Environmental and Economic Assessment of Eco-Concrete for Residential Buildings: A Case Study of Santiago de Cali (Colombia)

Abstract

Although the circular economy principles date back to the late 1960s, only with the recent stimulus from the European Commission and the Ellen McArthur Foundation has this concept gained attention worldwide. The City Hall of Santiago de Cali (Colombia) is implementing a circular economy model through a sustainable construction handbook and its certification. Among others, these stimulate the use of eco-concrete using fly ash and blast furnace slag coming from local industries (industrial symbiosis). Although concretes with these supplementary cementitious materials have been widely investigated regarding mechanical and durability properties, the economic and environmental impacts have been scarcely and independently evaluated, making the material selection a complex process. Therefore, this article presents the environmental and economic assessment of eco-concretes using fly ash and blast furnace slag for the design of a house located in Santiago de Cali (Colombia). The environmental and economic impacts are estimated by means of the environmental life cycle assessment (LCA) and life cycle costing (LCC), which are methodologies based on the ISO and ASTM standards implemented in the online software Building for Environmental and Economic Sustainability (BEES), which was selected for this case study. The results indicate that 40% fly ash concrete or 50% blast furnace slag would be recommended for reducing acidification or global warming potential, respectively. However, considering the existing public policies, the best option for the case study is 50% slag concrete. These results are of significant importance as they allow providing data-based recommendations for designers during the selection of the different eco-concretes. Additionally, these results might help establish a national roadmap to reduce carbon dioxide emissions from the construction sector, which are projected to continue increasing until 2050.