Valorization of Glass Fiber Waste (VCAS) as a Precursor in Alkali-Activated Systems Cured at Room Temperature–Influence of SiO2/Na2O Molar Ratio

Alkali-activated materials are a promising alternative for reducing CO2 emissions and raw materials consumption due to their capacity to reuse waste materials. In this study, glass fiber-derived waste (vitreous calcium aluminosilicate, VCAS) is used as a precursor in alkali-activated systems for long curing age at room temperature. Here, the influence of SiO2/Na2O molar ratio on the mechanical, mineralogical, and microstructural properties is assessed. The XRD pattern, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) studies demonstrated the evolution of microstructure even after 28 curing days yielding a dense-compact microstructure, and according to the compressive strength results in mortars, about 100 MPa in compression was achieved after 360 curing days for 0.48 and 0.55 SiO2/Na2O molar ratio, confirming the stability of this system at room temperature.