1、Designation: C926 16cC926 17Standard 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. These requirements do not by default define a unit of work or assign responsibility for contractualpurposes, which is the purview of a contract or contracts made between contracting entities.1.2 This specification sets forth tables for proportioning of various plaster mixes and p
4、laster 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 standard. The SI (metric) values given in parentheses areapproximate and are provided for information purposes onl
5、y.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 as requirements of the specification.1.5 Details of construction for a specific assembly to achieve the requ
6、ired fire resistance shall be obtained from reports offire-resistance tests, engineering evaluations, or listings from recognized fire testing laboratories.2. Referenced Documents2.1 ASTM Standards:2C11 Terminology Relating to Gypsum and Related Building Materials and SystemsC25 Test Methods for Che
7、mical Analysis of Limestone, Quicklime, and Hydrated LimeC35 Specification for Inorganic Aggregates for Use in Gypsum PlasterC91 Specification for Masonry CementC150 Specification for Portland CementC206 Specification for Finishing Hydrated LimeC207 Specification for Hydrated Lime for Masonry Purpos
8、esC219 Terminology Relating to Hydraulic CementC260 Specification for Air-Entraining Admixtures for ConcreteC578 Specification for Rigid, Cellular Polystyrene Thermal InsulationC595 Specification for Blended Hydraulic CementsC631 Specification for Bonding Compounds for Interior Gypsum PlasteringC897
9、 Specification for Aggregate for Job-Mixed Portland Cement-Based PlastersC932 Specification for Surface-Applied Bonding Compounds for Exterior PlasteringC1063 Specification for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based PlasterC1116 Specification for F
10、iber-Reinforced Concrete and ShotcreteC1328 Specification for Plastic (Stucco) CementC1787 Specification for Installation of Non Metallic Plaster Bases (Lath) Used with Portland Cement Based Plaster in VerticalWall ApplicationsE90 Test Method for Laboratory Measurement of Airborne Sound Transmission
11、 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 and Related Building Materials and Systems and is the direct responsibility ofSubcommittee C11.03 on Specific
12、ations for the Application of Gypsum and Other Products in Assemblies.Current edition approved Dec. 1, 2016Jan. 1, 2017. Published January 2017. Originally approved in 1981. Last previous edition approved in 2016 asC926 16b.C926 16c. DOI: 10.1520/C0926-16C.10.1520/C0926-17.2 For referencedASTM stand
13、ards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an AS
14、TM 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 recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published
15、 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 C700, West Conshohocken, PA 19428-2959. United States1E492 Test Method for Laboratory Measurement of Impact Sound Transmissi
16、on 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 in Terminologies C11 and C219, except as modified herein.3.2 Definitions of Terms Specific to This Standard:3.2.1 accelerato
17、r, 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 or duringjob mixing.3.2.3 acid etching, nthe cleansing and controlled erosion of a solid surface, using an acid wash.3.2.4
18、 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 and 1000 m in diameter) disconnected air bubbles in the plaster (seeentrapped air).3.2.5 back wrap, na means of terminating
19、 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 plastic core to provide continuityof the reinforced base coat and protection for the foam plastic core.3.2.6 backplaster, nplas
20、ter 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 to the interior.3.2.8 bond, nthe state of adhesion between plaster coats or between plaster and plaster base.3.2.9 bonding
21、 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 cementitious material, na material that, when mixed with water and with or without aggregate, provides the plasticityand the
22、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, nall plaster applied before the application of the finish coat.3.2.11.2 bedding coat, na plaster coat that receives aggrega
23、te 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 work, brown coat refersto the double-up basecoat. In either use, the brown coat is the coat directly beneath the finish coat.3
24、.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 or concrete block surfaces to improve the mechanical key forsubsequent plaster coats.3.2.11.5 double-up coat, nthe brown-c
25、oat 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 fog coat, na light coat of cement and water, with or without aggregate or color pigment, applied by machine sprayto improve
26、 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 other substrate to improve appearance.3.2.11.10 three-coat work, napplication of plaster in three successive coats with tim
