Coal gangue (CG), a byproduct of coal washing and mining, has experienced a substantial increase in production in tandem with rising energy consumption trends. The utilization of calcined CG as an additive to cementitious materials is considered a potentially effective strategy for CG management and expanding its applicability on a large scale. This research investigates the impact of calcined CG on the characteristics of blended cements by applying isothermal calorimetry, X-ray diffraction (XRD), Mercury Intrusion Porosimetry (MIP), and mechanical assessments. This paper investigates four separate binder systems: Ordinary Portland Cement (OPC), OPC incorporating 30 % calcined CG, OPC with 15 % limestone addition, and limestone calcined clay cement (LC3). The XRD analysis of the hydrate phase assemblage indicated that the hydrates in LC3 systems exhibit a notable increase, consequently leading to a significant reduction in porosity by MIP results. Furthermore, LC3 systems show greater refinement in pore structure compared to other blended cements. These findings present novel opportunities for furthering the utilization of coal gangue and extending the applications of LC3 cement.