1、Designation: C 198 02Standard Test Method forCold Bonding Strength of Refractory Mortar1This standard is issued under the fixed designation C 198; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、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 test method covers the determination of the bond-ing strength of air-setting refractory mortar by determining theflexural strength (modu
3、lus of rupture) at room temperature ofoven-dried brick-mortar joints.1.2 The values stated in inch-pound units are to be regardedas the standard. The values stated in SI units are for informa-tion only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with i
4、ts 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 Standards:2C78 Test Method for Flexural Strength of Concrete (UsingSimple Beam Wi
5、th Third-Point Loading)C 133 Test Methods for Cold Crushing Strength and Modu-lus of Rupture of RefractoriesC 651 Test Method for Flexural Strength of ManufacturedCarbon and Graphite Articles Using Four-Point Loading atRoom TemperatureE4 Practices for Force Verification of Testing Machines3. Signifi
6、cance and Use3.1 The data developed by this test method 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 o
7、r lots ofrefractory brick.3.2 Note that it is possible 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 compatib
8、le for a particular useshould be tested.3.3 Properties 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 th
9、e test brick, as determined by Test Method C 133,should 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, orwithi
10、n the mortar itself. The latter provides a practical mea-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 brickits
11、elf suggests that either the particular brick contained 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
12、found the following variables to be rugged: specimen size(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.3.6 The cold b
13、onding 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 with specifications between producers andconsumers.4. Apparatus4.1 BrickAt least five 9 by 414 by 212-in. (230 by 114
14、 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 inaccordance with Test Methods C 133, compose a sample.1This test method is under the jurisdiction of ASTM Committee C08 o
15、nRefractories and is the direct responsibility of Subcommittee C08.01 on Strength.Current edition approved Nov 10, 2002. Published June 2003. Originallyapproved in 1945. Last previous edition approved in 2001 as C 198 91 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, or
16、contact 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:C-8-1008.1Copyright ASTM International, 100 Ba
17、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 fo
18、r use at 220 to230F (105 to 110C).4.4 Testing MachineA standard mechanical or hydrauliccompression testing machine conforming to the requirementsof Practices E4and 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 provid
19、e load bear-ing blocks which ensure 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 bear
20、ings.4.5.1 Test Methods C 133 provide illustrations of three-point loading fixtures which meet the above requirements. Oneacceptable four-point loading fixture is illustrated in TestMethod C78. Another is illustrated in Test Method C 651. Thespan length, L, of the support blocks shall be 7.00 6 0.05
21、 in.(178 6 1 mm). The span length, 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 com
22、mercial container is appreciablymore 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. A 10 lb test sample shallthen be taken and placed in a su
23、itable covered containerresistant to 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 accept
24、able samplingprocedures. The 10-lb (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 phospha
25、te withmetallics may cause the development 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
26、by114-mm) face. Use the uncut 212 by-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
27、 ajoint116 in. (2 mm) in thickness 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
28、mortar inthe 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 begiven, and the distance of travel for
29、 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 at 220 to 230F(105 to 110C) for 18 h (o
30、vernight). Upon removal from theoven, allow them to cool by radiation until cool to the touch (6h maximum).NOTE 1This apparatus may be 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
31、 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 Mortar Joints, Four-Point Loading MethodC198022NOTE 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
32、414 in. (230 by 114 mm) faceof the 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 C 133, e
33、xcept that, when using a hydraulic 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
34、(N),L = span between supports, in. (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
35、 PL/bd2(2)7.2.2 If the fracture initiated 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
36、occurs in the tension surface outside 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, th
37、ree- or four-pointloading;7.3.3 The 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 ru
38、pture and its standard devia-tion for the sample.8. Precision and Bias8.1 PrecisionThe precision of the procedure for determin-ing the cold bonding strength of refractory mortars by boththree- and four-point flexure testing is being determined.8.2 BiasNo justifiable statement can be made on the bias
39、of the test method for the cold bonding strength of refractorymortar because the value of the bonding strength can bedefined only in terms of a test method.9. Keywords9.1 cold bonding strength; flexural strength; high tempera-ture; modulus of rupture; refractory mortarFIG. 2 Beam with Four-Point Loa
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43、STM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C198024
