ASTM C133-24

SIGNIFICANCE AND USE 3.1 The cold strength of a refractory material is an indication of its suitability for use in refractory construction. (It is not a measure of performance at elevated temperatures.) 3.2 These test methods are for determining the room temperature flexural strength in three-point bending (cold modulus of rupture) or compressive strength (cold crushing strength), or both, for all refractory products. 3.3 Considerable care must be used to compare the results of different determinations of the cold crushing strength or modulus of rupture. The specimen size and shape, the nature of the specimen faces (that is, as-formed, sawed, or ground), the orientation of those faces during testing, the loading geometry, and the rate of load application may all significantly affect the numerical results obtained. Comparisons of the results between different determinations should not be made if one or more of these parameters differ between the two determinations. 3.4 The relative ratio of the largest grain size to the smallest specimen dimension may significantly affect the numerical results. For example, smaller cut specimens containing large grains may present different results than the bricks from which they were cut. Under no circumstances should 6 in. by 1 in. by 1 in. (152 mm by 25 mm by 25 mm) specimens be prepared and tested for materials containing grains with a maximum grain dimension exceeding 0.25 in. (6.4 mm). 3.5 This test method is useful for research and development, engineering application and design, manufacturing process control, and for developing purchasing specifications. SCOPE 1.1 These test methods cover the determination of the cold crushing strength and the modulus of rupture (MOR) of dried or fired refractory shapes of all types. 1.2 The test methods appear in the following sections: Test Method Sections Cold Crushing Strength 4 to 8 Modulus of Rupture 9 to 13 1.3 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. 1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.