Life cycle cost analysis of sustainable reinforced concrete buildings with treated wastewater, recycled concrete aggregates, and fly ash

Abstract

The global excessive demand for concrete has resulted in a significant depletion of concrete natural resources and substantial release of carbon emissions in the environment. To tackle such challenges, treated wastewater (TWW), recycled concrete aggregates (RCA), and fly ash (FA) have recently been proposed as sustainable concrete constituents. From a management perspective, it is necessary to evaluate the cost-saving potential of incorporating TWW, RCA, and FA simultaneously in concrete applications. Accordingly, this study conducted a life cycle cost analysis over 60 years on 12 multi-story buildings with TWW, RCA, and FA. Various parameters were investigated, including the number of floors (20-70 floors), discount rate (0-10%), RCA-to-natural aggregate price ratio (50-200%), and construction-to-material price ratio (50-250%). Test results highlighted that buildings incorporating TWW, RCA, and FA showed 60.18% and 19.21% lower maintenance and life cycle costs compared to conventional buildings, respectively. Furthermore, the study showed that the highest cost savings are achieved with a discount rate of 2% or less. The achieved cost saving reveals the importance of utilizing eco-friendly alternatives to natural concrete ingredients. On the other hand, the number of floors, RCA-to-natural aggregate price ratio, and construction-to-material price ratio have negligible effects on the life cycle cost of the buildings.