Recycling of fines from waste concrete: development of lightweight masonry blocks and assessment of their environmental benefits

A significant body of research has been carried out to find suitable waste materials or industrial by-products that could replace portland cement and reduce the environmental footprint of the concrete industry. Many studies focus on technical aspects, lacking an assessment of environmental impacts associated with using these alternative materials, and the contribution to the sustainability of the sector remains unclear. In this paper, we present the development of lightweight blocks containing the finest fractions of waste concrete along with a holistic study of the developed product’s structural and environmental performance. The results demonstrate the feasibility of such a recycling strategy and its environmental benefits. However, despite replacing 60 wt.% of portland cement in the developed lightweight blocks, their carbon footprint is not negligible, and to reduce CO2 emissions in the construction sector significantly will require holistic measures that promote the reuse of whole building elements instead of their disintegration and subsequent recycling