The present work deals with a phase composition study of the products of the pozzolanic reaction of enriched kaolin from "Senovo" deposit (Bulgaria) with saturated solutions of Ca(OH) 2. Experimental runs are carried out at two temperatures – 23 and 100 o C. The results obtained show that at a temperature of 100 o C two well distinguished crystalline hydrate phases are formed: gehlenite hydrate and hydrogarnet. Both hydrates are located in the surface layer of the silica gel, which forms a

more »

... e-fiber-like shape structure. After termination of the reaction and curing the samples in the course of 3 months at a temperature of 20 o C in saturated water vapour medium, the gehlenite hydrate is converted into hydrogarnet, which is the stable phase under these conditions. The formation of the needle-fiber-like shape structure is characteristic of the reaction product, obtained at a temperature of 23 o C, however, no formation of crystalline hydrate phases is observed. This is probably due to a decrease of the rate of the pozzolanic reaction or to a lower rate of crystallization of the secondary products formed.