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Abstract 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 were included. Fifteen mixes were encountered; every 5 mixes addressed certain cement types along with specified treated water types. Two phases were designed: Phase I for pastes toe value setting time and Phase II for the mortar to evaluate the flexural and compressive strengths of tool 90 specimens, 6 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 underperformed 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.
ElGazzar et al. (Wed,) studied this question.