Salt resistant mortars: Present knowledge and future perspectives

Salt crystallization damage is one of the most common causes of decay for bedding, pointing and plastering mortar. Attempts to tackle the problem have been mainly focused on increasing the mechanical strength of the mortar, by the replacement of lime with (PTL) cement, or on reducing the moisture transport capacity, by the addition of silicone based water repellents. Both solutions showed to often have a limited durability to salt decay and a low compatibility with historical buildings. Recently research has started to explore new possibilities for improving the durability of mortars to salt damage; these include engineering of the pore size, replacing of silicone based additives with natural organic water repellent substances and mixing-in of salt crystallization inhibitors able to reduce the harmfulness of salt crystallization. Some preliminary studies show that these directions can be promising for obtaining more durable mortars, compatible with historical buildings.Architectural Engineering and TechnologyArchitectur