Flexural strength of glass-ceramic for structural applications

In order to characterise the design strength of an innovative type of glass-ceramic with a view to structural applications, 4-point-bending and Ring-on-Ring biaxial bending tests have been performed. Strength is comparable with that of tempered glass but remarkably, the material breaks into large pieces like annealed glass. Interpreted through Weibull-type probability distributions, the data show much lower dispersion with respect to glass. Additional tests performed at different load rates have allowed an evaluation of the effects of static fatigue. Using a phenomenological model of equivalent-crack growth, a method is presented to calculate the decay of strength with loading time. As expected, this material is proven to be less sensitive than glass to this type of degradation.