Investigating the use of raw perlite to produce monolithic thermal insulation material

Abstract

This study investigated the production of monolithic thermal insulation material (monoper) using coarse and fine raw perlite. In this research, coarse and fine raw perlite powder was used as a filling material, and sodium hydroxide and a foaming agent were used as chemical additives. The fillers and additives were mixed in different proportions and pressed in a 60 mm-diameter cylindrical mold, and the resulting samples were dried at 105 °C in an oven until they reached a constant dry weight. The dried samples were stored in an ash oven over different temperatures and times, and then cooled at a rate of 5 °C/min. The volumes of the samples produced were calculated, their masses were determined with precision scales, and then their apparent density was calculated. The compressive strengths of the samples were tested according to the TS EN 826 standard. Pore sizes of the monoper samples were examined by SEM microscope, and the thermal conductivity coefficients were measured by the heat flow meter method. Density changes were determined according to the sintering time and temperature of the monoper samples, and their expansion coefficients were calculated. In addition, the mathematical relationship between the apparent density and the thermal conductivity coefficient for the monoper samples was demonstrated. The apparent density, compressive strength and thermal conductivity of the optimum sample were determined to be 95 kg/m3, 270 kPa and 0.0396 W/mK, respectively.