CHARACTERISTICS OF MORPHOLOGY OF THE INTERFACE BETWEEN CEMENT PASTE AND FLY ASH

Using SEM and EDS, the characteristics of morphology within the interfacial zone between fly ash and cement paste added with fly ash was studied. The results show that there are three states for the surface of fly ash particles in the early period of hydration: (1) enveloped with CSH mono film, (2)enveloped with CH CSH duplex film and (3) inserted in the block of portlandite. However, in the later age of hydration, the surface of fly ash particles has been reacted fully with hydration products of cement, and formed some reaction products, e. g. densed granular or ring shaped gel.