Visco-elastic behavior of blended cement pastes at early ages

This study aims at elucidating the visco-elastic behavior of hardening blended cement pastes, focusing on uni-axial basic compressive creep tests at early loading ages. Cement pastes with Portland cement only or blended with quartz or fly ash (both at a substitution level of 49% by volume of the total solids) were subjected to different loading scenarios. The results show that both blended systems had higher creep than pure cement paste at early ages and that the creep compliance of the blended system with fly ash was higher than with quartz. While this difference is in part due to the restraining effect of the elastic phases, the amount of C-S-H and the porosity, dissolution creep may also play a role. A numerical algorithm with generalized Kelvin-Voigt chain model was developed and it was capable of predicting with good accuracy the strain evolution of the blended cementitious materials at early ages.