1、Designation: C474 15Standard Test Methods forJoint Treatment Materials for Gypsum Board Construction1This standard is issued under the fixed designation C474; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. 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 These test methods cover the physical testing of jointcompound, paper joint tape, glass-mesh joint tape, and anassembly of joint
3、compound and paper joint tape.1.1.1 Joint treatment materials are specified in SpecificationC475/C475M.1.1.2 The joint treatment material described in this standardare for use with gypsum board installed in accordance withSpecification C840.1.2 The test methods appear in the following order:SectionJ
4、oint Compound Tests:Viscosity 5Shrinkage 6Check Cracking 7Putrefaction 8Joint Tape Tests:Tensile Strength 9Width 10Thickness 11Paper Joint Tape TestsDimensional Stability 12Assemblages of Paper Joint Tape and Joint Compound:Bond of Paper Joint Tape to Joint Compound 15Cracking of Joint Compound at T
5、ape Edges 14Glass-Mesh Joint Tape TestSkewness 131.3 The values stated in inch-pound units are to be regardedas standard. The values given in brackets are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 The text of this standard reference
6、s notes and footnotesthat provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsib
7、ility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C11 Terminology Relating to Gypsum and Related BuildingMaterials and SystemsC472 Test Methods fo
8、r Physical Testing of Gypsum, Gyp-sum Plasters and Gypsum ConcreteC475/C475M Specification for Joint Compound and JointTape for Finishing Gypsum BoardC840 Specification forApplication and Finishing of GypsumBoardC1396/C1396M Specification for Gypsum BoardD685 Practice for Conditioning Paper and Pape
9、r Productsfor TestingD828 Test Method for Tensile Properties of Paper andPaperboard Using Constant-Rate-of-ElongationApparatus(Withdrawn 2009)3D1000 Test Methods for Pressure-Sensitive Adhesive-Coated Tapes Used for Electrical and Electronic Applica-tionsD3699 Specification for KerosineD3882 Test Me
10、thod for Bow and Skew in Woven andKnitted FabricsE100 Specification for ASTM HydrometersE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 TAPPI Standard:T411 Thickness (Caliper)
11、 of Paper, Paperboard, and Com-bined Board43. Terminology3.1 DefinitionsFor definitions of terms relating togypsum, see Terminology C11.3.2 Definitions of Terms Specific to This Standard:1These test methods are under the jurisdiction of ASTM Committee C11 onGypsum and Related Building Materials and
12、Systems and are the direct responsi-bility of Subcommittee C11.02 on Specifications and Test Methods for Accessoriesand Related Products.Current edition approved June 1, 2015. Published July 2015. Originally approvedin 1961. Last previous edition approved in 2013 as C474 13. DOI: 10.1520/C0474-15.2F
13、or 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.3The last approved version of this historical standard is refer
14、enced onwww.astm.org.4Available from Technical Association of the Pulp and Paper Industry, Technol-ogy Park, P.O. Box 105113, Atlanta, GA 30348.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 194
15、28-2959. United States13.2.1 bond, nin joint systems, the quality of adhesionbetween the paper joint tape and joint compound.3.2.1.1 DiscussionA 0 % bond means that no paper fiberis adhering to the joint compound. 100 % bond means thatthere is cohesive failure of the paper joint tape.3.2.2 check cra
16、cking, nin joint systems, short, narrowcracks randomly oriented in the surface of the dried jointcompound.3.2.3 joint compound, powder, nA drying-type or setting-type cementitious material to be mixed with water.3.2.4 joint compound, ready-mix, nA drying-type cemen-titious material that is factory m
17、ixed in ready-to-use form.4. Specimen Preparation4.1 Joint Compound, Powder:4.1.1 Mix 300 g of joint compound, powder, with approxi-mately 150 to 160 mL of water.4.1.2 Allow the specimen to stand for 30 min (Note 1),remix and adjust the temperature to 77 6 2F 25 6 1C byplacing the container holding
18、the specimen in warm or coolwater.NOTE 1Allow setting type compounds to stand for one half of theirsetting times, as determined by Test Methods C472 but not more than30 min, prior to remixing.4.1.3 Measure the viscosity in accordance with Section 5.4.1.4 If the measured viscosity is not between 480
