An Analysis of a Cement Hydration Process Using Glass Waste from Household Appliances as a Supplementary Material

Due to the significant increase in consumerism, the amount of household appliance waste has been growing, particularly in the form of glass. This study explores the possibility of using this glass (HAGw) as a replacement additive in cement-based products. The article examines the properties of HAGw, including its chemical composition (XRF), mineral composition (XRD), particle morphology, and size distribution. Scanning electron microscopy (SEM) analysis revealed that HAGw particles could partially crystallise, forming needle-shaped minerals. When replacing 10%, 20%, and 30% of cement with dispersive HAGw, the rate of cement hydration remains unchanged; however, the amount of heat released decreases proportionally to the amount of waste used. Thermogravimetric analysis indicated that substituting a part of the cement with HAGw reduces the amount of portlandite over longer curing periods, indicating the pozzolanic activity of the glass, while the quantity of calcium silicate hydrates (C-S-H) remains similar to the control sample. In the microstructure of the samples, numerous agglomerates of glass particles are formed, increasing the porosity of the cement matrix and reducing its strength. However, over time, the surface of the glass particles begins to dissolve, leading to the formation of new cement hydrates that gradually fill the voids. This process enhances cement density, increases the ultrasonic pulse velocity, and improves compressive strength, particularly after 90 days, compared to the properties of the samples at 7 and 28 days of curing.