1、Designation: C 926 06Standard Specification forApplication of Portland Cement-Based Plaster1This standard is issued under the fixed designation C 926; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers the requirements for the appli-cation of full thickness portland cement-based plaster forexterior (stucco) and
3、 interior work.1.2 This specification sets forth tables for proportioning ofvarious plaster mixes and plaster thickness.NOTE 1General information will be found in Annex A1. Designconsiderations will be found in Annex A2.1.3 The values stated in inch-pound units are to be regardedas the standard. The
4、 SI (metric) values given in parentheses areapproximate and are provided for information purposes only.1.4 The text of this specification references notes andfootnotes that provide explanatory material. These notes andfootnotes (excluding those in tables and figures) shall not beconsidered as requir
5、ements of the specification.1.5 Details of construction for a specific assembly toachieve the required fire resistance shall be obtained fromreports of fire-resistance tests, engineering evaluations, orlistings from recognized fire testing laboratories.2. Referenced Documents2.1 ASTM Standards:2C11
6、Terminology Relating to Gypsum and Related Build-ing Materials and SystemsC25 Test Methods for Chemical Analysis of Limestone,Quicklime, and Hydrated LimeC35 Specification for Inorganic Aggregates for Use inGypsum PlasterC91 Specification for Masonry CementC 150 Specification for Portland CementC 20
7、6 Specification for Finishing Hydrated LimeC 207 Specification for Hydrated Lime for Masonry Pur-posesC 219 Terminology Relating to Hydraulic CementC 260 Specification for Air-Entraining Admixtures for Con-creteC 595 Specification for Blended Hydraulic CementsC 631 Specification for Bonding Compound
8、s for InteriorPlasteringC 897 Specification for Aggregate for Job-Mixed PortlandCement-Based PlastersC 932 Specification for Surface-Applied Bonding Agent forExterior PlasteringC 1063 Specification for Installation of Lathing and Furringto Receive Interior and Exterior Portland Cement-BasedPlasterC
9、1116 Specification for Fiber-Reinforced Concrete andShotcreteC 1328 Specification for Plastic (Stucco) CementE90 Test Method for Laboratory Measurement ofAirborne-Sound Transmission Loss of Building Partitionsand ElementsE119 Test Methods for Fire Tests of Building Constructionand MaterialsE 492 Tes
10、t Method for Laboratory Measurement of ImpactSound Transmission Through Floor-Ceiling AssembliesUsing the Tapping Machine2.2 ANSI Standard:A108.1 Specification for Installation of Ceramic Tile33. Terminology3.1 Terms shall be defined as in Terminologies C11 andC 219, except as modified herein.3.2 De
11、finitions of Terms Specific to This Standard:3.2.1 acceleratoran admixture that will shorten the set-ting time of plaster.3.2.2 admixturea material other than water, aggregate, orbasic cementitious material added to the batch before or duringjob mixing.1This specification is under the jurisdiction o
12、f ASTM Committee C11 onGypsum and Related Building Materials and Systems and is the direct responsibilityof Subcommittee C11.03 on Specifications for Application of Gypsum and OtherProducts on Assemblies.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1981. Last pre
13、vious edition approved in 2005 as C 92698a(2005).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available f
14、rom American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 acid etchingthe cl
15、eansing and controlled erosion ofa solid surface, using an acid wash.3.2.4 air entrainmentthe use of an air-entraining admix-ture or air-entraining cementitious material in a plaster mix toyield a controlled quantity of minute (typically between 10 and1000 m in diameter) disconnected air bubbles in
16、the plaster(see entrapped air).3.2.5 backplasterplaster applied to the face of metal lathopposite a previously applied plaster.3.2.6 bondthe state of adhesion between plaster coats orbetween plaster and plaster base.3.2.7 bonding compound or agentcompounds surface ap-plied or integrally mixed with p
17、laster to improve the quality ofbond between plaster and plaster base or between plaster coats.3.2.8 cementitious materiala material that, when mixedwith water and with or without aggregate, provides theplasticity and the cohesive and adhesive properties necessaryfor placement and the formation of a
18、 rigid mass.3.2.9 coata thickness of plaster applied in a single opera-tion.3.2.9.1 basecoatall plaster applied before the applicationof the finish coat.3.2.9.2 bedding coata plaster coat that receives aggregateor other decorative material impinged into its surface before itsets.3.2.9.3 brown coatin
