Downstream processing of End-of-Life concrete for the recovery of high-quality cementitious fractions

Abstract

The clinker in cement largely determines the environmental footprint of concrete. Therefore, concrete recycling should focus on retrieving high-quality cementitious fractions to replace clinker. This requires a shift from current traditional recycling techniques towards innovative recycling methods, enabling recovery of not only clean secondary aggregates, but also residual cementitious fines (RCF), potentially eliminating the carbon dioxide emissions associated with them. The production and upcycling of RCF offer new implementation routes that were previously deemed unfeasible. However, the properties of RCF may vary based on their origin, affecting their replacement and upcycling potential. Consequently, assessing the original concrete quality, with a focus on the binder type, before demolition is important. A handheld x-ray fluorescence technique appears promising for this purpose. To achieve effective separation of clean secondary aggregates from the original cementitious content, innovative crushing and separation techniques are needed. Additionally, electrostatic separation shows significant research potential for further optimizing RCF.