In 2018, following an international trend, a Brasilian technical standard increased the maximum content of carbonate material from 10% to 25% for Portland cement with calcium carbonate addition. This project aims to understand phase evolution during the hydration of two commercial Portland cements containing carbonate material using X-ray diffraction (XRD), focusing on the in-situ technique, which had the results compared with the conventional ex-situ method. To understand phase development during hydration, the following methodology was adopted: powdered characterization (anhydrous), cementitious pastes characterization with different hydration ages (from 15 min to 28 days), and phases assemblage progress within hydration. Complementary standardized thermogravimetry analyses were performed, and the results related to the evolution of phases. The ex-situ method was suitable to quantify the contents of constituents over time, including amorphous content, and was effective in identifying aluminate hydrates that can affect the performance of cements containing a higher quantity of calcite. The in-situ approach offers time savings, but the drawback was the phase quantification accuracy. The joint use of in-situ and ex-situ techniques can be favorable in an industrial environment, both for cement producers and for companies using it as raw material, especially in the context of new standards.