A carbonated binder system containing reactive MgO (r-MgO) and Portland cement (PC) has the potential to provide sufficient mechanical properties and reduce carbon the footprint. However, the understanding of the chemistry of hydration and carbonation of the r-MgO-PC system remains unclear. The purpose of this study is to characterize the Mg components that form blends of r-MgO and PC during hydration and carbonation. Paste specimens of r-MgO and PC with r-MgO replacement levels from 10% to 90% were cast, carbonated and examined. Experimental observations reveal that: (1) nesquehonite only occurs in the carbonated r-MgO-PC paste with r-MgO replacement ≥ 60%; (2) an amorphous phase of hydrated Mg carbonate was identified in the carbonated paste with 50% r-MgO replacement; and (3) hydrotalcite and magnesium silicate hydrate are major hydration products of r-MgO during the hydration of the paste containing 30% and 40% r-MgO, which are expected to be the precursors of amorphous hydrated Mg carbonate.

含有反应性MgO（r-MgO）和波特兰水泥（PC）的碳酸粘合剂系统具有提供足够的机械性能并减少碳足迹的潜力。然而，对r-MgO-PC系统水合和碳酸化化学的理解仍不清楚。这项研究的目的是表征水合和碳酸化过程中形成r-MgO和PC混合物的Mg组分。r-MgO替代水平从10％到90％的r-MgO和PC的糊状标本被浇铸，碳酸盐化和检查。实验观察表明：（1）菱镁矿仅存在于r-MgO替代率≥60％的碳化r-MgO-PC糊剂中；（2）在r-MgO替代率为50％的碳酸化糊中鉴定出水合碳酸镁的无定形相。