ACI 229R-2013 Report on Controlled Low-Strength Materials.pdf

1、ACI 229R-13Report on Controlled Low-Strength MaterialsReported by ACI Committee 229First PrintingJune 2013Report on Controlled Low-Strength Materials Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or copied, in whole or pa

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10、 documents are available in print, by download, on CD-ROM, through electronic subscription, or reprint and may be obtained by contacting ACI.Most ACI standards and committee reports are gathered together in the annually revised ACI Manual of Concrete Practice (MCP).American Concrete Institute38800 C

11、ountry Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgISBN-13: 978-0-87031-816-0ISBN: 0-87031-816-0American Concrete InstituteAdvancing concrete knowledgeKeywords: aggregates; backfill; compacted fill; controlled density fill; controlled low-strength ma

12、terial; flowable fill; flowable mortar; fly ash; foundation stabilization; low-density material; pipe bedding; plastic soil-cement; preformed foam; soil-cement slurry; trench backfill; unshrinkable fill; void filling.ContentsCHAPteR 1IntRoDUCtIon, p. 2CHAPteR 2notAtIon AnD DeFInItIons, p. 22.1Notati

13、on, p. 22.2Definitions, p. 2CHAPteR 3APPLICAtIons, p. 23.1General, p. 23.2Backfills, p. 23.3Structural fills, p. 33.4Insulating and isolation fills, p. 43.5Thermal-insulation-conductivity fills, p. 43.6Pavement bases, p. 43.7Conduit bedding, p. 43.8Erosion control, p. 53.9Void filling, p. 53.10Nucle

14、ar facilities, p. 53.11Bridge reclamation, p. 6CHAPteR 4MAteRIALs, p. 64.1General, p. 64.2Portland cement, p. 64.3Fly ash, p. 64.4Admixtures, p. 64.5Mineral admixtures and other additives, p. 64.6Water, p. 64.7Aggregates, p. 64.8Nonstandard materials, p. 74.9Ponded ash or basin ash, p. 7CHAPteR 5PRo

15、PeRtIes, p. 75.1Introduction, p. 75.2Plastic properties, p. 75.3In-service properties, p. 9CHAPteR 6PRoPoRtIonInG, p. 116.1Introduction, p. 116.2Materials, p. 116.3General formulation, p. 116.4Proportioning methods, p. 116.5Evaluation, p. 126.6Adjustments to proportioning, p. 12CHAPteR 7MIXInG, tRAn

16、sPoRtInG, AnD PLACInG, p. 127.1General, p. 12ACI 229R-13Report on Controlled Low-strength MaterialsReported by ACI Committee 229Thomas A. Fox, Chair Charles E. Pierce, SecretaryWayne S. AdaskaJoseph A. AmonPaul D. BrooksTimothy S. FolksDean M. GoldenBrian H. GreenMorris HuffmanFrank A. KozeliskiRudo

17、lph N. KrausLeo A. LegatskiFrances A. McNeal-PageTarun R. NaikBruce W. RammeMichael D. SerraVictor H. SmithOrville R. Werner IIPeter T. YenConsulting membersKurt R. GrabowBradley M. KluteElizabeth OlenbushHarry C. Roof1ACI Committee Reports, Guides, and Commentaries are intended for guidance in plan

18、ning, 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 contains. The Amer

19、ican 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 Architect/Engineer

20、 to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer.ACI 229R-13 supersedes ACI 229R-99 and was adopted and published June 2013Copyright 2013, American Concrete InstituteAll rights reserved including rights of reproduction

21、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 reproduc-tion or for use in any knowledge or retrieval system or device, unless permission in writing is obtain

22、ed from the copyright proprietors.7.2Mixing, p. 127.3Transporting, p. 137.4Placing, p. 137.5Cautions, p. 13CHAPteR 8QUALItY ContRoL, p. 138.1General, p. 138.2Sampling of CLSM, p. 148.3Consistency and unit weight, p. 148.4Strength tests, p. 14CHAPteR 9LoW-DensItY CLsM UsInG PReFoRMeD FoAM, p. 149.1Ge

