CELLULAR GRAVEL PRODUCED FROM RESIDUAL ALUMINO-SILICATE MATERIALS (FLY ASH, METAKAOLIN, SLAG, AND ALKALINE EARTH ALUMINO-SILICATE GLASS) BY NONCONVENTIONAL TECHNIQUES

Abstract

New manufacturing recipe of glass waste-based foam glass gravel for special applications in construction was designed, tested, and presented in this paper. The work originality is the use of alumino-silicate materials in the form of waste (fly ash, blast furnace slag, alkaline earth alumino-silicate glass waste) as well as in the natural state (metakaolin) widely available in nature. Especially, in this work it was chosen the use of a waste of alumino-silicate glass recovered from halogen lamps, similar by chemical composition with the other materials adopted to constitute the material mixture. Three variants using a solid (SiC) and liquid (glycerin), respectively, blowing agent were tested, the mixtures being sintered and foamed at temperatures between 850-940 ºC. The heating was made by the economic and ecological technique of microwave irradiation. All tested versions led to obtaining cellular gravel types with characteristics suitable for special applications in construction, similar to industrially made foam glass gravel. Being more suitable for load-bearing properties, the variant made with alumino-silicate glass waste and glycerin associated with sodium silicate solution was chosen as the optimal alternative.