Effect of magnesium sulfate on the durability of limestone mortars based on quaternary blended cements

• Evaluation of the resistance to magnesium sulfate solution of mortars containing limestone, slag and pozzolan are reported.
• The durability of mortars is taken into consideration with weight and length changes and variation of compressive strength.
• pH monitoring of the cure solutions was carried out and mineralogical phases were determined by using X-ray diffraction.
• The resistance to sulfate attack of mortars made with quaternary binders was better than that of mortars based on OPC.

Currently, the use of blended cements incorporating various supplementary cementing materials, preserved in aggressive environments has become common. This paper describes the investigation results conducted on the evaluation of the resistance to magnesium sulfate solution (MgSO4) of limestone mortars containing simultaneously; limestone filler, blast furnace slag and natural pozzolan. In this study, the deterioration of limestone mortars due to sulfate attack was evaluated by measuring changes in weight, length and compressive strength at the ages of 30, 60, 90, 120 and 180 days of immersion in exposure environments. The X-ray diffraction was also used in order to determine the different mineral phases. It is noteworthy that, the pH variation of the conservation solutions has been monitored during tests. The exposure solution was renewed monthly until the end of tests. The results showed that, the resistance to sulfate attack of mortars made with quaternary binders was better than that of mortars based on ordinary Portland cement.