Preparation and properties of fly ash-based geopolymer concrete with alkaline waste water obtained from foundry sand regeneration process

Abstract

The aim of the research was to investigate the influences of high alkaline content foundry sand regeneration wastes incorporated with fly ash in the production of geopolymer concrete. The fly ash-based geopolymer concrete was activated using alkaline solutions of sodium silicate and sodium hydroxide. The geopolymeric products were characterized using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy and simultaneous thermal analysis. A higher compressive strength was observed in mechanical strengths test in the geopolymer and its respective foam concrete made of waste water in comparing to reference water (tap water). Furthermore, a packed arrangement and lower pore size distribution for both geopolymer and foam concrete were observed using nitrogen gas adsorption and mercury intrusion porosimetry, in contrast, to waste water and reference water.