Behavior of limestone filler cement mortars exposed to magnesium sulfate attack

In the cement production industry, looking for a less expensive binder using industrial waste and natural resources has become a major concern for the deficit level in the manufacture of Portland cement. However, despite the technical, economic and environmental benefits brought by the use of blended cements, they are associated with disadvantages. The objective of this paper is to study the effects of the incorporation of limestone fillers on the mechanical properties and durability of mortars prepared in different combinations based on this admixture material. The durability was evaluated after immersing the specimens in a 5% solution of magnesium sulfate for periods up to 360 days, and the penetration of chloride ions. The test results demonstrated that mortar and paste samples incorporating higher replacement levels of limestone filler were more susceptible to sulfate attack. According to microstructural analysis, such as DRX, the deterioration was significantly associated with formation of thaumasite, gypsum, and the brucite in the deteriorated parts of the specimens.