HYDRATION AND PROPERTIES OF BLENDED CEMENT SYSTEMS INCORPORATING INDUSTRIAL WASTES

The characteristics of a ternary blended system, comprising granulated blast-furnace slag (WCS), from an iron steel company, Homra (GCB) from Misr Brick (Helwan, Egypt) and silica fume (SF) with 30 mass% pozzolanas and 70 mass% OPC were studied. The required water of standard consistency and setting times were measured and the physico-chemical and mechanical characteristics of the hardened cement pastes were investigated. Some selected cement pastes were tested using TGA, DTA and FTIR to investigate the variation in the hydration products of the blended cements. The pozzolanic activity of SF was higher than GCB and WCS, mainly due to its greater surface area than the other pozzolanic materials. However, GCB was more pozzolanic than WCS because it contained crystalline silica quartz in addition to an amorphous phase. The silica quartz acted as a nucleating agent which accelerate the rate of hydration in addition to its amorphous phase, which can react with liberated Ca(OH)2 forming additional hydration products.