19、and520 Brabender units, repeat 4.1.1 4.1.3 through with anincrease or decrease in water as necessary.4.1.5 Record the volume of water used to adjust the viscos-ity to 500 6 20 Brabender units (see Note 2).NOTE 2Making note of the volumes of water, in millilitres per 100 gof material, used to adjust
20、the viscosity, will facilitate specimen prepara-tion in other tests.4.2 Joint Compound, Ready-Mix:4.2.1 Remix joint compound, ready-mix, to reincorporateany separated ingredients. Adjust the temperature to 77 6 2F25 6 1C by placing the container holding the specimen inwarm or cool water.4.2.2 Measur
21、e the viscosity in accordance with Section 5.4.2.3 If the viscosity is more than 520 Brabender units, addwater to achieve a viscosity of 500 6 20 Brabender units (seeNote 2).4.2.3.1 If the original sample viscosity is less than 480 Bra-bender units, test as received.JOINT COMPOUND5. Joint Compound V
22、iscosity5.1 Significance and Use:5.1.1 This test method provides a procedure for measuringjoint compound viscosity.5.2 Sampling:5.2.1 Sampling shall be in accordance with SpecificationC475/C475M.5.3 Specimen Preparation:5.3.1 Prepare specimens in accordance with Section 4.5.4 Apparatus:5.4.1 Viscosi
23、ty Specimen Container, metal or plastic with anopen top having an inside diameter of 212 to 3 in. 65 to75 mm and a height of 212 to 3 in. 65 to 75 mm.5.4.2 Viscometer5, adjusted to operate at 78 6 1 r/min.5.4.3 Viscometer Pin (Spindle), having dimensions as fol-lows:in. mmShaft diameter 0.187 0.015
24、4.75 0.38Pin diameter 0.094 0.015 2.39 0.38Immersion depth (from bottom of spindle) 1.625 0.015 41.3 0.38Length of pin projecting from shaft 0.750 0.015 19.1 0.38Upper pin from bottom of shaft 0.313 0.015 7.95 0.38Lower pin from bottom of shaft 0.125 0.015 3.28 0.385.5 Procedure:5.5.1 Fill the visco
25、sity container with the mixed specimenuntil level with the top of the container.5.5.1.1 Remove all air bubbles by puddling the samplecontainer with a spatula and sharply rapping the bottom of thecontainer on a hard flat surface.5.5.2 Secure the filled container in the center of the viscom-eter spind
26、le platform. Position the spindle so that the samplecomes up to the immersion mark on the pin (spindle).5.5.3 Start the viscometer and record the viscosity readingon the digital display after 30 s. If the viscometer readout goesto a strip chart recorder, read the viscosity after the pen startsto tra
27、ce a straight line (usually within 1 min); if the tracingremains inconsistent, estimate the average viscosity reading.5.6 Report:5.6.1 Report the viscosity of the joint compound specimenin Brabender units.5.7 Precision and Bias:5.7.1 The precision of this test method is based on aninterlaboratory st
28、udy conducted in 2011. Seven laboratoriesusing Brookfield equipment and eight laboratories using Bra-bender equipment tested two different materials, by alternativemethods. Every test result represents an individualdetermination, and each lab was asked to report five replicateresults for each materi
29、al / instrument combination. Except forthe limited amount of data reported for several of the material/ instrument combinations, Practice E691 was followed for thedesign and analysis of the data.5.7.1.1 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not equival
30、ent if theydiffer by more than the “r” value for that material; “r” is theinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory. Repeatability limits are listed in Table
31、s 1 and 2below.5.7.1.2 Reproducibility limit (R)Two test results shall bejudged not equivalent if they differ by more than the “R” value5The sources of supply of the apparatus known to the committee at this time arethe Brabender “Visco-Corder” Model VC-E, manufactured by C.W. BrabenderInstruments In
32、c., South Hackensack, NJ. and the Brookfield R/S-SST Rheometer,manufactured by Brookfield Engineering Laboraties Inc., Middleboro, MA. If youare aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at amee
33、ting of the responsible technical committee1, which you may attend.C474 152for that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories. Reproducibility lim
34、its are listed inTables 1 and 2 below.5.7.1.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.5.7.1.4 Any judgment in accordance with statements 9.1.1and 9.2 would have an approximate 95 % probability of beingcorrect.5.7.2 BiasAt the time of th
35、e study, there was no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on bias is being made.5.7.3 The precision statement was determined through sta-tistical examination of 296 results, by alternative methods, ontwo materials (described below)
