1、Designation: C198 09Standard Test Method forCold Bonding Strength of Refractory Mortar1This standard is issued under the fixed designation C198; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in
2、 parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the bond-ing strength of air-setting refractory mortar by determining theflexural strength (modulus
3、 of rupture) at room temperature ofoven-dried brick-mortar joints.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard d
4、oes not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility 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 St
5、andards:2C78 Test Method for Flexural Strength of Concrete (UsingSimple Beam with Third-Point Loading)C133 Test Methods for Cold Crushing Strength and Modu-lus of Rupture of RefractoriesC651 Test Method for Flexural Strength of ManufacturedCarbon and Graphite Articles Using Four-Point Loading atRoom
6、 TemperatureE4 Practices for Force Verification of Testing MachinesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Significance and Use3.1 The data developed by this test metho
7、d show thebonding strength and intrinsic strength of different qualities ofair-setting mortar. The procedures described in this test methodmeasure the bonding strength and intrinsic strength of air-setting mortars when used with specific brands or lots ofrefractory brick.3.2 Note that it is possible
8、 to obtain results with thesemethods for brick and mortar combinations which are incom-patible for use at high operating temperatures. The user mustdetermine this compatibility. Only brick and mortar combina-tions known or intended to be compatible for a particular useshould be tested.3.3 Properties
9、 of the brick, including its strength, apparentporosity, and pore size distribution, can affect the measurementof both the bonding strength of the brick-mortar composite andthe intrinsic strength of the mortar. The average modulus ofrupture of the test brick, as determined by Test Method C133,should
10、 exceed that expected for the mortar being tested. Thetesting of specific brands or lots of brick and mortar ispreferred.3.4 Three modes of failure are available: the break mayoccur within the brick itself, at the brick-mortar interface, orwithin the mortar itself. The latter provides a practical me
11、a-surement of the strength of the mortar itself and is thepredominant mode of failure with the four-point flexure testdescribed. The three-point flexure test measures the failurestrength of the brick-mortar composite. Failure within the brickitself suggests that either the particular brick contained
12、 aserious flaw, or that the mortar joint strength is of the samemagnitude or greater than that of the refractory brick. Themode of failure should always be reported in the final report.3.5 A ruggedness test for this test method3performed in1985 found the following variables to be rugged: specimen si
13、ze(2.5 to 3.0 in.), mortared surface (cut versus uncut), jointthickness (116 to18 in.), pulling of rods (fast versus slow), theloading rate (500 to 1000 lbf/min), the method of loadapplication (3- versus 4-point), and the operator.1This test method is under the jurisdiction of ASTM Committee C08 onR
14、efractories and is the direct responsibility of Subcommittee C08.01 on Strength.Current edition approved Dec. 1, 2009. Published January 2010. Originallyapproved in 1945. Last previous edition approved in 2008 as C198 02 (2008).DOI: 10.1520/C0198-09.2For referenced ASTM standards, visit the ASTM web
15、site, 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.3Supporting data on ruggedness testing is available from ASTM International.Request RR:C08-1008.1Copyright ASTM
16、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.6 The cold bonding strengths of refractory mortars ob-tained by this test method are suitable for use in research anddevelopment, quality control, and for establishing and evalu-ating compliance wit
17、h specifications between producers andconsumers.4. Apparatus4.1 BrickAt least five 9 by 414 by 212-in. (230 by 114 by65-mm) straight brick having plane surfaces and true rectan-gular shape and an average modulus of rupture higher than thatexpected from the mortar under test, when determined inaccord
18、ance with Test Methods C133, compose a sample.4.2 Spacing RodsTwo joint-thickness spacing rods madeof116-in. (2-mm) diameter drill rod cut into 4-in. (102-mm)lengths.4.3 OvenAdrying oven to accommodate at least five 9-in.(230-mm) straight brick standing on end, and for use at 220 to230F (105 to 110C
