Recycling and reuse of reactive MgO cements - A feasibility study

This study investigated the recycling potential of carbonated reactive MgO cement (RMC)-based concrete systems. Calcination conditions controlled the performance of recycled samples, which were fully decomposed at 700 °C. Recycled samples demonstrated 15-20% lower strengths than original samples, attributed to changes in MgO reactivity, aggregate properties and interaction between aggregates-cement paste. Robustness of the recycling process was demonstrated via five repetitive calcination cycles applied on a single batch. Successful separation of aggregates from the surrounding cement paste before the recycling process could resolve issues associated with performance and lower the total energy requirement by only subjecting the cement paste to calcination.