Determination of apparent porosity level of refractory concrete using ultrasonic pulse velocity technique and image analysis

Abstract

Aim of this paper is to establish the correlation between sintering process, porosity and important thermo-mechanical property of refractory concrete, i.e. creep. Creep deformation was investigated according to standard laboratory procedure applied at three temperatures: 1200, 1300 and 1400 degrees C. Corundum and bauxite based refractory concretes were investigated. The concretes are varying in chemical and mineralogical composition. Both loss of strength and degradation of material occur when refractory concrete is subjected to increased temperature and compressive static load. Measuring of thermo-mechanical properties can indicate and monitor the changes within microstructure. Variation of refractory concrete microstructure, as a consequence of sintering process, during exposure to constant compressive load and constant elevated temperature during certain time-intervals was investigated using scanning electron microscope and Image Pro Plus program for image analysis. Obtained results of the investigation proved that creep can be useful method when type of refractory concrete is to be chosen for an application.