Durability of air-cooled slag cement pastes in seawater

Abstract EN

In the operation of a blast furnace the iron oxide ore is reduced by means of cock to metallic iron, while the silica and alumina constituents combine with the lime and magnesia to form a molten slag which collects on the top of the molten iron.

When the slag is allowed to cool slowly, it solidifies into a crystalline material known as “ air-cooled slag”.

This slag has no or very little, cementing properties.

On the other side, when the blast–furnace slag is cooled of amorphous glassy material and can be used in blended cement.

The aim of the present work is to study the hydration characteristics of air-cooled slag as pozzolana in blended cement and the durability of cement pastes in seawater.

The result revealed that the air cooled slag showed a hydraulic activity as seen from the results of the combined water, free lime contents and compressive strength of hardened cement pastes.

Also, the air-cooled blended cement pastes have a good resistance in seawater with comparison of sulphate resistant cement pastes up to one year.