19、).4.4 Testing MachineA standard mechanical or hydrauliccompression testing machine conforming to the requirementsof Practices E4 and having a sensitivity of 20 lbf or less in therange from 0 to 4000 lbf (17.8 kN) may be used.4.5 Loading FixtureThe fixtures shall provide load bear-ing blocks which en
20、sure that the forces are applied normal tothe beam without eccentricity. The directions of loads andreactions may be maintained parallel by judicious use oflinkages, roller bearings, and flexure plates. Eccentricity ofloading can be avoided by the use of spherical bearings.4.5.1 Test Methods C133 pr
21、ovide illustrations of three-pointloading fixtures which meet the above requirements. Oneacceptable four-point loading fixture is illustrated in TestMethod C78. Another is illustrated in Test Method C651. Thespan length, L, of the support blocks shall be 7.00 6 0.05 in.(178 6 1 mm). The span length,
22、 l, of the load-applying blocksfor four-point loading shall be 2.33 6 0.05 in. (59 6 1 mm)(see Figs. 1 and 2).5. Sampling5.1 Wet MortarsThe sample of mortar shall be a preparedtest sample of about 10 lb (4.5 kg) (approximately12 gal (1.89L). If the weight of the commercial container is appreciablymo
23、re than 10 lb, the contents of the container shall bethoroughly mixed in the container, or transferred without lossto a clean impervious receptacle of larger size and mixedthoroughly to a uniform consistency. A10 lb test sample shallthen be taken and placed in a suitable covered containerresistant t
24、o the possible corrosive action of the mortar.5.2 Dry MortarsThe sample of mortar submitted shall bea prepared test sample of 10 lb (4.5 kg) or a larger quantity,such as a 50 or 100-lb (23 or 45-kg) bag from which a 10-lb(4.5 kg) sample may be obtained using acceptable samplingprocedures. The 10-lb
25、(4.5 kg) sample should be thoroughlymixed with water to a uniform, troweling consistency andstored in a covered container (resistant to possible corrosiveaction by the mortar) for at least 16 h prior to the test.NOTE 1Reaction of phosphoric acid or aluminum phosphate withmetallics may cause the deve
26、lopment of hydrogen gas in some mortars.Therefore, the container should be covered only to minimize moistureloss, not tightly sealed.6. Procedure6.1 Cut each of the bricks of the sample (see Note 2) intotwo equal parts on a plane parallel to the 212 by 414-in. (65 by114-mm) face. Use the uncut 212 b
27、y-414 in. face of each dryhalf-brick to form the mortar joint. The test mortar shall be oftroweling consistency; this may require the addition of smallamounts of water, followed by thorough mixing. Place ap-proximately double the quantity of mortar required to form ajoint116 in. (2 mm) in thickness
28、on the uncut and horizontallyplaced face of one half-brick. Place two spacing rods in themortar parallel to the 212 in. (65 mm) edges of the brick and34in. (19 mm) from each edge. Then place the uncut face of theother half-brick on the mortar. Force out the excess mortar inNOTE 1This apparatus may b
29、e used inverted. If the testing machine applies a force through a spherically sealed head, the center pivot may be omitted,provided one load-applying block pivots on a rod and the other on a ball.NOTE 2 1 in. = 25.4 mm.FIG. 1 Diagrammatic View of a Suitable Apparatus for Flexure Test of Refractory M
30、ortar Joints, Four-Point Loading MethodC198 092the joint by pressing on the top half-brick and at the same timemoving it with a to-and-fro motion in the direction of the 412in. (114 mm) dimension of the brick, using the spacing rods asrollers.6.1.1 A total of five movements in each direction shall b
31、egiven, and the distance of travel for the top half-brick should be14 in. (6 mm) from center in each direction. Withdraw the rodsand clean the excess mortar from the surface of the joint.Allowthe joints, prepared in this manner, to air-dry undisturbed atroom temperature for 24 h, and then oven-dry a
32、t 220 to 230F(105 to 110C) for 18 h (overnight). Upon removal from theoven, allow them to cool by radiation until cool to the touch (6h maximum).NOTE 2A thin abrasive cut-off wheel is useful for “sawing” the 9 in.(230 mm) brick in half.6.2 Place and center the 9 by 414 in. (230 by 114 mm) faceof the
33、 test specimen on the support blocks. Place and center theload-applying block(s) on the opposite face of the specimenensuring that the applied loads and reactions will remainparallel during testing.6.3 The load shall be applied in accordance with TestMethod C133, except that, when using a hydraulic
34、testingmachine, the load shall be applied at the rate of 1000 lbf (4.45kN)/min.7. Report7.1 For three-point loading, calculate the modulus of rup-ture using Eq 1:MOR 5 3PL/2bd2(1)where;MOR = modulus of rupture, lbf/in2(MPa),P = maximum applied load at rupture, lbf (N),L = span between supports, in.
