1、Designation: C926 16C926 16aStandard Specification forApplication of Portland Cement-Based Plaster1This standard is issued under the fixed designation C926; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers the requirements for the application of full thickness portland cement-based plaster for exterior(stucco)
3、 and interior work.1.2 This specification sets forth tables for proportioning of various plaster mixes and plaster thickness.NOTE 1General information will be found in Annex A1. Design considerations will be found in Annex A2.1.3 The values stated in inch-pound units are to be regarded as the standa
4、rd. The SI (metric) values given in parentheses areapproximate and are provided for information purposes only.1.4 The text of this specification references notes and footnotes that provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be considered
5、as requirements of the specification.1.5 Details of construction for a specific assembly to achieve the required fire resistance shall be obtained from reports offire-resistance tests, engineering evaluations, or listings from recognized fire testing laboratories.2. Referenced Documents2.1 ASTM Stan
6、dards:2C11 Terminology Relating to Gypsum and Related Building Materials and SystemsC25 Test Methods for Chemical Analysis of Limestone, Quicklime, and Hydrated LimeC35 Specification for Inorganic Aggregates for Use in Gypsum PlasterC91 Specification for Masonry CementC150 Specification for Portland
7、 CementC206 Specification for Finishing Hydrated LimeC207 Specification for Hydrated Lime for Masonry PurposesC219 Terminology Relating to Hydraulic CementC260 Specification for Air-Entraining Admixtures for ConcreteC578 Specification for Rigid, Cellular Polystyrene Thermal InsulationC595 Specificat
8、ion for Blended Hydraulic CementsC631 Specification for Bonding Compounds for Interior Gypsum PlasteringC897 Specification for Aggregate for Job-Mixed Portland Cement-Based PlastersC932 Specification for Surface-Applied Bonding Compounds for Exterior PlasteringC1063 Specification for Installation of
9、 Lathing and Furring to Receive Interior and Exterior Portland Cement-Based PlasterC1116 Specification for Fiber-Reinforced Concrete and ShotcreteC1328 Specification for Plastic (Stucco) CementC1787 Specification for Installation of Non Metallic Plaster Bases (Lath) Used with Portland Cement Based P
10、laster in VerticalWall ApplicationsE90 Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and ElementsE119 Test Methods for Fire Tests of Building Construction and Materials1 This specification is under the jurisdiction of ASTM Committee C11 on Gypsum a
11、nd Related Building Materials and Systems and is the direct responsibility ofSubcommittee C11.03 on Specifications for the Application of Gypsum and Other Products in Assemblies.Current edition approved Jan. 1, 2016March 1, 2016. Published January 2016April 2016. Originally approved in 1981. Last pr
12、evious edition approved in 20152016 asC926 15bC926 16.1. DOI: 10.1520/C0926-16.10.1520/C0926-16A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Docume
13、nt Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM rec
14、ommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C
15、700, West Conshohocken, PA 19428-2959. United States1E492 Test Method for Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using theTapping Machine2.2 ANSI Standard:A108.1 Specification for Installation of Ceramic Tile33. Terminology3.1 Terms shall be defined as i
16、n Terminologies C11 and C219, except as modified herein.3.2 Definitions of Terms Specific to This Standard:3.2.1 accelerator, nan admixture that will shorten the setting time of plaster.3.2.2 admixture, na material other than water, aggregate, or basic cementitious material added to the batch before
17、 or duringjob mixing.3.2.3 acid etching, nthe cleansing and controlled erosion of a solid surface, using an acid wash.3.2.4 air entrainment, nthe use of an air-entraining admixture or air-entraining cementitious material in a plaster mix to yielda controlled quantity of minute (typically between 10
18、and 1000 m in diameter) disconnected air bubbles in the plaster (seeentrapped air).3.2.5 back wrap, na means of terminating a polymer-modified, fabric reinforced cementitious base coat by wrapping thereinforcing mesh, which has been affixed to the substrate onto the outboard surface of the foam plas
19、tic core to provide continuityof the reinforced base coat and protection for the foam plastic core.3.2.6 backplaster, nplaster applied to the face of metal lath opposite a previously applied plaster.3.2.7 barrier wall, ntype of wall system that is intended to block or interrupt the movement of water
