Dynamic and Static Tests for Mechanical Properties of Fired Plastic Refractories and Other More Resilient Materials

An apparatus for loading brick-sized specimens and a sensitive deflectometer are described. For a resilient material, the dynamic test, the static shear-free transverse test, and the static shear-corrected transverse test gave the same modulus of elasticity. The resilient materials were dense firebrick, glass, steel, and plaster. The elementary shear correction was satisfactory for the correction of the deflections of transverse test specimens having length-to-depth ratios ranging from 3.2 to 7.2. The dynamic modulus of elasticity, the static secant modulus of elasticity, and the static modulus of rupture were obtained for nine brands of heat-treated plastic refractories. The load-deflection curves obtained from static tests on these materials indicated plastic deformations ranging from nil to 19% of the truly elastic deformations calculated from the results obtained by the dynamic method of test. The differences in the extensibilities calculated from the static and dynamic methods of test were equivalent to these plastic deformations. For studies of thermal spalling, the static extensibilities were preferred because they approximated the strain at rupture.