This database is a comprehensive compilation of experimental results focusing on the hydration degrees of various slags over time in slag blended cements. It gathers a wide range of data extracted from multiple experimental studies conducted by researchers in the field, including Escalante [1], Kocaba [2], Schafer [3], and Lumley [4]. Each entry in the database details the experimental conditions, cement and slag chemical compositions, slag fineness and amorphism percentage, as well as the mixture conditions: temperature and water over binder ratio. The database presents the slag hydration degrees at different time intervals.