Assessing the Impacts of Treated Wastewater on Concrete's Mechanical Properties and Corrosion Resistance

Abstract

This study investigated the impacts of treated wastewater (TWW) on concrete mechanical and durability properties, addressing the growing freshwater demand in the concrete production industry amid water scarcity. This research filled a literature gap by employing an accelerated corrosion test using the impressed voltage technique. The investigation involved diverse experiments, including workability, setting time, mortar compressive strength, density, porosity, water absorption, pH value, ultrasonic pulse velocity, and half-cell potential tests. Results indicated negligible deviations compared to the control group. Both concrete groups, mixed with TWW (WT) and mixed and cured with TWW (WW), experienced a minor reduction of less than 10% in compressive and splitting tensile strengths compared to the control group, with slight exceptions. The 7-day compressive strength for the WT and WW groups reached 91.41% and 90.63%, respectively, meeting the ASTM C1602 benchmarks. Notably, after six months of curing, compressive and splitting tensile strengths markedly improved, nearly aligning with the control group. While TWW's characteristics met the ASTM C1602 criteria for mixing water, with a higher chloride content of 276.7 mg/l compared to the tap water, corrosion results showed higher rates (23.83% for WT and 24.67% for WW groups) compared to the control group, accompanied by an earlier crack appearance and increased rebar mass loss. The TWW utilization for concrete curing minimally affected the results compared to the WT group, suggesting its suitability for curing purposes. Overall, the TWW could be satisfactorily utilized in concrete production, although caution is advisable in aggressive environments where concrete is exposed.