35、(mm),b = breadth or width of specimen, in. (mm), andd = depth of specimen, in. (mm).7.2 For four-point loading, calculate the modulus of ruptureusing Eq 2 or Eq 3:7.2.1 If the fracture initiated in the tension surface withinthe middle third of the span length:MOR 5 PL/bd2(2)7.2.2 If the fracture ini
36、tiated in the tension surface outside ofthe middle third of the span length by not more than 5 % of thespan:MOR 5 3Pa/bd2(3)where:a = average distance between the line of fracture and thenearest support on the tension surface of the beam, in.(mm).7.2.3 If fracture occurs in the tension surface outsi
37、de of themiddle third of the span length by more than 5 % of the spanlength, discard the results of the test.7.3 The report shall include:7.3.1 The identity (brand, description, lot number, etc.) ofthe mortar and brick tested;7.3.2 The type of testing performed, three- or four-pointloading;7.3.3 The
38、 number of specimens composing a sample;7.3.4 Individual dimensions, maximum applied load, calcu-lated modulus of rupture, and the mode of fracture (that is, inbrick, at brick-mortar interface or within mortar) observed foreach specimen;7.3.5 The mean modulus of rupture and its standard devia-tion f
39、or the sample.8. Precision and Bias8.1 PrecisionThe precision of this test method is based onan interlaboratory study of C198, Standard Test Method forCold Bonding Strength of Refractory Mortar, conducted in1989. A total of three laboratories participated in this study, butonly two reported 4-point
40、results. Each lab determined fivereplicate test results for two materials (dry and wet mortar).Every “test result” reported represents an individual determi-nation. Except for the use of only three laboratories, PracticeE691was followed for the design and analysis of the data; thedetails are given i
41、n ASTM Research Report No. C08-1008.8.1.1 Repeatability limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theyFIG. 2 Beam with Four-Point LoadingC198 093differ by more than the “r” value for that material; “r”istheinterval representing the critical difference
42、between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.8.1.1.1 Repeatability limits are listed in Tables 1 and 2.8.1.2 Reproducibility limit (R)Two test results shall bejudged not equivalent if they differ by more th
43、an the “R” valuefor 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.8.1.2.1 Reproducibility limits are listed in Tables 1 and 2.8.1.3 The above ter
44、ms (repeatability limit and reproducibil-ity limit) are used as specified in Practice E177.8.1.4 Any judgment in accordance with 8.1.1 and 8.1.2would normally have an approximate 95 % probability ofbeing correct; however, the precision statistics obtained in thisILS must not be treated as exact math
45、ematical quantities thatare applicable to all circumstances and uses. The limitednumber of materials tested and laboratories reporting resultsguarantees that there will be times when differences greaterthan predicted by the ILS results will arise, sometimes withconsiderably greater or smaller freque
46、ncy than the 95 %probability limit would imply. Consider the repeatability limitand the reproducibility limit as general guides, and the asso-ciated probability of 95 % as only a rough indicator of whatcan be expected.8.2 BiasAt the time of the study, there was no acceptedreference material suitable
47、 for determining the bias for this testmethod, therefore no statement on bias is being made.8.3 The precision statement was determined through statis-tical examination of 50 results, from three laboratories, per-forming two analyses on two materials.8.3.1 To judge the equivalency of two test results
48、, it isrecommended to choose the material closest in characteristicsto the test material.9. Keywords9.1 cold bonding strength; flexural strength; high tempera-ture; modulus of rupture; refractory mortarASTM International takes no position respecting the validity of any patent rights asserted in conn
49、ection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International H
