Early activation and properties of slag cement

Early age activation of granulated blast-furnace slag (BFS) and blends of slag and portland cement (OPC) has been studied. Activators include sodium-hydroxide, sodium sulfate, alum (potassium aluminum sulfate), superplasticizer, and calcium aluminate cement. Heat of hydration, x-ray phase characterization, compressive strength, viscometry, pore size distribution and related characterization studies have been made. Activated BFS-cement mortars having equivalent strengths at 1 day to OPC have been prepared, which also have 28- and 90-day strengths exceeding those of the OPC. Mechanisms of activation are discussed.