A recently-developed technique for studying time-dependent properties of cement-based materials is presented.It is based on the replacement of a certain volume of cement/binder grains that would remain unhydrated at a specific early-age hydration stage with an equal volurre of inert rigid inclusions.The result is the creation of an "equivalent system" with microstructure mimicking the one achieved at that pre-defined early-age hydration stage by the original cementitious system ("real system").Such equivalent system is at equilibrium: it does not change over time.This approach allows studying critical, time-dependent properties such as transport properties,volume changes and creep on unchanging systems, decoupling these processes from otherwise ongoing hydration.In this study, the validity of this technique is investigated and applied to three mortar systems: an OPC system and two blended systems with slag and fly ash, respectively.Compressive strength and elastic moduli results show satisfactory equivalence between the real and equivalent systems.Further, microstructural characterization by means of mercury intrusion porosimetry (MIP) shows comparable results in terms of total porosity.