Optimizing the economic, environmental and technical performance of concrete mixes with fly ash and recycled concrete aggregates

Abstract This study answers an important question that may arise when selecting a sustainable concrete, namely “concrete mixes containing low cement and recycled aggregates are a sustainable solution?” To answer this question, this study shows how to optimize concrete mixes in terms of technical performance, and economic and environmental life cycle. Firstly, the weight to be considered for each of these dimensions of performance depends on the concrete application (e.g. residential house and high-rise building) and on the consumer’s requirements (e.g. business as usual, green, strength, service life and cost scenarios). In this study, concrete mixes containing recycled concrete aggregates (RCA) and/or fly ash (FA) are optimized to be used in sustainable residential houses. For that purpose, the CONCRE Top methodology (developed by the same authors of this study) was applied to these concrete mixes by considering a “green scenario”. The results show that, for sustainable residential houses, the concrete mixes made with high incorporation ratios of FA and RCA are considered the best option.