ASTM C1144-89(2004)

The splitting tensile-strength test can be used only on brittle waste materials such as ceramics, glass, concrete, or other materials that also have tensile fracture strengths that are less than one third of the compression strengths.

The test cannot be used for metal-matrix, bituminous, plastic, or coated-particle waste forms.

The strength values derived from this test cannot be applied to compressive-stress impact failure. The results apply only to tensile-stress failure. A separate compression-strength test, in which a cylindrical specimen is loaded on the flat surfaces, is required to determine compression strength along the lines of Test Methods C 39, D 2938, and C 773. Failures caused by impact must be determined in a separate test.

This test method is applicable only to brittle solids because these are the only materials that fail under a definable stress state for the test specimen geometry and loading. For instance, extensive local shearing at or near the loading points that will also occur for plastically deformable solids, such as ductile metals or viscous polymers, will change the stress distribution sufficiently to invalidate the elastic-stress calculation used to obtain the tensile stress across the vertical fracture plane. Ductile materials will not, in many cases, fracture in the test.

The effect of specimen size on the measured strength of brittle materials is not determined by this test method. In some materials, such as concretes, heterogeneities may be so large that tests on larger specimens are more representative. Testing along the lines of Test Method C 496 may then be appropriate to measure splitting tensile strength.

This test method does not determine the effects of time and environment on strength, nor does it address failure under long-duration static loading.

This test method can be used as a quality-control check and for optimizing waste form processing.

1.1 This test method is used to measure the static splitting tensile strength of cylindrical specimens of brittle nuclear waste forms. It provides splitting tensile-strength data that can be used to compare the strength of waste forms when tests are done on one size of specimen.

1.2 The test method is applicable to glass, ceramic, and concrete waste forms that are sufficiently homogeneous (Note 1) but not to coated-particle, metal-matrix, bituminous, or plastic waste forms, or concretes with large-scale heterogeneities. Cementitious waste forms with heterogeneities >1 to 2 mm and 5 mm can be tested using this procedure provided the specimen size is increased from the reference size of 12.7 mm diameter by 6 mm length, to 51 mm diameter by 100 mm length, as recommended in Test Method C 496 and Practice C 192.

Note 1—Generally, the specimen structural or microstructural heterogeneities must be less than about one-tenth the diameter of the specimen.

1.3 This test method can be used as a quality control check on brittle waste forms and may be useful for optimizing waste form processing. Meaningful comparison of waste forms, however, requires data obtained on specimens of one size.

1.4 The values stated in SI units are to be regarded as the standard.

1.5 This standard may involve hazardous materials, operations, and equipment. 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. For specific hazard statements, see Section 7.