ABSTRACT
The uniaxial strength of refractory materials differs considerably with regard to ultimate compressive strength versus ultimate tensile strength. The ultimate compressive strength of refractories is typically two to ten times greater than the ultimate tensile strength. This chapter addresses the ultimate strengths of refractories, and the interpretation of the American Society for Testing and Materials test results along with other parameters that surround the development of the ultimate strength. Comparison of the test results for the testing methods applied to concretes show the modulus of rupture test consistently predicts higher ultimate tensile strength values than that of the splitting tensile strength and direct, or uniaxial, tensile pull tests. In some cases the stress-strain data define the stress-strain relationships as being non-linear. As a result the modulus of elasticity is dependent not only on the sign of stress, but also on the magnitude of stress.