23、neral, p. 149.2Applications, p. 159.3Materials, p. 169.4Physical properties, p. 179.5Proportioning, p. 189.6Construction, p. 189.7Quality control, p. 19CHAPteR 10ReFeRenCes, p. 19CHAPteR 1IntRoDUCtIonControlled low-strength material (CLSM) is a self-consol-idating cementitious material used primaril

24、y as a backfill as an alternative to compacted fill. Terms used to describe this material include flowable fill, controlled density fill, flow-able mortar, plastic soil-cement, and soil-cement slurry.CLSM is a mixture intended to result in a compressive strength of 1200 psi (8.3 MPa) or less. Most C

25、LSM applica-tions require unconfined compressive strengths of 300 psi (2.1 MPa) or less. Long-term strengths (90 to 180 days) should be targeted to be less than 100 psi (0.7 MPa) for excavation with hand tools. Lower-strength requirements are necessary to allow for future excavation of CLSM.The term

26、 “CLSM” is used to describe a family of mixtures for various applications. CLSM mixtures can also be devel-oped as anticorrosion fills, electrically conductive materials, low-permeability fills, thermal fills, and durable pavement bases. For example, the upper limit of 1200 psi (8.3 MPa) allows use

27、of this material for applications where future excavation is unlikely, such as structural fill under build-ings. CLSM is a self-consolidated backfill or fill material that is used in place of compacted earth fill and should not be considered as a type of low-strength concrete. Gener-ally, CLSM mixtu

28、res are not designed to resist freezing and thawing, abrasive or erosive forces, or aggressive chemicals. Using recycled materials can maximize recycled material content for sustainable construction. Nonstandard materials that have been tested and found to satisfy the intended appli-cation can be us

29、ed to produce CLSM. Chapter 9 describes low-density (LD) CLSM produced using preformed foam as part of the mixture proportioning. Using preformed foam in LD-CLSM mixtures allows these materials to be produced having unit weights lower than those of typical CLSM. The distinctive properties of LD-CLSM

30、 and procedures for mixing it are discussed in Chapter 9.CLSM typically requires no consolidation or special curing procedures to achieve desired strength and should not be confused with compacted soil-cement, as reported in ACI 230.1R. Long-term compressive strengths for compacted soil-cement often

31、 exceed the 1200 psi (8.3 MPa) maximum limit established for CLSM.Long-term compressive strengths of 50 to 300 psi (0.3 to 2.1 MPa) are low when compared with conventional concrete. In terms of allowable bearing pressure, howeverwhich is a common criterion for measuring the capacity of a soil to sup

32、port a load50 to 100 psi (0.3 to 0.7 MPa) strength is equivalent to a well-compacted fill.Although CLSM generally costs more per cubic yard (cubic meter) than most soil or granular backfill materials, its many advantages often result in lower in-place costs. In fact, for some applications, CLSM is t

33、he only reasonable backfill method available (Adaska 1994, 1997; Ramme 1997). Table 1 lists a number of advantages to using CLSM (Smith 1991).CHAPteR 2notAtIon AnD DeFInItIons2.1notationE = modulus of elasticity, psi (MPa)fc = 28-day specified compressive strength of concrete, psi (kPa)k = coefficie

34、nt of permeability, in./s (mm/s)RE = removability modulusW = dry mass density, lb/ft3(kg/m3)2.2DefinitionsACI provides a comprehensive list of definitions through an online resource, “ACI Concrete Terminology,” http:/terminology.concrete.org.CHAPteR 3APPLICAtIons3.1GeneralThe primary application of

35、CLSM is as a structural fill or backfill in place of compacted soil. Because CLSM needs minimal consolidation and can be designed to be fluid, it is useful in areas where placing and compacting fill is difficult. If future excavation is anticipated, the maximum long-term compressive strength should

