Rheological properties of aerated cement pastes with fly ash, metakaolin and sepiolite additions

• Siliceous fly ash, metakaolin and sepiolite were used in aerated cement pastes.
• Yield stress of fresh pastes was calculated with a slump test.
• Pore network was studied by imbibition methods and X-ray CT.
• Relation between rheological properties and pore network was studied.
• Addition used act as catalyst of aluminum corrosion and expansion.

Rheological properties on aerated cement pastes are studied in order to assess their influence in the pore network of the hardened aerated mortar. For this purpose, different cement types with metakaolin (MK) and sepiolite (SP) additions have been used. Volume and temperature increased during expansion; water retention and rheology of the fresh aerated cement pastes were studied to characterize the fresh mortar. Finally, pore network in the hardened aerated mortar was analyzed by imbibition methods and X-ray computed tomography. Conclusions drawn included that the incorporation of siliceous fly ashes (SFAs) in ordinary Portland cement together with additions of MK or/and SP provided the largest expansion speed increase and the lowest relative density of the foamed mortar.