Reactivity of blast-furnace slag in Portland cement blends hydrated under different conditions

Pastes of blended cements, with 30% and 50% slag and water:solids ratios (w/s) of 0.50 and 0.35, were hydrated at 10°C, 30°C and 50°C for up to 6 months. The reactivity of the slag fraction increased with the hydration temperature, w/s ratio and with a reduction of the replacement level of the slag. The more reactive of two slags used was that having the highest vitreous fraction; its highest degree of reaction observed was 50%, at 50°C, 30% slag and w/s ratio of 0.50, while the lowest degree of hydration was approximately 20% at 10°C, 50% slag and w/s ratio of 0.35.