1、Designation: C 631 95a (Reapproved 2004)Standard Specification forBonding Compounds for Interior Gypsum Plastering1This standard is issued under the fixed designation C 631; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers minimum requirements forbonding compounds for adhering interior gypsum plaster tostructu
3、rally sound surfaces.1.2 This specification also covers test methods for determin-ing performance requirements and physical properties.1.3 The values stated in inch-pound units are to be regardedas the standard. The SI equivalents of inch-pound units areapproximate.1.4 The following safety hazards c
4、aveat pertains only to thetest methods described in this specification: This standard doesnot purport to address all of the safety concerns, if any,associated with its use. It is the responsibility of the user of thisstandard to establish appropriate safety and health practicesand determine the appl
5、icability of regulatory limitations priorto use.2. Referenced Documents2.1 ASTM Standards:2C 11 Terminology Relating to Gypsum and Related Build-ing Materials and SystemsC 28 Specification for Gypsum PlastersC 472 Test Methods for Physical Testing of Gypsum, Gyp-sum Plasters, and Gypsum ConcreteC 51
6、1 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and Concretes3. Terminology3.1 DefinitionsFor definitions relating to gypsum andrelated building materials and systems, see Terminology C 11.4. Physical Properties4.1 General
7、The bonding compound shall be a film form-ing, non-oxidizing, non-toxic, non-flammable compositionsuitable for application by brush, roller, and spray. Thecompound shall be tinted to show, by visual inspection, whereit has been applied. The tinting material shall not show throughthe material being b
8、onded. The surfaces to which bondingcompounds are applied shall be relatively smooth, clean, anddry. Surface coatings shall be removed if their nature indicatesan unsatisfactory condition. Surfaces shall be prepared inaccordance with the manufacturers directions.4.2 ConsistencyThe bonding compound s
9、hall be of ahomogeneous nature with no settling of the solids. Thecompound shall be free of foreign matter, and when applied inaccordance with the manufacturers directions, shall coverevenly.4.3 Film CharacteristicsA dry film of the bonding com-pound shall be uniform and smooth and shall remain flex
10、ible.The film shall not be noticeably affected by mild acid or alkali.5. Performance Requirements5.1 Bonding CapabilityA dry film of bonding compoundshall be capable of bonding gypsum plaster immediately afterdrying and 10 days after drying when tested as specified inSection 12.5.2 DegradationBondin
11、g compound that separates shallbe able to be re-mixed to a uniform consistency when tested asspecified in Section 10.5.3 High Temperature StabilityThe bond strength shall benot less than 20 psi (138 kPa) when tested as specified inSection 9.5.4 Freeze-Thaw StabilityThe bond strength shall be notless
12、 than 20 psi (138 kPa) when tested as specified in Section11.5.5 Bond StrengthBond strength of a fresh sample or a 30day old sample shall be not less than 20 psi (138 kPa) whentested as specified in Section 12.6. Sampling6.1 Take a sample of not less than 1 kg from each shipmentor consignment for an
13、alysis and tests. Except in special cases,take the sample from not less than three separate containers,chosen at random. In addition, take samples from containersthat appear to be nonrepresentative, and test separately. Imme-diately place the samples in airtight glass containers andtransport to the
14、testing laboratory in these containers. Takeprecautions to reduce evaporation or drying to a minimum.1This specification is under the jurisdiction of ASTM Committee C11 onGypsum and Related Building Materials and Systems and is the direct responsibilityof Subcommittee C11.02 on Specifications and Te
15、st Methods for Accessories andRelated Products.Current edition approved Oct. 10, 1995. Published December 1995. Originallyapproved in 1988. Last previous edition approved in 1995 as C 631 95.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
16、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Thoroughly mix the bonding compound in the container if
17、there is a tendency for liquid phase separation.7. Apparatus7.1 Moist CabinetSpecification C 511.7.2 OvenA forced draft type oven, having a temperaturecontrolled at 140 6 5F(606 3 C) for high temperature testsand 100 6 5F(386 3 C) for drying of the briquets.7.3 FreezerA freezer having a controlled t
18、emperatureof106 2 F (-23 6 1 C).7.4 BalanceA balance capable of weighing at least 2500 gat a precision of 0.1 g.7.5 Timing DeviceA standard clock or watch with secondhand.7.6 TamperA tamper made up of a nonabsorptive, non-abrasive, non-brittle material and having a cross section of12in. by 1 in. (13
