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Carbonated cement pastes (CCP) can be used as stable carbon storage. In this work, CCP were systematically investigated as supplementary cementitious materials (SCMs)-like components used in ordinary Portland cement (OPC) paste. The fully hydrated cement pastes were pulverized into powders and then exposed to different CO 2 pressure conditions (i.e., 1.0, 2.0 and 2.5 MPa) for 24 h. These CCP powders were then mixed with OPC to form a new binder. Various fresh, hardened and microstructural properties of CCP powders and the mixtures were investigated. Initial results show that the CO 2 sequestration level of CCP increased with the growth of CO 2 pressure, and albeit a pozzolanic reaction occurred inside the mixture, the relatively higher water demand due to the use of 30% replacement of CCP led to the inferior workability and compressive strength than the control group. Finally, a conceptual model relating to the CCP-OPC paste was proposed, facilitating the comprehension of the hydration behaviours of CCP-OPC paste.