HIGH-STRENGTH POROUS AGGREGATE MADE BY MICROWAVE IRRADIATION HEATING TECHNIQUE OF CLAY AND GLASS WASTES FROM BUILDING DEMOLITION

Abstract

A high-strength porous aggregate for construction applications that require compression resistance and porosity has been experimentally made by direct microwave warming of residues from building demolition (clay brick and clear flat glass). Borax (4 wt. %) as a flux agent and silicon carbide (2 wt. %) as an expanding agent were incorporated into the starting mixture. Due to the high proportion of clay waste as an aluminum silicate material, the direct microwave warming was possible at very high warming rates (between 34-42.4 ºC/min) without affecting the structural homogeneity of the final product. The specific electricity consumption was extremely low (0.59-0.78 kWh/kg). The cellular glass features were: apparent specific gravity between 0.72-0.98 g/cm³, porosity between 50.3-65.7 %, heat conductivity in the range 0.161-0.197 W/m·K, compression resistance between 6.4-8.5 MPa, and pore size below 1.1 mm.