Assessing the frost resistance of illite-based ceramics through the resonant frequency of free vibration and internal damping

Abstract

Experimental samples with porosity ranging from 6 % to 50 % were prepared by sacrificing template method from illite-rich clay. The frost resistance was assessed by measuring the shift in resonant frequency of free flexural vibration of prismatic samples and by the change of internal damping due to freeze-thaw cycles. Resonant frequency was determined by the impulse excitation technique and internal damping of the material was evaluated from the width of resonant peak. Samples were saturated with water and subjected to freeze-thaw cycles in the temperature range from –22 to 20 °C. Resonant frequency and internal damping were measured after 50, 100, 200, and 300 freeze-thaw cycles. Resonant frequency drops with increasing number of freeze-thaw cycles, and the effect is more pronounced in the case of samples with higher porosity. Internal damping of material was not found to be a suitable quantity for assessing the frost damage.