Standard Test Methods for Cold Crushing Strength and Modulus of Rupture of Refractories

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 3-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- by 1- by 1-in. (152- by 25- 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.