Physical and chemical effects of El Hadjar slag used as an additive in cement-based materials

ABSTRACT Granulated blast furnace slag is currently one of the most important sources of materials for the production of blended cements. Since 1999, the use of slag in France has increased by 52% while the increase in clinker production has not exceeded 13%. In times of shortage, the high demand for slag is not always easy to satisfy, and new sources of supply need to be found. The furnace slag of El Hadjar (Annaba, Algeria) comes into this category. The paper deals with the characteristics and reactivity of this slag. A comparison with European slags shows that, although it fulfills all Standards requirements, the El Hadjarslag has slow reaction kinetics. The activity, measured on the compressive strength of mortars whose binder contains 10 to 100% slag of four finenesses ranging from 2500 to 4000 cm2/g, strongly depends on the slag fineness. The activity is quantified by using an approach which separates the effect of cement dilution from the physical and chemical effects of the slag.