A Comprehensive Review on the use of Reclaimed Wastewater in Cementitious Materials: Fresh, Mechanical, Microstructure, and Durability Aspects

Abstract

Concrete is the second most consumed material globally after water. In 2012, the concrete industry accounted for about 9% of global industrial water use, approximately 1.7% of total global water withdrawals. By 2050, around 75% of the water required for concrete production is expected to come from regions facing water stress. To reduce this pressure on freshwater resources, using wastewater (WW) in cementitious systems has been proposed as a sustainable alternative. However, a comprehensive understanding of how various WW types, such as domestic, industrial, and treated municipal sources affect concrete properties remain limited. This study addresses this gap through a combined bibliometric and systematic review. A five-stage methodology was adopted, beginning with formulating research objectives and data collection from the Scopus database using targeted keywords. A total of 91 relevant publications from 2000 to 2023 were analyzed using the Biblioshiny interface of the Bibliometrix R package to discover trends in research focus and geographic distribution. A subsequent systematic review examined the effects of WW on fresh, mechanical, microstructural, and durability properties of cement-based materials. Findings show a clear increase in publications over the last two decades, indicating rising interest in sustainable concrete. Approximately 45% of studies reported improvements in compressive strength with WW use, 35% found significant increases, and 20% observed no major change. These variations are largely attributed to the chemical composition of WW, including factors like total dissolved solids, suspended solids, biochemical oxygen demand, and chemical oxygen demand. An inverse relationship between workability and strength was often well-known. Higher WW replacement ratios typically led to increased porosity, chloride diffusion, and water absorption, posing durability concerns such as reinforcement corrosion. SEM images further showed reduced calcium-silicate-hydrate (C-S–H) gel development and increased cracks and voids. Despite growing interest, research gaps remain. Most studies focus on treated municipal WW, with limited attention to other sources. Durability aspects such as sulfate and acid resistance are underexplored, and the impact of WW in curing processes is rarely assessed. More in-depth studies on specific WW treatment methods and their influence on cementitious performance are needed.