CALCIUM HYDROXIDE SATURATION FACTORS IN THE PORE SOLUTION OF HYDRATEDPORTLAND-CEMENT FLY-ASH PASTES

The portlandite saturation factors in the pore solution of hydrated po rtland cement paste and changes related to the addition of two types o f fly ash have been studied. Small additions (15 wt%) of fly ash incre ase portlandite supersaturation at early ages, whereas larger addition s reduce it, relative to the plain cement. At later ages, portlandite undersaturation is observed despite the continued presence of free por tlandite in the paste as observed by SEM.