20、 to the interior.3.2.8 bond, nthe state of adhesion between plaster coats or between plaster and plaster base.3.2.9 bonding compound or agent, ncompounds surface applied or integrally mixed with plaster to improve the quality ofbond between plaster and plaster base or between plaster coats.3.2.10 ce
21、mentitious material, na material that, when mixed with water and with or without aggregate, provides the plasticityand the cohesive and adhesive properties necessary for placement and the formation of a rigid mass.3.2.11 coat, na thickness of plaster applied in a single operation.3.2.11.1 basecoat,
22、nall plaster applied before the application of the finish coat.3.2.11.2 bedding coat, na plaster coat that receives aggregate or other decorative material impinged into its surface before itsets.3.2.11.3 brown coat, nin three-coat work, the second coat, applied over the scratch coat. In two-coat wor
23、k, brown coat refersto the double-up basecoat. In either use, the brown coat is the coat directly beneath the finish coat.3.2.11.4 dash-bond coat, na thick wet mixture of portland cement and water, with or without aggregate, dashed onto thesurface of a plaster base such as smooth monolithic concrete
24、 or concrete block surfaces to improve the mechanical key forsubsequent plaster coats.3.2.11.5 double-up coat, nthe brown-coat plaster applied to the scratch coat plaster before the scratch-coat plaster has set.3.2.11.6 finish coat, nthe final layer of plaster applied over basecoat plaster.3.2.11.7
25、fog coat, na light coat of cement and water, with or without aggregate or color pigment, applied by machine sprayto improve color consistency.3.2.11.8 scratch coat, nthe first coat of plaster applied to a plaster base.3.2.11.9 skim coat, na thin finish coat applied to an existing plaster surface or
26、other substrate to improve appearance.3.2.11.10 three-coat work, napplication of plaster in three successive coats with time between coats for setting or drying, orboth.3.2.12 cold joint (“joining” or “jointing”), nthe juncture of fresh plaster application adjacent to set plaster, in the same plane.
27、3.2.13 curing, vthe act or processes of producing a moisture environment favorable to cement hydration, resulting in thesetting or hardening of the plaster.3.2.14 drainage wall, na wall system in which the cladding provides a substantial barrier to water intrusion, and which alsoincorporates a conce
28、aled water-resistive barrier over which drainage will occur.3.2.15 entrapped air, nunintentional air voids in the plaster generally larger than 1 mm.3.2.16 factory prepared (“mill-mixed” or “ready mixed”), adjpertaining to material combinations that have been formulatedand dry-blended by the manufac
29、turer, requiring only the addition of and mixing with water to produce plaster.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.C926 16a23.2.17 fiber, natural or synthetic, nan elongated fiber or strand admixture added to plaster mix to imp
30、rove cohesiveness orpumpability, or both.3.2.18 floating, vact of compacting and leveling brown-coat plaster to a reasonably true surface plane using a float tool or theact of bringing the aggregate to the surface of finish-coat plaster.3.2.19 key (also mechanical key), nplaster that physically surr
31、ounds, penetrates, or deforms to lock onto the perforations orirregularities of the plaster base or previous coat of plaster.3.2.20 metal plaster base, nexpanded metal lath, or welded or woven wire lath.3.2.21 plaster, nportland cement-based cementitious mixture (see stucco).3.2.22 polymer modified
32、cementitious base coat, nAbase coat containing portland cement modified with chemical admixtures(typically polymer latexes) to improve characteristics of the finished product, such as workability, plasticity, water resistance, andadhesion.3.2.23 required, adjpertaining to a mandatory obligation impo
33、sed by a force outside of this specification, such as a buildingcode, project specification, contract, or purchase order.3.2.24 rustication (also “break”), nan interruption or change in plane of a plastered surface.3.2.25 scoring (also known as “scratching”), nthe grooving of the surface of an unset
34、 plaster coat to provide a key for asubsequent coat.3.2.26 set, nthe chemical and physical change in plaster as it goes from a plastic, workable state to a rigid state.3.2.27 solid plaster bases, nsubstrates that do not require a metal plaster base, including cast in place and precast concrete,concr
