Performance of Sanitation Mortars Against Chloride Ion Migration in Contaminated Historical Masonry

This study evaluates the performance of a rehabilitation mortar in controlling chloride ion migration in artificially contaminated ceramic masonry under controlled laboratory conditions. Coatings with thicknesses of 3 cm, 5 cm, and 7 cm were applied to ceramic brick substrates saturated with saline solution and exposed to accelerated contamination. Chloride concentration profiles were determined by potentiometric titration after 120 days of curing. The results showed that the rehabilitation mortar effectively retained soluble salts within its porous matrix, limiting their migration toward the surface. The 3 cm coating provided satisfactory salt retention and reduced the potential for surface efflorescence. Among the evaluated thicknesses, the 5 cm coating exhibited the most favorable chloride distribution, characterized by a pronounced concentration peak at the substrate–mortar interface followed by a sharp decrease toward the external surface, indicating the formation of an effective chloride retention zone. In contrast, the 7 cm coating showed a more homogeneous ion distribution but a less defined retention profile. The results demonstrate the potential of the rehabilitation mortar to act as a protective barrier under controlled laboratory conditions using artificially contaminated ceramic substrates. These findings provide experimental evidence that may support future applications in salt-contaminated historic masonry, although further validation under real field conditions is still required.