Chloride diffusion and oxygen permeability of mortars with low active blast furnace slag

Depending on its hydraulic activity, the use of Granulated Blast Furnace Slag (GBFS) in cementitious materials contributes to improve their durability performances. In this paper, a low reactive Granulated Blast Furnace Slag with is used in modifying mortar composition. Some durability properties of mixes containing 0, 30 and 50% of slag as substitution to OPC are studied. Diffusion and conduction of chlorides at long term are analyzed with different initial wet curing periods. Microstructure of mortars after 360 days of diffusion is observed by means of Mercury Intrusion Porosimetry. The oxygen permeability is analysed at 90 and 360 days of wet curing. The results indicate good performances to chloride diffusion of the mortars with GBFS, especially for a prolonged wet curing. Moreover, the GBFS are inefficient for oxygen permeability at 90 days but they however allow a decreasing over long term.