Comparison of the Environmental Impacts of Reactive Magnesia and Calcined Dolomite and Their Performance under Different Curing Conditions

This study compared two binder systems composed of reactive magnesite cement (RMC) and calcined dolomite (D800), which were produced via the calcination of magnesite and dolomite at 800 degrees C, respectively. The environmental impacts of the production of both binders were supported with an investigation of their strengths and microstructural development in concrete samples subjected to different curing conditions. The lower energy and CO2 emissions associated with D800 production led to reduced damage to human health and the ecosystem in comparison with RMC production. The mechanical performance of both binder systems depended on their mix composition and curing conditions. Both benefited from the use of high humidity (90%), whereas elevated temperatures (60 degrees C) presented an advantage only in RMC samples. The combination of high humidity and temperature enabled increased MgO dissolution and enhanced hydration/carbonation in RMC samples, thereby leading to higher strengths. D800 samples revealed lower strengths due to their lower initial MgO contents and initial porosities. Results of this study indicated the importance of customized curing conditions depending on the mix design and binder component.