Pore structure of blended cement paste by means of pressurization¿depressurization cycling mercury intrusion porosimetry

Concrete containing supplementary cementitious materials (SCMs) has different durability properties from that containing pure Portland cement. The durability of concrete is always associated with the properties of microstructure, especially pore structure. Pressurization–Depressurization Cycling Mercury Intrusion Porosimetry (PDC-MIP) was recently developed which can overcome the “ink bottle” effect and provide a more accurate estimation of the pore size distribution in cement-based materials. In this study, the PDC-MIP was applied to characterize the evolution of pore structure of cement pastes blended with fly ash and/or limestone powder. The results revealed that as hydration proceeds the volume of gel pores ( 0.05 um) decreased. The addition of fly ash increases the volume of gel pores (<0.01 um).