36、.5.7.3.1 Sample A: A representative conventional weightready-mixed all-purpose joint compound prepared specificallyfor the round-robin test and distributed to all testing laborato-ries.5.7.3.2 Sample B: A representative low-viscosity wall tex-ture compound prepared specifically for the round-robin t
37、estand distributed to all testing laboratories.6. Shrinkage6.1 Significance and Use:6.1.1 This test is used to measure the amount of shrinkage injoint compound. The degree of correlation between this testand service performance has not been determined.6.2 Sampling:6.2.1 Sampling shall be in accordan
38、ce with SpecificationC475/C475M.6.3 Specimen Preparation:6.3.1 Specimen preparation shall be in accordance withSection 4.6.4 Apparatus:6.4.1 Plastic or Rubber Film, approximately 5 by 5 in. 130by 130 mm. Any thin, flexible film that peels clean from apartially dried patty may be used.66.4.2 Balance,
39、 having a sensitivity of 10 mg (Figs. 1 and 2).6.4.3 Beaker, Ring Stand, and Wire Cradle (see Fig. 1).6Rubber dental dam dusted with talc, polyethylene, or PTFE films have beenfound satisfactory for this use.TABLE 1 Brookfield R/S SST (Brabender units)Material ID AverageAxRepeatabil-ityStandardDevia
40、tionSrReproduc-ibilityStandardDeviationSRRepeatabil-ityLimitrReproduc-ibilityLimitRSample A 660.0 7.6 23.6 21.2 66.0Sample B 133.6 1.8 5.7 5.2 15.9AThe average of the laboratories calculated averages.TABLE 2 Brabender VC-E (Brabender units)Material ID AverageAxRepeatabil-ityStandardDeviationSrReprod
41、uc-ibilityStandardDeviationSRRepeatabil-ityLimitrReproduc-ibilityLimitRSample A 602.7 7.2 28.3 20.1 79.3Sample B 123.1 1.9 8.0 5.4 22.4AThe average of the laboratories calculated averages.FIG. 1 Wire Cradle in KerosineC474 1536.4.4 Forced Air Drying Oven, capable of being maintainedat 90 to 120F 32
42、to 49C.6.4.5 Spatula, having a blade approximately 4 in. by12 in.100 by 13 mm.6.4.6 Steel-Reinforced Broad Knife, a 5 to 8 in. 130 by200 mm drywall broad knife reinforced by a steel bar, 1 in.25 mm wide by18 in. 3 mm thick, by the knife width,attached to the back of the knife blade14 in. 6 mm from t
43、heedge.6.4.7 Hydrometer, having a range of 0.7 to 0.8 sp gr, inaccordance with Specification E100.6.4.8 Volumetric Container, a container which has a volumebetween 25 and 300 cm3.6.5 Reagents and Materials:6.5.1 Displacement Fluids.6.5.1.1 Mineral Spirits, odorless.6.5.1.2 Kerosine (see Specificatio
44、n D3699).6.6 Preparation of Apparatus:6.6.1 Support PlatesCover three plastic or glass plateswith plastic or rubber film.6.6.2 Obtain and record the tare weight of each assembly.6.7 Calibration:6.7.1 Volumetric ContainerDetermine the container vol-ume in cubic centimetres and its tare weight in gram
45、s.6.7.2 Mineral Spirits, KerosineUsing the hydrometer, de-termine the specific gravity and record the result as density M,g/mL.6.8 Determination of Density of Wet Compound:6.8.1 Prepare a specimen to determine the density of wetcompound by weighing the specimen in the volumetric con-tainer.6.8.1.1 A
46、djust the temperature to 70 6 2F 21 6 1C byplacing the container holding the specimen in warm or coolwater.6.8.1.2 Puddle the specimen within the container with thespatula to remove entrapped air bubbles.6.8.1.3 Finish filling the container and strike off the surfaceflush with the top using the stee
47、l-reinforced broad knife.6.8.1.4 Weigh the filled container to the nearest 0.01 g.Record the weight of the filled container.6.8.1.5 Determine the net weight of the compound in thevolumetric container by subtracting the weight obtained in6.8.1.4 from the weight obtained in 6.7.1.6.8.1.6 Divide the ne
48、t weight obtained in 6.8.1.5 by thevolume of the container obtained in 6.7.1. Record the result aswet compound density G, g/mL.G 5total weight 2 container tare weightvolume of container(1)6.9 Preparation of Specimen to Determine Wet and DryVolume:6.9.1 Place approximately 30 g of specimen onto eachp
49、repared support plate (see 6.6.1).6.9.1.1 Spread the specimen into an elongated patty316 to14 in. 5.0 to 6.5 mm thick with a spatula.6.9.1.2 Remove any specimen remaining on the spatula andadd to the patty.NOTE 3The patty may be scored across its narrowest width tofacilitate breaking the patty after it is dry.6.9.1.3 Weigh and record the total weight of each patty, film,and plate.6.9.1.4 Determine the net weight of each specimen bysubtracting the tare weight of its support plate weigh
