Active Standard ASTM C198 | Developed by Subcommittee: C08.01
Book of Standards Volume: 15.01
Historical (view previous versions of standard)
Significance and Use
3.1 The data developed by this test method show the bonding strength and intrinsic strength of different qualities of air-setting mortar. The procedures described in this test method measure the bonding strength and intrinsic strength of air-setting mortars when used with specific brands or lots of refractory brick.
3.2 Note that it is possible to obtain results with these methods for brick and mortar combinations which are incompatible for use at high operating temperatures. The user must determine this compatibility. Only brick and mortar combinations known or intended to be compatible for a particular use should be tested.
3.3 Properties of the brick, including its strength, apparent porosity, and pore size distribution, can affect the measurement of both the bonding strength of the brick-mortar composite and the intrinsic strength of the mortar. The average modulus of rupture of the test brick, as determined by Test Method C133, should exceed that expected for the mortar being tested. The testing of specific brands or lots of brick and mortar is preferred.
3.4 Three modes of failure are available: the break may occur within the brick itself, at the brick-mortar interface, or within the mortar itself. The latter provides a practical measurement of the strength of the mortar itself and is the predominant mode of failure with the four-point flexure test described. The three-point flexure test measures the failure strength of the brick-mortar composite. Failure within the brick itself suggests that either the particular brick contained a serious flaw, or that the mortar joint strength is of the same magnitude or greater than that of the refractory brick. The mode of failure should always be reported in the final report.
3.5 A ruggedness test for this test method3 performed in 1985 found the following variables to be rugged: specimen size (2.5 to 3.0 in.), mortared surface (cut versus uncut), joint thickness (1/16 to 1/8 in.), pulling of rods (fast versus slow), the loading rate (500 to 1000 lbf/min), the method of load application (3- versus 4-point), and the operator.
3.6 The cold bonding strengths of refractory mortars obtained by this test method are suitable for use in research and development, quality control, and for establishing and evaluating compliance with specifications between producers and consumers.
1.1 This test method covers the determination of the bonding strength of air-setting refractory mortar by determining the flexural strength (modulus of rupture) at room temperature of oven-dried brick-mortar joints.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
C78 Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)
C133 Test Methods for Cold Crushing Strength and Modulus of Rupture of Refractories
C651 Test Method for Flexural Strength of Manufactured Carbon and Graphite Articles Using Four-Point Loading at Room Temperature
E4 Practices for Force Verification of Testing Machines
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
ICS Number Code 11.020 (Medical sciences and health care facilities in general); 91.100.10 (Cement. Gypsum. Lime. Mortar)