Analysis of Three Generations of Recycled Concrete: an Approach Using LCA and Weighted Sum Model

Abstract

This extensive study conducted a thorough life cycle assessment of a closed-loop of recycling concrete by considering six vital criteria encompassing technical aspects (short and long-term compressive strength), environmental concerns (impacts on human health, ecosystem quality, climate change, and resource usage), and economic considerations (cost). To comprehensively assess these criteria, one potent multi-criteria decision-making technique, namely the weighted sum model (WSM) expertly employed. Two diverse weighting methodologies were utilized, the equal performance method, and the entropy method, to optimize for a range of construction applications, with a particular focus on sustainable residential buildings and housing. The results derived from this study showed that reusing concrete as a third generation of recycled concrete with 20% fly ash and 12% silica fume not only reduced costs by approximately 15% but also significantly mitigated the overall environmental impact, achieving a remarkable reduction of up to 38.5%, While reaching superior strength to the first and second generations at 28, 90, and 180 days of testing.