36、generally not exceed 100 psi (0.7 MPa). The following applications present a range of uses for CLSM (Sullivan 1997).3.2BackfillsCLSM can be readily placed into a trench, hole, or other cavity (Fig. 3.2a and 3.2b). Compaction or consolidation equipment is not required; hence, trench width or excava-t

37、ion size can be reduced. Granular or site-excavated back-fill, even if compacted or consolidated in the required layer thickness, cannot achieve the uniformity and density of CLSM (Sullivan 1997).When backfilling against retaining walls, consideration should be given to lateral pressures exerted on

38、the wall by flowable CLSM. Where lateral fluid pressure is a concern, American Concrete Institute Copyrighted Materialwww.concrete.org2 RePoRt on ContRoLLeD LoW-stRenGtH MAteRIALs (ACI 229R-13)CLSM can be placed in layers. This allows each layer to harden before placing the next layer.Following seve

39、re settlement problems of soil backfill in utility trenches, the city of Peoria, IL, in 1988, tried CLSM as backfill material (Smith 1991). CLSM was placed in trenches up to 9 ft (2.7 m) deep. Although fluid at time of placement, the CLSM hardened so that a persons weight could be supported within 2

40、 to 3 hours. Very few shrinkage cracks were observed. Further tests were conducted on patching the overlying pavement within 3 to 4 hours. In one test, a pavement patch was successfully placed over a sewer trench immediately after backfilling with CLSM. As a result of these initial tests, Peoria has

41、 changed its back-filling procedure to require using CLSM on all street open-ings (Smith 1991).Some agencies backfill with CLSM that has a setting time of 20 to 35 minutes, after which time, a person can walk on it. After approximately 1 hour, the wearing surface consisting of either a rapid-setting

42、 concrete or asphalt pave-ment is placed, and the result is a total traffic-bearing repair in approximately 4 hours (Pons et al. 1998).3.3structural fillsDepending on strength requirements, CLSM can be used for foundation support. Compressive strengths can vary from 100 to 1200 psi (0.7 to 8.3 MPa),

43、 depending on appli-cation. Where lightweight structural fills are required to reduce long-term settlement, a foaming agent may be used to provide lower unit weight. In weak soils, it can distribute the structures load over a greater area. For uneven or non-uniform subgrades under foundation footing

44、s and slabs, CLSM can provide a uniform and level surface. Compressive strengths vary depending on project requirements. Because table 1Cited advantages of CLsM (smith 1991)Readily availableUsing locally available materials, ready mixed concrete suppliers can produce CLSM to meet most project specif

45、ications.Easy to deliver Truck mixers can deliver specified quantities of CLSM to job site whenever material is needed.Easy to placeDepending on type and location of void to be filled, CLSM can be placed by chute, conveyor, pump, or bucket. Because CLSM is generally self-leveling, it needs little or

46、 no spreading or compacting. This speeds construction and reduces labor requirements.VersatileCLSM mixtures can be adjusted to meet specific fill requirements. Mixtures can be adjusted to improve flowability. More cement or fly ash can be added to increase strength. Admixtures can be added to adjust

47、 setting times and other performance characteristics. Adding foaming agents to CLSM produces light-weight, insulating fill.Strong and durableLoad-carrying capacities of CLSM are typically higher than those of compacted soil or granular fill. CLSM is also less permeable and is thus more resistant to

48、erosion. For use as permanent structural fill, CLSM can be designed to achieve 28-day compressive strength as high as 8.3 MPa (1200 psi).Allows fast return to trafficBecause many CLSMs can be placed quickly and support traffic loads within several hours, downtime for pavement repairs is minimal.Will

49、 not settleCLSM does not form voids during placement and will not settle or rut under loading. This advantage is especially significant if backfill is to be covered by pavement patch. Soil or granular fill, if not compacted properly, may settle after a pavement patch is placed and forms cracks or dips in the road.Reduces excavation costsCLSM allows narrower trenches because it eliminates having to widen trenches to accommodate consoli-dation equipment.Improves worker safety Workers can place CLSM in a trench without en