19、 three-coat work, the second coat,applied over the scratch coat. In two-coat work, brown coatrefers to the double-up basecoat. In either use, the brown coatis the coat directly beneath the finish coat.3.2.9.4 dash-bond coata thick wet mixture of portlandcement and water, with or without aggregate, d
20、ashed onto thesurface of a plaster base such as smooth monolithic concrete orconcrete block surfaces to improve the mechanical key forsubsequent plaster coats.3.2.9.5 double-up coatthe brown-coat plaster applied tothe scratch coat plaster before the scratch-coat plaster has set.3.2.9.6 finish coatth
21、e final layer of plaster applied overbasecoat plaster.3.2.9.7 fog coata light coat of cement and water, with orwithout aggregate or color pigment, applied by machine sprayto improve color consistency.3.2.9.8 scratch coatthe first coat of plaster applied to aplaster base.3.2.9.9 skim coata thin finis
22、h coat applied to an existingplaster surface or other substrate to improve appearance.3.2.9.10 three-coat workapplication of plaster in threesuccessive coats with time between coats for setting or drying,or both.3.2.10 cold joint (“joining” or “jointing”)the juncture offresh plaster application adja
23、cent to set plaster, in the sameplane.3.2.11 curingthe act or processes of producing a moistureenvironment favorable to cement hydration, resulting in thesetting or hardening of the plaster.3.2.12 entrapped airunintentional air voids in the plastergenerally larger than 1 mm.3.2.13 factory prepared (
24、“mill-mixed” or “ready mixed”)pertaining to material combinations that have been formulatedand dry-blended by the manufacturer, requiring only theaddition of and mixing with water to produce plaster.3.2.14 fiber, natural or synthetican elongated fiber orstrand admixture added to plaster mix to impro
25、ve cohesivenessor pumpability, or both.3.2.15 floatingact of compacting and leveling brown-coatplaster to a reasonably true surface plane using a float tool orthe act of bringing the aggregate to the surface of finish-coatplaster.3.2.16 key (also mechanical key)plaster that physicallysurrounds, pene
26、trates, or deforms to lock onto the perforationsor irregularities of the plaster base or previous coat of plaster.3.2.17 metal plaster baseexpanded metal lath, or weldedor woven wire lath.3.2.18 plasterportland cement-based cementitious mix-ture (see stucco).3.2.19 requiredpertaining to a mandatory
27、obligation im-posed by a force outside of this specification, such as a buildingcode, project specification, contract, or purchase order.3.2.20 rustication (also “break”)an interruption orchange in plane of a plastered surface.3.2.21 scoring (also known as “scratching”)the groovingof the surface of
28、an unset plaster coat to provide a key for asubsequent coat.3.2.22 setthe chemical and physical change in plaster as itgoes from a plastic, workable state to a rigid state.3.2.23 stuccoportland cement-based plaster used on exte-rior locations.3.2.24 stucco finisha factory-prepared, dry blend of ma-t
29、erials for finish coat applications.3.2.25 temper, vto mix or restore unset plaster with waterto a workable consistency.3.2.26 textureany surface appearance as contrasted to asmooth surface.4. Materials4.1 Materials shall conform to the requirements of thereferenced specifications and standards and
30、to the requirementsspecified herein.4.2 Cement:4.2.1 Portland CementSpecification C 150, Type I, II, andIII, as specified. White where specified.4.2.2 Air-Entraining Portland CementSpecificationC 150, type as specified. White where specified.4.2.3 Masonry CementSpecification C91, Types N, S,and M. W
31、hite where specified.4.2.4 Blended Hydraulic CementSpecification C 595,Type IP, I(PM), IS, and I(SM) as specified.4.2.5 Air-Entraining Blended Hydraulic CementSpecification C 595, Type IP-A, I(PM)-A, IS-A, and I(SM)-Aas specified.4.2.6 Plastic CementPlastic Cement shall meet the re-quirements of Spe
32、cification C 1328, Standard Specification forPlastic (Stucco) Cement.NOTE 2Plastic cements are not available nationally.C9260624.3 Type “S” Hydrated LimeA hydrated lime that con-tains not more than 8 % unhydrated oxides when tested inaccordance with Test Methods C25. See Specifications C 206and C 20
33、7 for a complete description of a Type “S” hydratedlime.4.4 Aggregates:4.4.1 Sand for Base CoatsSpecification C 897. Aggregatefailing to meet gradation limits in Specification C 897 shall bepermitted to be used, provided the plaster made with this sandhas an acceptable demonstrated performance recor
34、d in similarconstruction and climate conditions.4.4.2 PerliteSpecification C35.4.4.3 Sand for Job-Mixed Finish CoatsSpecificationC 897.4.5 WaterWater used in mixing, application, and finishingof plaster shall be clean, fresh, suitable for domestic waterconsumption, and free of such amounts of minera
