Standard Test Method for Modulus of Rupture of Refractory Materials at Elevated Temperatures

Flexural strength is determined for 1" x 1" x 6" bars at temperature in three-point bending. Price includes a 12 hour hold at the test temperature. Testing of five specimens per type/brand is recommended by ASTM.

2000°F or Less $560 $40 each
2000°F to 2300°F $615 $40 each
2300°F to 2500°F $615 $40 each
2500°F to 2750°F $795 $40 each
2750°F to 2912°F $975

$40 each

additional Hold Time at Temperature Quote Quote



Measuring the modulus of rupture of refractories at elevated temperatures has become a widely accepted means to evaluate materials at service temperatures. Many consumer companies have specifications based on this type of test.

This test method is limited to furnaces operating under oxidizing conditions. However, with modifications for atmosphere control in other test furnaces, the major criteria of this test procedure may be employed without change.

This test method is designed for progressive application of a force or stress on a specimen supported as a simple beam with center-point loading. Test apparatus designed for the progressive application of a strain may yield different results, especially since refractory materials will reach a semiplastic state at elevated temperatures where Hooke's law does not apply, that is, stress is then not proportional to strain.

This test method applies to fired dense refractory brick and shapes, chemically bonded brick and shapes, shapes formed from castables, plastics, or ramming materials, and any other refractory that can be formed to the required specimen dimension.


1.1 This test method covers determination of the high-temperature modulus of rupture of refractory brick or monolithic refractories in an oxidizing atmosphere and under action of a force or stress that is increased at a constant rate.

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.


Extracted, with permission, from ASTM C583 Standard Test Method for Modulus of Rupture of Refractory Materials at Elevated Temperatures, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the standard may be purchased from ASTM International, phone 610-832-9555, e-mail:, website:


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