19、 by 25 mm) and approximately 5 to 6 in. (130to 150 mm) long. The tamping face shall be flat and at rightangles to the length of the tamper.7.7 Straight EdgeA steel straight edge not less than 4 in.(100 mm) long and not less than116 in. (1.6 mm) nor more than18 in. (3.2 mm) in thickness.7.8 SpatulaA
20、spatula with a metal blade 6 in. (150 mm) inlength and12 in. (13 mm) in width, with straight edges.7.9 Paint BrushA standard 1 in. (25 mm) wide brush,with natural or synthetic bristles.7.10 Testing MachineAny type that is of sufficient capac-ity and that is capable of applying the load continuously
21、andwithout shock at the rate of 0.05 in. (1.27 mm)/min, withprovision for adjustment of the rate of loading.7.11 Briquet MoldsThe molds for making test specimensshall be made of metal not attacked by the plaster mortar andshall have sufficient material in the sides to prevent spreadingduring molding
22、. Gang molds, when used, shall be of the typeshown in Fig. 1. The dimensions of the briquet molds shallconform to the following requirements: width of mold, be-tween inside faces, at waist line of the briquet, 1 in. (25.4 mm)with permissible variations of 60.01 in. (0.25 mm) for moldsin use and 60.0
23、05 in. (0.13 mm) for new molds; thickness ofmolds measured at the point of greatest thickness on either sideof the mold at the waist line, 1 in. (25.4 mm) with permissiblevariations of + 0.004 in. (0.10 mm) and 0.002 in. (0.05 mm)for new molds and 0.02 in. (0.5 mm) for molds in use. Theinside faces
24、at the waist line shall have a vertical slot 0.03 in.(0.75 mm) wide by 0.06 in. (1.5 mm) deep to accept thedivider. The briquet specimens shall conform to the dimen-sional requirements shown in Fig. 2.7.12 DividerSheet brass 0.02 in. (0.05 mm) thick, 1.1 in.(27.8 mm) wide by 1 in. (25.4 mm) high.7.1
25、3 Clips for Briquet Testing Machine The clips forholding the tension test specimen shall be in accordance withFig. 3.8. Conditioning8.1 Room Temperature and Humidity Maintain the airtemperature in the vicinity of the mixing and testing area, 70 65F(216 3 C). Maintain the relative humidity at 50 6 2%
26、.8.2 Temperature of the Mixing Water726 2F(226 1C).9. High Temperature Test9.1 Significance and UseThis test method provides pro-cedures for evaluating the bond strength of adhesives afterbeing exposed to accelerated aging at high temperature.9.2 Specimen PreparationFor each test specimen, transfert
27、he bonding compound, taken from the sample obtained, into astandard 1 pt (400 mL) glass container.FIG. 1 Briquet Gang MoldNOTE 11 in. = 25.4 mmFIG. 2 Briquet Specimen for Tensile Strength TestC 631 95a (2004)29.3 ProcedurePlace the specimen in the oven for 30 days.Remove the container, allow the com
28、pound to cool to roomtemperature, mix the compound to a uniform consistency, andtest as specified in Section 12.9.4 Test and RetestsTest six briquets and report theaverage of the test results. If the result of any one of the sixtests varied more than 15 % from the average, reject it andreport the av
29、erage of the other five tests. If the results frommore than two tests vary more than 15 % from the average,reject the series and retest.9.5 Precision and BiasThe precision and bias of the HighTemperature Test for determining bond strength after exposureto high temperature is essentially the same as
30、specified in thetest method for bond strength, 12.7.10. Degradation Test10.1 Significance and UseThis test method simulates theeffects of high temperature storage on the physical propertiesof bonding compound.10.2 Specimen PreparationFor each test, transfer thebonding compound, from the sample obtai
31、ned, into a standard1 pt (400 mL) glass container.10.3 ProcedurePlace the specimen in the oven for 15days. Remove the container from the oven and examine thecontents for settling and separation. Place the container back inthe oven for an additional 15 days. Remove the container andexamine the conten
32、ts again for settling and separation. Allowthe compound to come to room temperature, and mix to auniform consistency. Mix by hand, stirring with a wood, metal,or plastic paddle for not more than 5 min.10.4 Tests and RetestsBonding compound that fails to beremixed to a uniform consistency shall be co
33、nsidered to havefailed the test.10.5 ReportDetermine the extent of settling and separa-tion by measuring, and report as a percentage of the height ofthe specimen in the clear glass container, represented by thelocation of the liquid/solid interface.10.6 Precision and BiasNo information is presenteda
34、bout either the precision or bias of the degradation test formeasuring settling, separation, or the ability to be mixed to auniform consistency since the test result is nonquantitative.11. Freeze-Thaw Cycle Test11.1 Significance and UseThis test method provides pro-cedures for determining the bond s