35、l or organicsubstances as would affect the set, the plaster, or any metal inthe system.4.6 AdmixturesSee 3.2.2 and .4.7 FibersSpecification C 1116 on alkali-resistant fibers,glass fibers, nylon, polypropylene or carbon fibers.5. Requirements for Bases to Receive Portland Cement-Based Plaster5.1 Meta
36、l bases and accessories used to receive plaster shallbe installed in conformance with Specification C 1063, exceptas otherwise specified.NOTE 3All metal, or PVC, or CPVC plastic members should be freeof deleterious amounts of rust, oil, or other foreign matter, which couldcause bond failure or unsig
37、htly discoloration.5.2 Surfaces of solid bases to receive plaster, such asmasonry, stone, cast-in-place or precast concrete shall bestraight and true within14 in. in 10 ft (2.1 mm/m) and shall befree of form oil or other elements, which would interfere withbonding. Form ties or other obstructions sh
38、all be removed ortrimmed back even with the surface of the solid base.5.2.1 Solid surfaces shall have the suction (ability to absorbwater) or surface roughness, or both, to provide the bondrequired for the plaster.5.2.2 Smooth or nonabsorbent solid surfaces, such as cast-in-place or precast concrete
39、, shall be prepared to receiveportland cement plaster by one of the following methods:5.2.2.1 Sandblasting, wire brushing, acid etching, or chip-ping or a combination thereof,5.2.2.2 Application of a dash-bond coat applied forcefullyagainst the surface, left untroweled, undisturbed, and moistcured f
40、or at least 24 h, or5.2.2.3 Application of a bonding compound suitable forexterior or interior exposure solid surfaces in accordance withthe manufacturers written directions.5.2.3 Where bond cannot be obtained over the entire surfaceto receive plaster by one or more of the methods in 5.2.2,orwhere t
41、otal plaster thickness will exceed the total thicknessspecified in Table 1 for types of solid bases, furred orself-furring metal plaster base shall be installed in accordancewith Specification C 1063.6. Plaster Proportions and Mixing6.1 Proportions:6.1.1 All portland cement plasters shall be mixed a
42、ndproportioned in accordance with the following tables andaccompanying requirements, using measuring devices ofknown volume with successive batches proportioned alike.6.1.2 Plaster mix used shall be as designated and referencedto Table 2.6.1.3 Base-coat proportions shall be as shown in Table 3 forth
43、e mix specified from Table 2.6.1.3.1 Measurement of MaterialsThe method of measur-ing materials for the plaster shall be such that the specifiedproportions are controlled and accurately maintained. Theweights per cubic foot of the materials are considered to be asfollows:Material Weight, lb/ft3(kg/m
44、3)Portland cement 94 (1505)Blended cement Weight printed on bagMasonry or plastic cement Weight printed on bagHydrated Lime 40 (640)Lime Putty 80 (1280)Sand, Damp and Loose (6.1.3.2) 80 (1280) of dry sandTABLE 1 Nominal Plaster ThicknessAfor Three- and Two-Coat Work, in. (mm)BASEVertical Horizontal1
45、st Coat 2nd Coat 3rd CoatBTotal 1st Coat 2nd Coat 3rd CoatBTotalInterior/ExteriorThree-coat work:CMetal plaster base38 (9.5)38 (9.5)18 (3)78 (22)14 (6)14 (6)18 (3)58 (16)Solid plaster base:Unit masonry14 (6)14 (6)18 (3)58 (16) Use two-coat workCast-in-place or precastconcrete14 (6)14 (6)18 (3)58 (16
46、)38 (9.5), maxMetal plaster base over solidbase12 (12.5)14 (6)18 (3)78 (22)12 (12.5)14 (6)18 (3)78 (22)Two-coat work:Solid plaster base:Unit masonry38 (9.5)18 (3)12 (12.5)38 (9.5)Cast-in-place or pre-castconcrete14 (6)18 (3)38 (9.5)38 (9.5)AExclusive of texture.BFor solid plaster partitions, additio
47、nal coats shall be applied to meet the finished thickness specified.CFor exposed aggregate finishes, the second (brown) coat shall become the “bedding” coat and shall be of sufficient thickness to receive and hold the aggregate.C9260636.1.3.2 For purposes of this specification, a weight of 80 lb(128
48、0 kg) of oven-dried sand shall be used. This is, in mostcases, equivalent to one cubic foot of loose, damp sand.6.1.4 Finish-coat proportions for job-mixed finish coatsshall be as specified in Table 4.6.1.5 Factory-Prepared Finish CoatsSee 3.2.14.6.1.6 Dash-bond coat proportions shall be 1 volume pa
49、rtportland cement and not more than 2 volume parts of aggregatemixed to a consistency that will permit application as specifiedin 7.1.5.6.1.7 Admixtures shall be proportioned, mixed, and appliedin accordance with the printed directions of the manufacturer.(See A2.5.)6.2 Mixing:6.2.1 All plaster shall be prepared in a mechanical mixer,using sufficient water to produce a workable consistency anduniform color. (See X1.1.)6.2.2 Base-coat plasters that have stiffened because ofevaporation of water sha
