Development of ambient cured geopolymer binders based on brick waste and processed glass waste

The current study focuses on the development of high sustainability geopolymer binders prepared from brick waste (BW), devitrified glass waste (DGW), and metakaolin (MK) as precursors, as well as sodium glass liquid (SGL) derived from DGW as alkali hardener. An algorithmic mixture design was used to target the chemical molar ratios of SiO₂/Al₂O₃ and Na₂O/SiO₂, and the physical ratio of liquid/solid (L/S), involving curing under ambient temperature. Rheological characteristics, mechanical strengths, and microstructural properties of optimized geopolymers were investigated using rotational viscometry, compressive strength measurements, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR). The results indicated that a greater content of DGW compared to BW caused lower yield stress and plastic viscosity. Moreover, geopolymer binders made with SGL and reduced amount of commercial sodium silicate (SS) showed a stable polymer network with compact microstructure, achieving results comparable to the control mixture with NaOH solution. Also, it was possible to improve the strengths of BW binders by including a combined 50% DGW + 50% MK precursor with different contents. FTIR analyses identified the formation of a corrosive component in the form of dehydrated Si-O(Na) when SGL replaced NaOH with a similar SS amount and chemical factors, whereas more Q¹ and Q⁰ silica species was formed in hardener containing SGL with reduced commercial SS, confirming the sustainable nature of the new BW + DGW + MK binders with SGL.