Influence of chlorides on magnesium sulphate attack for mortars with Portland cement and slag based binders

It can be concluded that the influence of Cl− on MgSO4 attack is temperature and binder type dependent. The presence of chlorides does not affect deterioration due to magnesium sulphate for OPC and HSR at an environmental temperature of 20 °C, however, it increases the degradation when BFS is used as partial binder and/or when temperature decreases to 5 °C. The presence of BFS decreases the formation of a protecting brucite layer and favours decomposition of calcium silicate hydrates to magnesium silicate hydrates. At 5 °C the degradation involves thaumasite formation, and is more equal for the different binders and quite severe.