Utilization of expired cement and aged roof tile powder in the production of sustainable geopolymer: Mechanical and physical properties

Abstract

This study deals with the production of geopolymer mortar in order to promote the recycling of waste materials as sustainable building materials. The use of waste materials such as expired cement and aged roof tiles powders in cementitious systems is of great importance in terms of increasing environmental sustainability and reducing industrial waste. Recycling these materials and using them as alternative binders contributes to more environmentally friendly and economical concrete and mortar production by reducing natural resource consumption. Expired cement and aged roof tile powder were used as binder materials and mortar specimens were produced by activating these materials with alkalis such as NaOH and Na₂SiO₃ at different ratios. Within the scope of the experimental studies, mechanical and physical properties such as unit weight, ultrasonic pulse velocity, compressive strength and bending strength were investigated in detail. The results showed that the expired cement specimens performed better especially in unit weight, ultrasonic pulse velocity and compressive strength tests, while the roof tile powder had superior properties in terms of bending strength. It was also found that the specimens activated with sodium hydroxide (NaOH) exhibited generally higher strength and performance than those activated with sodium silicate (Na₂SiO₃). These findings prove that waste materials such as both expired cement and roof tile powder can be valuable alternatives in the construction industry in terms of sustainability and waste management and reveal the potential of using these materials in geopolymer mortar production.