35、trength of bonding com-pounds after being exposed to accelerated storage conditions ofalternate freezing and thawing.11.2 Specimen PreparationFor each test specimen, trans-fer the bonding compound, taken from the sample obtained,into a standard 1 pt (400 mL) glass container having a screw onor frict
36、ion fit cover.11.3 ProcedurePlace a covered specimen in the freezerfor 16 h. Remove the specimen and allow to thaw at roomtemperature for 8 h. Repeat this procedure for 5 cycles. Afterthe fifth cycle, allow the compound to come to room tempera-ture, and then test as specified in Section 12.11.4 Test
37、s and RetestsTest six briquets and report theaverage of the test results. If the result of any one of the sixtests varies more than 15 % from the average, reject it andreport the average of the other five tests. If the results fromNOTE 11 in. = 25.4 mmFIG. 3 Clips for Briquet Testing MachineC 631 95
38、a (2004)3more than two tests vary more than 15 % from the average,reject the series and retest.11.5 Precision and BiasThe precision and bias of thefreeze-thaw cycle test for determining bond strength afterexposure to alternate freezing and thawing are essentially thesame as specified in the test met
39、hod for bond strength, 12.7.12. Bond Strength Test12.1 Significance and UseThis test method provides amethod for determining the relative ability of bonding com-pound, after being subject to various simulated conditions ofaging and exposure to temperature extremes, to adhere cemen-titious materials
40、to a properly prepared substrate.12.2 Materials:12.2.1 Gauging PlasterSpecification C 28, at normal con-sistency (Test Methods C 472).12.2.2 RetarderSodium citrate.12.3 Preparation of Briquets:12.3.1 Prepare not less than six briquets for each series oftests.12.3.2 Partition the briquet molds by pla
41、cing the divider inthe slots formed at the waist of the mold.12.3.3 Add the plaster to the required amount of water andallow to soak for 30 s. Add approximately 0.1 g of retarder per100 g of plaster to achievea2to3hplaster set.12.3.4 Prepare the molds by coating them with a thin film ofmineral oil.
42、Support the molds on a lightly oiled glass or metalplate. Protect the divider from contamination with oil (wrap inplastic food wrap) and carefully insert into the mold slots.12.3.5 Cast the briquets immediately after completely mix-ing the mortar; half fill the molds and puddle the mortaruniformly w
43、ith the tamper, taking care not to displace thedivider. Slightly over fill the molds with additional mortar andrepeat the puddling. After the mortar has set, cut off the excessto a plane surface flush with the top of the mold, using a broadknife or similar implement.12.3.6 Immediately after molding,
44、 place the molds, on thebase plate, into the moist cabinet for not less than 16 h.12.3.7 Remove the briquets from the mold and store them atroom temperature and humidity for not less than 48 h.12.3.8 Examine the specimens, and discard any that have airholes or excessively rough surfaces.12.4 Procedu
45、re:12.4.1 Apply the bonding compound, in accordance withthe producers directions, to the flat waist surface of the briquetby means of a paint brush.12.4.2 Remove the divider from the mold. Place the halfbriquet, coated with bonding compound, into the mold. Fill theremaining space in the mold with gy
46、psum plaster, mixed andmolded as specified in 12.2.12.4.3 The time between coating the briquet with compoundand casting the plaster against it shall be immediately after thecompound has dried, or as recommended by the manufacturer,except when otherwise specified for a ten day waiting period.12.4.4 P
47、lace the filled briquet mold in the moist cabinet fornot less than 16 h. Remove the briquets from the molds as soonas they are thoroughly hardened, but retain them in the moistcabinet for not less than 16 h.12.4.5 The briquets are then dried to constant weight in aforced draft oven maintained at 100
48、 6 5F(386 3 C) and arelative humidity not more than 50 %.12.5 Test MethodTest the briquets immediately after re-moving them from the oven. Remove any loose particles orflash from the surfaces that will be in contact with the clips ofthe testing machine. Make sure the bearing surfaces of the clipsare
49、 clean and free of sand, and the roller bearings are lubricatedand maintained to ensure freedom of turning. Keep the stirrupssupporting the clips free of accumulations. Keep the pivots inproper adjustment so that the clips swing freely on the pivotswithout binding the stirrups. Carefully center the briquets inthe clips and apply the load continuously at the rate of 0.05 in.(1.27 mm)/min.12.6 Tests and RetestsTest six briquets and report theaverage of the test results. If the result of any one of the sixtests var
