1、Designation: C926 17C926 18Standard 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 pl
4、aster 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 only
5、.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 requi
6、red fire resistance shall be obtained from reports offire-resistance tests, engineering evaluations, or listings from recognized fire testing laboratories.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decis
7、ion on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C11 Terminology Relating to Gypsum and Related Building Materials and SystemsC25 T
8、est 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 CementC206 Specification for Finishing Hydrated LimeC207 Specification for Hydrated Lime
9、 for Masonry PurposesC219 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 Gy
10、psum PlasteringC897 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
11、Specification for Fiber-Reinforced Concrete and ShotcreteC1328 Specification for Plastic (Stucco) Cement1 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 Specifications f
12、or the Application of Gypsum and Other Products in Assemblies.Current edition approved Jan. 1, 2017Jan. 1, 2018. Published January 2017January 2018. Originally approved in 1981. Last previous edition approved in 20162017 asC926 16c.C926 17. DOI: 10.1520/C0926-17.10.1520/C0926-18.2 For referencedASTM
13、 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 Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of
14、 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 recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as pub
15、lished 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 States1C1787 Specification for Installation of Non Metallic Plaster Bas
16、es (Lath) Used with Portland Cement Based Plaster 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 MaterialsE492 Test Method for Laboratory Measu
17、rement 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 in Terminologies C11 and C219, except as modified herein.3.2 Definitions of Terms Specific
18、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 or duringjob mixing.3.2.3 acid etching, nthe cleansing and controlled erosion of a solid
19、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 and 1000 m in diameter) disconnected air bubbles in the plaster (seeentrapped air).3.2.5 b
20、ack 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 plastic core to provide continuityof the reinforced base coat and protection for the foam plas
21、tic 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 to the interior.3.2.8 bond, nthe state of adhesion between plaster coats or between plast
22、er 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 cementitious material, na material that, when mixed with water and with or without aggregate
23、, 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, nall plaster applied before the application of the finish coat.3.2.11.2 bedding coat, na p
24、laster 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 work, brown coat refersto the double-up basecoat. In either use, the brown coat is the coat d
25、irectly 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 or concrete block surfaces to improve the mechanical key forsubsequent plaster coats.3.2.
26、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 fog coat, na light coat of cement and water, with or without aggregate or color pigment, a
27、pplied 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 other substrate to improve appearance.3.2.11.10 three-coat work, napplication of plaster i
28、n 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.3.2.13 curing, vthe act or processes of producing a moisture environment favorable to ceme
29、nt hydration, resulting in thesetting or hardening of the plaster.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.C926 1823.2.14 drainage wall, na wall system in which the cladding provides a substantial barrier to water intrusion, and whi
30、ch alsoincorporates a concealed 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
31、 dry-blended by the manufacturer, requiring only the addition of and mixing with water to produce plaster.3.2.17 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 b
32、rown-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 surrounds, penetrates, or deforms to lock onto the perforations orirregularities of the plaster
33、 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 cementitious base coat, nAbase coat containing portland cement modified with chemical admix
34、tures(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 imposed by a force outside of this specification, such as a buildingcode, project specification
35、, 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 plaster coat to provide a key for asubsequent coat.3.2.26 set, nthe chemical and physical
36、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,concrete and stone masonry, clay brick, and tile.3.2.28 stucco, nportland cement-based plaster u
37、sed 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.3.2.31 texture, nany surface appearance as contrasted to a smooth surface.3.3 Definitions of T
38、erms Not Specific to This Standard3.3.1 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
39、be delivered in factory-sealed, unopened, 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 m
40、aterials shall be stored to prevent 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
41、specified. White where specified.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 spe
42、cified.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 CementPlastic Cement shall meet the requirements of Specification C1328, Standard Specification for Plastic(Stucco) Cement.NOTE 2Plastic cements are no
43、t available nationally.C926 1835.3 Type “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:5.4.1 Sand for Base CoatsS
44、pecification C897. Aggregate failing 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
45、-Mixed Finish CoatsSpecification 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 Admi
46、xturesSee 3.2.2 and A2.5.5.7 FibersSpecification 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 t
47、herein. Similar information shall 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, excep
48、t asotherwise specified. Non-metallic 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.
49、6.2 Surfaces of solid bases to receive 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 the 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 aco
