Exploring the different stages of treated wastewater on various cement types

Recycled wastewater in construction presents an opportunity to ease freshwater scarcity while advancing sustainability. This study investigated the influences of cement type and treated wastewater source on setting time and mechanical properties of cement paste and mortar. Three cement types, ordinary Portland cement (CEM I), CEM III/A, and CEM IV/A-P, were encountered. Four plants treated wastewater versus potable water as control. Fifteen mixes were encountered; every 5 mixes addressed certain cement types along with specified treated water types. Two phases were designed; Phase I evaluated setting time in pastes and Phase II evaluated the flexural and compressive strengths of mortar specimens at 2 and 28 days of age. The significant impact of both variables was observed. CEM III/A displayed the fastest setting among the other mixes, while CEM I was the slowest. Wastewater accelerated setting versus distilled water. The mechanical performance also varied based on the cement–wastewater combination. CEM IV/A-P provided optimal strength enhancement up to 50% in flexural and 35% in compressive strength with wastewater compared to CEM I control. Results were attributed to cement–water interactions influencing hydration and microstructure. While CEM I achieved low mechanical strength with wastewater; CEM III/A, and CEM IV/A-P benefits, especially at early ages. Considerable variability highlights the complex interplay of factors governing performance. Coupled chemical-microstructural analysis was recommended to elucidate underlying mechanisms. Overall, tailored cement–wastewater selection shows promise for sustainable concrete, pending further optimization and durability testing. The study provides a platform for context-specific development of eco-efficient construction materials utilizing locally available resources.