35、ete and stone masonry, clay brick, and tile.3.2.28 stucco, nportland cement-based plaster used on exterior locations.3.2.29 stucco finish, na factory-prepared, dry blend of materials for finish coat applications.3.2.30 temper, vto mix or restore unset plaster with water to a workable consistency.3.2
36、.31 texture, nany surface appearance as contrasted to a smooth surface.4. Delivery and Storage of Materials4.1 Delivery:4.1.1 Packaged materials shall be delivered in factory-sealed, unopened, and unbroken packages, containers, or bundles.4.1.2 Bulk materials shall be delivered in clean transport ve
37、ssels, free of contaminates.4.2 Storage:4.2.1 Weather-sensitive materials shall be kept in a dry condition until ready for use. (See A2.4.)4.2.2 Bulk materials shall be stored to prevent subsequent contamination and segregation.5. Materials5.1 Materials shall conform to the requirements of the refer
38、enced specifications and standards and to the requirements specifiedherein.5.2 Cement:5.2.1 Portland CementSpecification C150, Type I, II, and III, as specified. White where specified.5.2.2 Air-Entraining Portland CementSpecification C150, type as specified. White where specified.5.2.3 Masonry Cemen
39、tSpecification C91, Types N, S, and M. White where specified.5.2.4 Blended Hydraulic CementSpecification C595, Type IP, IS(70), IL, and IT(S70), as specified.5.2.5 Air-Entraining Blended Hydraulic CementSpecification C595, Type IP-(A), IS(70)-(A), IL-(A), and IT (S70)-(A), asspecified.5.2.6 Plastic
40、CementPlastic Cement shall meet the requirements of Specification C1328, Standard Specification for Plastic(Stucco) Cement.NOTE 2Plastic cements are not available nationally.5.3 Type “S” Hydrated LimeA hydrated lime that contains not more than 8 % unhydrated oxides when tested in accordancewith Test
41、 Methods C25. See Specifications C206 and C207 for a complete description of a Type “S” hydrated lime.5.4 Aggregates:5.4.1 Sand for Base CoatsSpecification C897. Aggregate failing to meet gradation limits in Specification C897 shall bepermitted to be used, provided the plaster made with this sand ha
42、s an acceptable demonstrated performance record in similarconstruction and climate conditions.5.4.2 PerliteSpecification C35.5.4.3 Sand for Job-Mixed Finish CoatsSpecification C897.C926 16a35.5 WaterWater used in mixing, application, and finishing of plaster shall be clean, fresh, suitable for domes
43、tic waterconsumption, and free of such amounts of mineral or organic substances as would affect the set, the plaster, or any metal in thesystem.5.6 AdmixturesSee 3.2.2 and A2.5.5.7 FibersSpecification C1116 on alkali-resistant fibers, glass fibers, nylon, polypropylene or carbon fibers.5.8 Product M
44、arkingPackaged materials shall be clearly marked or labeled to indicate product, brand name, the manufacturer,and the weight of the material contained therein. Similar information shall be provided in the shipping advices accompanying theshipment of bulk materials.6. Requirements for Bases to Receiv
45、e Portland Cement-Based Plaster6.1 Metal bases and accessories used to receive plaster shall be installed in conformance with Specification C1063, except asotherwise specified. Non-metallic bases used to receive plaster shall be installed in conformance with Specification C1787.NOTE 3All metal, or P
46、VC, or CPVC plastic members should plaster bases and accessories shall be free of deleterious amounts of rust, oil, or otherforeign matter, which could cause bond failure or unsightly discoloration.6.2 Surfaces of solid bases to receive plaster, such as masonry, stone, cast-in-place or precast concr
47、ete shall be straight and truewithin 14 in. in 10 ft (2.1 mm/m) and shall be free of form oil or other elements, which would interfere with bonding. Conditionswhere the surfaces are out of tolerance shall be corrected prior to the application of the plaster. Ferrous-containing form ties orother obst
48、ructions shall be removed or receded a minimum 1/8 in. (3 mm) below the surface of the solid base and treated with acorrosion-resistant coating. Non-ferrous protuberances shall be permitted to be trimmed back even with the surface of the solidbase.6.2.1 Solid surfaces shall have the suction (ability
49、 to absorb water) or surface roughness, or both, to provide the bond requiredfor the plaster.6.2.2 Smooth or nonabsorbent solid surfaces, such as cast-in-place or precast concrete, shall be prepared to receive portlandcement plaster by one of the following methods:6.2.2.1 Sandblasting, wire brushing, acid etching, or chipping or a combination thereof,6.2.2.2 Application of a dash-bond coat applied forcefully against the surface, left untroweled, undisturbed, and moist cured forat least 24 h, or6.2.2.3 Application of
