Scanning electron microscopic studies on tricalcium aluminate hydrate pastes after hydration in presence of inorganic admixtures

Tricalcium aluminate is considered as one of the most important main inorganic compounds that constitute cement. it plays an important role in controlling hydraulic characteristics of cement and strength development of concrete. although its percent do not exceed (7-12%), of the total essential compounds constituting cement, but it acquired special importance through its capability of reserving cement in a form of a paste, since can be handled easily during construction when water is added to cement. it is responsible of setting time in cement mixture so can be adjusted according to different whether conditions. to adjust setting time, organic orinorganic compounds must be added to cement mix in the presence of water to accelerate or retard hydration process according to the type of added admixture. the object of this work is to study the change in morphology and microstructure of tricalcium aluminate pastes after hydration in presence of different inorganic admixtures (ca(oh)2, al(oh)3, caso4 hydrate and cacl2 ) at different periods of hydration (1 hr, 3 hr, 7 hr, 1 day, 7days, 14 days and 28 days) using scanning electron microscopy (sem) measurements