preformed foam is typically between 2.5 and 4

26、.0 lb/ft 3 (40 and 65 kg/m 3 ). The foam concentrate should have a chemical composition capable of producing and maintaining stable air cells within the concrete mixture. The air cells should be able to resist the physical and chemical forces imposed during mixing, pumping, placing, and setting of t

27、he cellular concrete. If the cellular (air-cell) structure is not stable, it may break down under these forces, resulting in an increased concrete density. Most common proprietary formulations of foam concentrates contain protein hydrozylates or synthetic surfactants. ASTM C 796 provides a standard

28、method for laboratory measurement of the performance of a foaming chemical to be used in producing foam (air cells) for making cellular concrete. ASTM C 869 is a standard specification that covers foaming agents specifically formulated for making preformed foam for use in the production of cellular

29、concrete. This specification provides the means for evaluating the performance of a specific foaming agent. Further information concerning these formulations and the procedures for using them is available from foam manufacturers. 2.4Aggregates Low-density cellular concrete may include lightweight ag

30、gregates such as vermiculite or perlite meeting the require- ments of ASTM C 332 Group 1 to lower the slump to achieve steeper roof slopes, and to maintain moisture in dry climates. Wilson (1981) provides additional information on the use of lightweight aggregates used in cellular concrete. Any prop

31、osed aggregates should be tested for physical properties, pumpability, and compatibility in trial mixtures. 2.5Admixtures 2.5.1 Chemical admixturesChemical admixtures, such as water-reducing admixtures and set accelerators, are used with cellular concretes. Water-reducing admixtures can improve comp

32、ressive strength for special mixtures or applications. Hot water, high-early-strength (Type III or HE) cement, and chemical accelerators can be used singly or in combination to accelerate setting. Accelerators containing chloride ions should not be used in cellular concrete placed in contact with st

33、eel. Chemical admixtures should conform to ASTM C 494 and be used at dosages recommended by the manufacturer or determined by trial mixtures. Not all chemical admixtures are compatible for use in foamed cellular concrete. Individual manufacturers of foam concentrate should be contacted for informati

34、on about the compatibility of specific admixtures with their foam concentrates, and trial batches should be used to determine the resulting mixture characteristics. 2.5.2 Supplementary cementitious materialsIn the production of cellular concrete, supplementary cementitious materials such as fly ash,

35、 silica fume, high reactivity metakaolin, or ground-granulated blast-furnace slag (slag cement) are included to reduce bleeding and segregation and to increase strength. Trial batches should be used to confirm the compatibility of the selected foam concentrate with other admixtures, and to help dete

36、rmine the proper admixture dosages and resulting physical properties. Various mineral admixtures may differ considerably in composition, fineness, and other properties. The user should review major fly ash propertiesloss on ignition (LOI), cementing activity, and Fig. 2.1Diluting foam concentrate in

37、 water (click on pic- ture to view video). Fig. 2.2Metering preformed foam into cement-water slurry (click on picture to view video).523.1R-4 ACI COMMITTEE REPORT water demand of the fly ashbefore including fly ash in a low-density cellular concrete mixture. The first of these properties (LOI) is ad

38、dressed in ASTM C 618. A fly ash with a high LOI (carbon content) may adversely affect the preformed foam by causing an increase in density and loss of yield. If cementing activity is low, the concrete may set too slowly, resulting in a lower strength and a higher density. High water demand may requ

39、ire that the water-cementitious material ratio (w/cm) be adjusted to achieve the desired strength. 2.6Nonstandard materials Special cements, supplementary cementitious materials, and aggregates may be included as nonstandard materials. Some mine-fill applications may use local materials as aggregate

40、s or fillers in low-density cellular concrete to extend the mixture when transportation of materials to remote areas is difficult. The user should pretest nonstandard mixtures for proper development of the desired fill properties. 2.7Fiber reinforcement Low-density cellular concrete may include comm

41、ercially available 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- ments. Cellular concretes flexural and tensile strength, impact resistance, fatigue limit, energy absorption,

42、and spalling resistance can be enhanced through the use of fibers that are known to be sufficiently durable under the expected service conditions. Zollo and Hays (1998) address the material and engineering properties of fiber-reinforced cellular concrete. Fibers can also help control plastic shrinka

43、ge cracking (Fig. 2.4). CHAPTER 3PHYSICAL PROPERTIES 3.1As-cast density The as-cast density at the point of placement should be determined by calculating the density of samples using a container of known volume and empty weight, as prescribed in applicable sections of ASTM C 796 (Fig. 3.1). Monitori

44、ng the as-cast density of the cellular concrete is an important job-site quality-assurance tool for controlling the uniformity and density of the mixture at the point of placement. Procedures for sampling and testing hardened insulating cellular concrete are given in ASTM C 513. 3.2Oven-dry density

45、Oven-dry density, evaluated using ASTM C 796 and C 495, determines the unit weight used to define low-density cellular concrete, which by definition has a maximum oven- dry density of 50 lb/ft 3(800 kg/m 3 ). 3.3Compressive strength The relationship between compressive strength and as-cast density i

46、s an important indicator of the quality of cellular concrete (Kearsley and Wainwright 2002b). The compressive strength of cellular concrete should be evaluated in accordance with ASTM C 796 and C 495. Compressive strength specimens should not be oven-dried. When it is necessary to determine oven-dry

47、 density, it is necessary to make companion specimens for this test in addition to those specimens for compressive strength testing. The user should relate compressive strength to the oven-dry density of cellular concrete as indicated in Table 3.1. Table 3.1 is a guideline only, based on Type I ceme

48、nt, no cement substitution, and using local materials. The user should test specific local materials to determine these properties. For geotechnical applications, the cast density of the material is usually the most significant property and is more important than bearing capacity (unconfined compres

49、sive Fig. 2.3Typical fiber types. Fig. 2.4Fibers in cellular concrete. Fig. 3.1Measuring as-cast density (click on picture to view video).CAST-IN-PLACE LOW-DENSITY CELLULAR CONCRETE 523.1R-5 strength). As a result, these densities and compressive strengths are lower than those for roof deck applications (Table 3.2). If standard materials are used, the density of the low-density cellular concrete has properties that fall within ranges specified by the manufacturer of the foam concentrate. If nonstandard materia