Towards a sustainable built environment: evaluating alternative water sources for concrete production

PurposeThis study explores the feasibility of substituting freshwater with alternative water sources such as potable water (PW), harvested rainwater (HRW), stormwater (SW), borewell water (BW) and seawater (Sea W) in concrete manufacturing. The aim is to evaluate the potential of these alternative sources to support sustainable development, reduce environmental impact and conserve freshwater resources in the construction industry.Design/methodology/approachThe research followed established concrete production standards and evaluated the chemical properties of various water sources. Fresh concrete characteristics, including setting time, workability and mechanical properties (compressive, split tensile and flexural strength), were tested at 7, 28 and 90 days. Durability assessments utilized the Volhard assay for chloride content, RCPT for chloride permeability and a physical sulfate attack test. Additionally, a life cycle assessment (LCA) examined the environmental impacts, while an economic analysis assessed cost implications for each water source.FindingsThe results showed only minor differences of 2%–3% in the fresh and mechanical properties of concrete using alternative water sources, with no significant changes in compressive, tensile or flexural strength compared to potable water. The Rapid Chloride Penetration Test (RCPT) and Nord Test techniques showed that all water sources, except seawater, are suitable for concrete mixing, as they enhance concrete durability due to their very low chloride ion concentrations, which minimize the risk of steel corrosion. The sulfate attack, including mass loss and expansion measurements for various water sources, indicates low susceptibility to except seawater. SEM and EDS HRW and SW also showed denser microstructures compared to Potable Water, indicating the absence of voids or cracks and the formation of ettringite needles, while seawater posed challenges due to high chloride content and corrosion risks. The LCA indicated that SW had the lowest environmental impact, while seawater posed substantial challenges. The economic analysis confirmed SW as the most cost-effective option, with all sources meeting production standards except seawater.Originality/valueThis study provides new insights into the sustainable use of non-potable water sources in concrete manufacturing. It demonstrates the viability of using HRW, SW and BW as alternative water sources to potable water, supporting sustainability goals in construction while conserving vital freshwater resources and reducing environmental impact.