Thermal and microbiological performance of metakaolin-based geopolymers cement with waste glass

In this paper, we investigated the behavior of the metakaolin-based geopolymeric matrix incorporated with waste glass. Pure metakaolin and mixtures obtained by adding different percentages (30, 40, and 50 wt%) of waste glass were consolidated via alkali activation at 50 °C. Infrared spectroscopy was able to reveal the formation of bonds in the mixtures between the clay and the glass in the geopolymeric matrix. Leaching tests were carried out to evaluate the eventual release of toxic metals, while cytotoxicity and antibacterial tests completed the environmental evaluation of the final consolidated products that showed how the mechanical performance were improved by adding different amount of waste glass under compression in the range of 18–39 MPa. Simultaneous thermogravimetry/differential thermal analysis (TG/DTA) experiments showed that about 20 wt% of water was retained in all the samples and released up to 500 K, while lower amount of water was removed by dehydroxylation in the two glass-rich mixtures because of the lower degree of reticulation i.e. lower number of hydroxyl groups underwent to condensation.