27、e 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.3.2.13 curing, vthe act or processes of producing a moisture environment favorable to cement hydration, resulting in theset
28、ting 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 concealed water-resistive barrier over which drainage will occur.3.2.15 entrapped air, nunintentional air voids in the plaster g
29、enerally 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 manufacturer, requiring only the addition of and mixing with water to produce plaster.3 Available from American National Standards
30、 Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.C926 1723.2.17 fiber, natural or synthetic, nan elongated fiber or strand admixture added to plaster mix to improve cohesiveness orpumpability, or both.3.2.18 floating, vact of compacting and leveling brown-coat plaster to a reasonably
31、 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 surrounds, penetrates, or deforms to lock onto the perforations orirregularities of the plaster base or previous coat of plaster
32、.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 cementitious base coat, nAbase coat containing portland cement modified with chemical admixtures(typically polymer latexes)
33、to improve characteristics of the finished product, such as workability, plasticity, water resistance, andadhesion.3.2.23 required, adjpertaining to a mandatory obligation imposed by a force outside of this specification, such as a buildingcode, project specification, contract, or purchase order.3.2
34、.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 plaster coat to provide a key for asubsequent coat.3.2.26 set, nthe chemical and physical change in plaster as it goes from
35、 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,concrete and stone masonry, clay brick, and tile.3.2.28 stucco, nportland cement-based plaster used on exterior locations.3.2.29
36、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.3.2.31 texture, nany surface appearance as contrasted to a smooth surface.3.3 Definitions of Terms Not Specific to This Standar
37、d3.3.1 contract documents, na series of several individual items that generally include drawings and specifications. Either orboth of these documents may exist for any particular project.4. Delivery and Storage of Materials4.1 Delivery:4.1.1 Packaged materials shall be delivered in factory-sealed, u
38、nopened, and unbroken packages, containers, or bundles.4.1.2 Bulk materials shall be delivered in clean transport vessels, 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 preve
39、nt subsequent contamination and segregation.5. Materials5.1 Materials shall conform to the requirements of the referenced 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.
40、5.2.2 Air-Entraining Portland CementSpecification C150, type as specified. White where specified.5.2.3 Masonry CementSpecification 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 Blend
41、ed Hydraulic CementSpecification C595, Type IP-(A), IS(70)-(A), IL-(A), and IT (S70)-(A), asspecified.5.2.6 Plastic 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 “
42、S” Hydrated LimeA hydrated lime that contains not more than 8 % unhydrated oxides when tested in accordancewith Test Methods C25. See Specifications C206 and C207 for a complete description of a Type “S” hydrated lime.5.4 Aggregates:C926 1735.4.1 Sand for Base CoatsSpecification C897. Aggregate fail
43、ing to meet gradation limits in Specification C897 shall bepermitted to be used, provided the plaster made with this sand has an acceptable demonstrated performance record in similarconstruction and climate conditions.5.4.2 PerliteSpecification C35.5.4.3 Sand for Job-Mixed Finish CoatsSpecification
44、C897.5.5 WaterWater used in mixing, application, and finishing of plaster shall be clean, fresh, suitable for domestic 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 Fibe
45、rsSpecification C1116 on alkali-resistant fibers, glass fibers, nylon, polypropylene or carbon fibers.5.8 Product MarkingPackaged 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
46、 be provided in the shipping advices accompanying theshipment of bulk materials.6. Requirements for Bases to Receive 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-meta
47、llic bases used to receive plaster shall be installed in conformance with Specification C1787.NOTE 3All plaster bases and accessories shall be free of deleterious amounts of rust, oil, or other foreign matter, which could cause bond failure orunsightly discoloration.6.2 Surfaces of solid bases to re
48、ceive plaster, such as masonry, stone, cast-in-place or precast concrete shall be straight and truewithin 14 in. (6 mm) in 10 ft (3 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 th
49、e application of the plaster. Ferrous-containing form ties orother obstructions 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 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-
