Transformation of Waste Glasses in Hydroxide Solution

Unused glass waste represents a potentially valuable secondary raw material for the production of construction materials. This study aimed to investigate the chemical and structural transformations occurring in soda-lime container glasses of different chemical compositions when exposed to alkaline environments. Such alkaline conditions are characteristic of processes involved in the production of lime-sand materials or Portland cement-based composites, where they are essential for the occurrence of pozzolanic reactions. The investigation was conducted on powders derived from three types of container glass differing in color, which were stored in Ca(OH)₂ and NaOH solutions. The samples were analysed using X-ray diffraction (XRD), differential thermal and thermogravimetric analysis (DTA-TG), and scanning electron microscopy (SEM). The results confirmed that all tested glasses exhibited pozzolanic reactivity, although differences were observed in the composition of the reaction products and the kinetics of the transformation processes. A deeper understanding of these differences may contribute to more effective utilization of waste glass as a raw material in the manufacturing of construction materials.