Carbon Capture and Utilization by mineralization of cement pastes derived from recycled concrete

Abstract

AbstractReduction of CO2 emissions associated with cement production is challenging in view of the increasing cement demand and the fact that major part of the emissions originates from the main raw material used - limestone - which can be only to extremely low amount substituted. A Carbon Capture and Utilization (CCU) approach based on mineralization of fines derived from concrete appears to be a viable alternative to reduce these emissions. The CO2 sequestration and the reactivity of the obtained carbonated recycled fines is experimentally demonstrated for lab as well as industrial materials for different mineralization conditions. It is shown that all CO2 originally released by limestone calcination during clinker production can be sequestered by the full carbonation of the fines within a short time. Upon full carbonation, gels with pozzolanic properties form in the fines irrespective of the conditions tested. The carbonated fines have specific CO2 savings more than 30% higher than the simple clinker replacement by limestone.