Influence of water and aluminium powder content on the properties of waste-containing geopolymer foams

The production of low thermal conductivity geopolymers has attracted increasing attention over the past years due to their low cost and green processing technology. In this work, light and porous geopolymers were produced by the proper association of aluminium content and solid-to-liquid ratio. This allowed the production of very low thermal conductivity geopolymers (78.6 mW/m K) exhibiting homogeneous pore size distribution which suggests their use in thermal insulating applications. Moreover this study also reduced the existing knowledge gap concerning the fresh-state characterization of foamed geopolymer slurries. The influence of aluminium powder, curing temperature and solid-to-liquid ratio on the calorimetric response of biomass fly ash-containing geopolymer slurries was evaluated. The calorimetric response of geopolymer slurries shows that the time needed to reach the maximum temperature decreases when the aluminium powder rises, thus shortening the open time before in situ application. It was also found that the geopolymerization rate is governed by the curing temperature.